CINXE.COM

<!DOCTYPE html> <html lang="en-US"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1"> <link rel="profile" href="http://gmpg.org/xfn/11"> <link rel="pingback" href="https://phenomenex.blog/xmlrpc.php"> <meta name='robots' content='index, follow, max-image-preview:large, max-snippet:-1, max-video-preview:-1' /> <style>img:is([sizes="auto" i], [sizes^="auto," i]) { contain-intrinsic-size: 3000px 1500px }</style>  <script data-cfasync="false" data-pagespeed-no-defer> var gtm4wp_datalayer_name = "dataLayer"; var dataLayer = dataLayer || []; const gtm4wp_scrollerscript_debugmode = false; const gtm4wp_scrollerscript_callbacktime = 100; const gtm4wp_scrollerscript_readerlocation = 150; const gtm4wp_scrollerscript_contentelementid = "content"; const gtm4wp_scrollerscript_scannertime = 60; </script>  <script id='google_gtagjs-js-consent-mode-data-layer'> window.dataLayer = window.dataLayer || [];function gtag(){dataLayer.push(arguments);} gtag('consent', 'default', {"ad_personalization":"denied","ad_storage":"denied","ad_user_data":"denied","analytics_storage":"denied","functionality_storage":"denied","security_storage":"denied","personalization_storage":"denied","region":["AT","BE","BG","CH","CY","CZ","DE","DK","EE","ES","FI","FR","GB","GR","HR","HU","IE","IS","IT","LI","LT","LU","LV","MT","NL","NO","PL","PT","RO","SE","SI","SK"],"wait_for_update":500}); window._googlesitekitConsentCategoryMap = {"statistics":["analytics_storage"],"marketing":["ad_storage","ad_user_data","ad_personalization"],"functional":["functionality_storage","security_storage"],"preferences":["personalization_storage"]}; window._googlesitekitConsents = {"ad_personalization":"denied","ad_storage":"denied","ad_user_data":"denied","analytics_storage":"denied","functionality_storage":"denied","security_storage":"denied","personalization_storage":"denied","region":["AT","BE","BG","CH","CY","CZ","DE","DK","EE","ES","FI","FR","GB","GR","HR","HU","IE","IS","IT","LI","LT","LU","LV","MT","NL","NO","PL","PT","RO","SE","SI","SK"],"wait_for_update":500}</script>   <title>HPLC Guard Columns: How They Work - SCIENCE UNFILTERED</title> <link rel="canonical" href="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/" /> <meta property="og:locale" content="en_US" /> <meta property="og:type" content="article" /> <meta property="og:title" content="HPLC Guard Columns: How They Work - SCIENCE UNFILTERED" /> <meta property="og:description" content="Download PDF Author – Rajesh Babu Dandamudi, Ph.D., Phenomenex Technical Manager This morning, I was watching a video clip forwarded by one of..." /> <meta property="og:url" content="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/" /> <meta property="og:site_name" content="SCIENCE UNFILTERED" /> <meta property="article:publisher" content="https://www.facebook.com/Phenomenex/" /> <meta property="article:published_time" content="2021-06-17T15:00:00+00:00" /> <meta property="article:modified_time" content="2021-06-17T20:20:14+00:00" /> <meta property="og:image" content="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=1200%2C675&ssl=1" /> <meta property="og:image:width" content="1200" /> <meta property="og:image:height" content="675" /> <meta property="og:image:type" content="image/png" /> <meta name="author" content="Science Unfiltered" /> <meta name="twitter:card" content="summary_large_image" /> <meta name="twitter:creator" content="@Phenomenex" /> <meta name="twitter:site" content="@Phenomenex" /> <meta name="twitter:label1" content="Written by" /> <meta name="twitter:data1" content="Science Unfiltered" /> <meta name="twitter:label2" content="Est. reading time" /> <meta name="twitter:data2" content="6 minutes" /> <script type="application/ld+json" class="yoast-schema-graph">{"@context":"https://schema.org","@graph":[{"@type":"Article","@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/#article","isPartOf":{"@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/"},"author":{"name":"Science Unfiltered","@id":"https://phenomenex.blog/#/schema/person/7d33f13b460fe0c480a13a54723a36ba"},"headline":"HPLC Guard Columns: How They Work","datePublished":"2021-06-17T15:00:00+00:00","dateModified":"2021-06-17T20:20:14+00:00","mainEntityOfPage":{"@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/"},"wordCount":1097,"commentCount":0,"publisher":{"@id":"https://phenomenex.blog/#organization"},"image":{"@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/#primaryimage"},"thumbnailUrl":"https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=1200%2C675&ssl=1","keywords":["Guard Cartridge","Guard Column","security guard"],"articleSection":["Featured","Liquid Chromatography (LC)","Technical Tips"],"inLanguage":"en-US","potentialAction":[{"@type":"CommentAction","name":"Comment","target":["https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/#respond"]}]},{"@type":"WebPage","@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/","url":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/","name":"HPLC Guard Columns: How They Work - SCIENCE UNFILTERED","isPartOf":{"@id":"https://phenomenex.blog/#website"},"primaryImageOfPage":{"@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/#primaryimage"},"image":{"@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/#primaryimage"},"thumbnailUrl":"https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=1200%2C675&ssl=1","datePublished":"2021-06-17T15:00:00+00:00","dateModified":"2021-06-17T20:20:14+00:00","breadcrumb":{"@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/"]}]},{"@type":"ImageObject","inLanguage":"en-US","@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/#primaryimage","url":"https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=1200%2C675&ssl=1","contentUrl":"https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=1200%2C675&ssl=1","width":1200,"height":675},{"@type":"BreadcrumbList","@id":"https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://phenomenex.blog/"},{"@type":"ListItem","position":2,"name":"HPLC Guard Columns: How They Work"}]},{"@type":"WebSite","@id":"https://phenomenex.blog/#website","url":"https://phenomenex.blog/","name":"SCIENCE UNFILTERED","description":"","publisher":{"@id":"https://phenomenex.blog/#organization"},"potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://phenomenex.blog/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Organization","@id":"https://phenomenex.blog/#organization","name":"Phenomenex","url":"https://phenomenex.blog/","logo":{"@type":"ImageObject","inLanguage":"en-US","@id":"https://phenomenex.blog/#/schema/logo/image/","url":"https://i0.wp.com/phenomenex.blog/wp-content/uploads/2022/02/1538630_675153929213140_4471464164002657757_n.png?fit=640%2C640&ssl=1","contentUrl":"https://i0.wp.com/phenomenex.blog/wp-content/uploads/2022/02/1538630_675153929213140_4471464164002657757_n.png?fit=640%2C640&ssl=1","width":640,"height":640,"caption":"Phenomenex"},"image":{"@id":"https://phenomenex.blog/#/schema/logo/image/"},"sameAs":["https://www.facebook.com/Phenomenex/","https://x.com/Phenomenex","https://www.instagram.com/phenomenexinc","https://www.linkedin.com/company/phenomenex","https://www.pinterest.com/phenomenex/","https://www.youtube.com/channel/UCgXbyGXbLyJw_cEnsqoDfFw"]},{"@type":"Person","@id":"https://phenomenex.blog/#/schema/person/7d33f13b460fe0c480a13a54723a36ba","name":"Science Unfiltered","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https://phenomenex.blog/#/schema/person/image/","url":"https://secure.gravatar.com/avatar/859052c5ad8ec9239d6338c10603a5c4?s=96&d=identicon&r=g","contentUrl":"https://secure.gravatar.com/avatar/859052c5ad8ec9239d6338c10603a5c4?s=96&d=identicon&r=g","caption":"Science Unfiltered"},"url":"https://phenomenex.blog/author/phenomenex/"}]}</script>  <link rel='dns-prefetch' href='//secure.gravatar.com' /> <link rel='dns-prefetch' href='//www.googletagmanager.com' /> <link rel='dns-prefetch' href='//stats.wp.com' /> <link rel='dns-prefetch' href='//fonts-api.wp.com' /> <link rel='dns-prefetch' href='//widgets.wp.com' /> <link rel='dns-prefetch' href='//s0.wp.com' /> <link rel='dns-prefetch' href='//0.gravatar.com' /> <link rel='dns-prefetch' href='//1.gravatar.com' /> <link rel='dns-prefetch' href='//2.gravatar.com' /> <link rel='dns-prefetch' href='//jetpack.wordpress.com' /> <link rel='dns-prefetch' href='//public-api.wordpress.com' /> <link rel='preconnect' href='//i0.wp.com' /> <link rel='preconnect' href='//c0.wp.com' /> <link rel="alternate" type="application/rss+xml" title="SCIENCE UNFILTERED » Feed" href="https://phenomenex.blog/feed/" /> <link rel="alternate" type="application/rss+xml" title="SCIENCE UNFILTERED » Comments Feed" href="https://phenomenex.blog/comments/feed/" /> <link rel="alternate" type="application/rss+xml" title="SCIENCE UNFILTERED » HPLC Guard Columns: How They Work Comments Feed" href="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/feed/" /> <script type="text/javascript"> /* <![CDATA[ */ window._wpemojiSettings = {"baseUrl":"https:\/\/s.w.org\/images\/core\/emoji\/15.0.3\/72x72\/","ext":".png","svgUrl":"https:\/\/s.w.org\/images\/core\/emoji\/15.0.3\/svg\/","svgExt":".svg","source":{"concatemoji":"https:\/\/phenomenex.blog\/wp-includes\/js\/wp-emoji-release.min.js?ver=6.7.1"}}; /*! This file is auto-generated */ !function(i,n){var o,s,e;function c(e){try{var t={supportTests:e,timestamp:(new Date).valueOf()};sessionStorage.setItem(o,JSON.stringify(t))}catch(e){}}function p(e,t,n){e.clearRect(0,0,e.canvas.width,e.canvas.height),e.fillText(t,0,0);var t=new Uint32Array(e.getImageData(0,0,e.canvas.width,e.canvas.height).data),r=(e.clearRect(0,0,e.canvas.width,e.canvas.height),e.fillText(n,0,0),new Uint32Array(e.getImageData(0,0,e.canvas.width,e.canvas.height).data));return t.every(function(e,t){return e===r[t]})}function u(e,t,n){switch(t){case"flag":return n(e,"\ud83c\udff3\ufe0f\u200d\u26a7\ufe0f","\ud83c\udff3\ufe0f\u200b\u26a7\ufe0f")?!1:!n(e,"\ud83c\uddfa\ud83c\uddf3","\ud83c\uddfa\u200b\ud83c\uddf3")&&!n(e,"\ud83c\udff4\udb40\udc67\udb40\udc62\udb40\udc65\udb40\udc6e\udb40\udc67\udb40\udc7f","\ud83c\udff4\u200b\udb40\udc67\u200b\udb40\udc62\u200b\udb40\udc65\u200b\udb40\udc6e\u200b\udb40\udc67\u200b\udb40\udc7f");case"emoji":return!n(e,"\ud83d\udc26\u200d\u2b1b","\ud83d\udc26\u200b\u2b1b")}return!1}function f(e,t,n){var r="undefined"!=typeof WorkerGlobalScope&&self instanceof WorkerGlobalScope?new OffscreenCanvas(300,150):i.createElement("canvas"),a=r.getContext("2d",{willReadFrequently:!0}),o=(a.textBaseline="top",a.font="600 32px Arial",{});return e.forEach(function(e){o[e]=t(a,e,n)}),o}function t(e){var t=i.createElement("script");t.src=e,t.defer=!0,i.head.appendChild(t)}"undefined"!=typeof Promise&&(o="wpEmojiSettingsSupports",s=["flag","emoji"],n.supports={everything:!0,everythingExceptFlag:!0},e=new Promise(function(e){i.addEventListener("DOMContentLoaded",e,{once:!0})}),new Promise(function(t){var n=function(){try{var e=JSON.parse(sessionStorage.getItem(o));if("object"==typeof e&&"number"==typeof e.timestamp&&(new Date).valueOf()<e.timestamp+604800&&"object"==typeof e.supportTests)return e.supportTests}catch(e){}return null}();if(!n){if("undefined"!=typeof Worker&&"undefined"!=typeof OffscreenCanvas&&"undefined"!=typeof URL&&URL.createObjectURL&&"undefined"!=typeof Blob)try{var e="postMessage("+f.toString()+"("+[JSON.stringify(s),u.toString(),p.toString()].join(",")+"));",r=new Blob([e],{type:"text/javascript"}),a=new Worker(URL.createObjectURL(r),{name:"wpTestEmojiSupports"});return void(a.onmessage=function(e){c(n=e.data),a.terminate(),t(n)})}catch(e){}c(n=f(s,u,p))}t(n)}).then(function(e){for(var t in e)n.supports[t]=e[t],n.supports.everything=n.supports.everything&&n.supports[t],"flag"!==t&&(n.supports.everythingExceptFlag=n.supports.everythingExceptFlag&&n.supports[t]);n.supports.everythingExceptFlag=n.supports.everythingExceptFlag&&!n.supports.flag,n.DOMReady=!1,n.readyCallback=function(){n.DOMReady=!0}}).then(function(){return e}).then(function(){var e;n.supports.everything||(n.readyCallback(),(e=n.source||{}).concatemoji?t(e.concatemoji):e.wpemoji&&e.twemoji&&(t(e.twemoji),t(e.wpemoji)))}))}((window,document),window._wpemojiSettings); /* ]]> */ </script> <link rel='stylesheet' id='all-css-59e45f55fe0e9fdeb08fe9db418f3e38' href='https://phenomenex.blog/_static/??-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' type='text/css' media='all' /> <style id='wp-block-library-inline-css'> .has-text-align-justify{text-align:justify;} </style> <link rel='stylesheet' id='dashicons-css' href='https://phenomenex.blog/wp-includes/css/dashicons.min.css?ver=6.7.1' media='all' /> <style id='wp-emoji-styles-inline-css'> img.wp-smiley, img.emoji { display: inline !important; border: none !important; box-shadow: none !important; height: 1em !important; width: 1em !important; margin: 0 0.07em !important; vertical-align: -0.1em !important; background: none !important; padding: 0 !important; } </style> <style id='outermost-social-sharing-style-inline-css'> .wp-block-outermost-social-sharing{align-items:flex-start;background:none;box-sizing:border-box;margin-left:0;padding-left:0;padding-right:0;text-indent:0}.wp-block-outermost-social-sharing .outermost-social-sharing-link a,.wp-block-outermost-social-sharing .outermost-social-sharing-link a:hover{border-bottom:0;box-shadow:none;text-decoration:none}.wp-block-outermost-social-sharing .outermost-social-sharing-link a{padding:.25em}.wp-block-outermost-social-sharing .outermost-social-sharing-link svg{height:1em;width:1em}.wp-block-outermost-social-sharing .outermost-social-sharing-link span:not(.screen-reader-text){font-size:.65em;margin-left:.5em;margin-right:.5em}.wp-block-outermost-social-sharing.has-small-icon-size{font-size:16px}.wp-block-outermost-social-sharing,.wp-block-outermost-social-sharing.has-normal-icon-size{font-size:24px}.wp-block-outermost-social-sharing.has-large-icon-size{font-size:36px}.wp-block-outermost-social-sharing.has-huge-icon-size{font-size:48px}.wp-block-outermost-social-sharing.aligncenter{display:flex;justify-content:center}.wp-block-outermost-social-sharing.alignright{justify-content:flex-end}.wp-block-outermost-social-sharing-link{border-radius:9999px;display:block;height:auto;transition:transform .1s ease}.wp-block-outermost-social-sharing-link a{align-items:center;display:flex;line-height:0;transition:transform .1s ease}.wp-block-outermost-social-sharing-link:hover{transform:scale(1.1)}.wp-block-outermost-social-sharing .wp-block-outermost-social-sharing-link .wp-block-outermost-social-sharing-link-anchor,.wp-block-outermost-social-sharing .wp-block-outermost-social-sharing-link .wp-block-outermost-social-sharing-link-anchor svg,.wp-block-outermost-social-sharing .wp-block-outermost-social-sharing-link .wp-block-outermost-social-sharing-link-anchor:active,.wp-block-outermost-social-sharing .wp-block-outermost-social-sharing-link .wp-block-outermost-social-sharing-link-anchor:hover,.wp-block-outermost-social-sharing .wp-block-outermost-social-sharing-link .wp-block-outermost-social-sharing-link-anchor:visited{color:currentColor;fill:currentColor}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link{background-color:#f0f0f0;color:#444}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-bluesky{background-color:#1083fe;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-facebook{background-color:#1877f2;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-flipboard{background-color:#e12828;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-line{background-color:#06c755;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-linkedin{background-color:#0a66c2;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-pinterest{background-color:#bd081c;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-pocket{background-color:#ef4056;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-reddit{background-color:#ff4500;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-skype{background-color:#0078ca;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-telegram{background-color:#229ed9;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-threads{background-color:#000;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-tumblr{background-color:#011935;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-viber{background-color:#665ca7;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-whatsapp{background-color:#25d366;color:#fff}.wp-block-outermost-social-sharing:not(.is-style-logos-only) .outermost-social-sharing-link-x{background-color:#000;color:#fff}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link{background:none}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link a{padding:0}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link svg{height:1.25em;width:1.25em}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link{color:#444}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-bluesky{color:#1083fe}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-facebook{color:#1877f2}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-flipboard{color:#e12828}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-line{color:#06c755}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-linkedin{color:#0a66c2}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-pinterest{color:#bd081c}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-pocket{color:#ef4056}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-reddit{color:#ff4500}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-skype{color:#0078ca}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-telegram{color:#229ed9}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-threads{color:#000}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-tumblr{color:#011935}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-twitter{color:#1da1f2}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-viber{color:#665ca7}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-whatsapp{color:#25d366}.wp-block-outermost-social-sharing.is-style-logos-only .outermost-social-sharing-link-x{color:#000}.wp-block-outermost-social-sharing.is-style-pill-shape .outermost-social-sharing-link{width:auto}.wp-block-outermost-social-sharing.is-style-pill-shape .outermost-social-sharing-link a{padding-left:.6666666667em;padding-right:.6666666667em}.wp-block-post-template.is-flex-container .wp-block-outermost-social-sharing li{width:auto} </style> <style id='jetpack-sharing-buttons-style-inline-css'> .jetpack-sharing-buttons__services-list{display:flex;flex-direction:row;flex-wrap:wrap;gap:0;list-style-type:none;margin:5px;padding:0}.jetpack-sharing-buttons__services-list.has-small-icon-size{font-size:12px}.jetpack-sharing-buttons__services-list.has-normal-icon-size{font-size:16px}.jetpack-sharing-buttons__services-list.has-large-icon-size{font-size:24px}.jetpack-sharing-buttons__services-list.has-huge-icon-size{font-size:36px}@media print{.jetpack-sharing-buttons__services-list{display:none!important}}.editor-styles-wrapper .wp-block-jetpack-sharing-buttons{gap:0;padding-inline-start:0}ul.jetpack-sharing-buttons__services-list.has-background{padding:1.25em 2.375em} </style> <style id='classic-theme-styles-inline-css'> /*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} </style> <style id='global-styles-inline-css'> :root{--wp--preset--aspect-ratio--square: 1;--wp--preset--aspect-ratio--4-3: 4/3;--wp--preset--aspect-ratio--3-4: 3/4;--wp--preset--aspect-ratio--3-2: 3/2;--wp--preset--aspect-ratio--2-3: 2/3;--wp--preset--aspect-ratio--16-9: 16/9;--wp--preset--aspect-ratio--9-16: 9/16;--wp--preset--color--black: #000000;--wp--preset--color--cyan-bluish-gray: #abb8c3;--wp--preset--color--white: #ffffff;--wp--preset--color--pale-pink: #f78da7;--wp--preset--color--vivid-red: #cf2e2e;--wp--preset--color--luminous-vivid-orange: #ff6900;--wp--preset--color--luminous-vivid-amber: #fcb900;--wp--preset--color--light-green-cyan: #7bdcb5;--wp--preset--color--vivid-green-cyan: #00d084;--wp--preset--color--pale-cyan-blue: #8ed1fc;--wp--preset--color--vivid-cyan-blue: #0693e3;--wp--preset--color--vivid-purple: #9b51e0;--wp--preset--gradient--vivid-cyan-blue-to-vivid-purple: linear-gradient(135deg,rgba(6,147,227,1) 0%,rgb(155,81,224) 100%);--wp--preset--gradient--light-green-cyan-to-vivid-green-cyan: linear-gradient(135deg,rgb(122,220,180) 0%,rgb(0,208,130) 100%);--wp--preset--gradient--luminous-vivid-amber-to-luminous-vivid-orange: linear-gradient(135deg,rgba(252,185,0,1) 0%,rgba(255,105,0,1) 100%);--wp--preset--gradient--luminous-vivid-orange-to-vivid-red: linear-gradient(135deg,rgba(255,105,0,1) 0%,rgb(207,46,46) 100%);--wp--preset--gradient--very-light-gray-to-cyan-bluish-gray: linear-gradient(135deg,rgb(238,238,238) 0%,rgb(169,184,195) 100%);--wp--preset--gradient--cool-to-warm-spectrum: linear-gradient(135deg,rgb(74,234,220) 0%,rgb(151,120,209) 20%,rgb(207,42,186) 40%,rgb(238,44,130) 60%,rgb(251,105,98) 80%,rgb(254,248,76) 100%);--wp--preset--gradient--blush-light-purple: linear-gradient(135deg,rgb(255,206,236) 0%,rgb(152,150,240) 100%);--wp--preset--gradient--blush-bordeaux: linear-gradient(135deg,rgb(254,205,165) 0%,rgb(254,45,45) 50%,rgb(107,0,62) 100%);--wp--preset--gradient--luminous-dusk: linear-gradient(135deg,rgb(255,203,112) 0%,rgb(199,81,192) 50%,rgb(65,88,208) 100%);--wp--preset--gradient--pale-ocean: linear-gradient(135deg,rgb(255,245,203) 0%,rgb(182,227,212) 50%,rgb(51,167,181) 100%);--wp--preset--gradient--electric-grass: linear-gradient(135deg,rgb(202,248,128) 0%,rgb(113,206,126) 100%);--wp--preset--gradient--midnight: linear-gradient(135deg,rgb(2,3,129) 0%,rgb(40,116,252) 100%);--wp--preset--font-size--small: 13px;--wp--preset--font-size--medium: 20px;--wp--preset--font-size--large: 36px;--wp--preset--font-size--x-large: 42px;--wp--preset--font-family--albert-sans: 'Albert Sans', sans-serif;--wp--preset--font-family--alegreya: Alegreya, serif;--wp--preset--font-family--arvo: Arvo, serif;--wp--preset--font-family--bodoni-moda: 'Bodoni Moda', serif;--wp--preset--font-family--bricolage-grotesque: 'Bricolage Grotesque', sans-serif;--wp--preset--font-family--cabin: Cabin, sans-serif;--wp--preset--font-family--chivo: Chivo, sans-serif;--wp--preset--font-family--commissioner: Commissioner, sans-serif;--wp--preset--font-family--cormorant: Cormorant, serif;--wp--preset--font-family--courier-prime: 'Courier Prime', monospace;--wp--preset--font-family--crimson-pro: 'Crimson Pro', serif;--wp--preset--font-family--dm-mono: 'DM Mono', monospace;--wp--preset--font-family--dm-sans: 'DM Sans', sans-serif;--wp--preset--font-family--dm-serif-display: 'DM Serif Display', serif;--wp--preset--font-family--domine: Domine, serif;--wp--preset--font-family--eb-garamond: 'EB Garamond', serif;--wp--preset--font-family--epilogue: Epilogue, sans-serif;--wp--preset--font-family--fahkwang: Fahkwang, sans-serif;--wp--preset--font-family--figtree: Figtree, sans-serif;--wp--preset--font-family--fira-sans: 'Fira Sans', sans-serif;--wp--preset--font-family--fjalla-one: 'Fjalla One', sans-serif;--wp--preset--font-family--fraunces: Fraunces, serif;--wp--preset--font-family--gabarito: Gabarito, system-ui;--wp--preset--font-family--ibm-plex-mono: 'IBM Plex Mono', monospace;--wp--preset--font-family--ibm-plex-sans: 'IBM Plex Sans', sans-serif;--wp--preset--font-family--ibarra-real-nova: 'Ibarra Real Nova', serif;--wp--preset--font-family--instrument-serif: 'Instrument Serif', serif;--wp--preset--font-family--inter: Inter, sans-serif;--wp--preset--font-family--josefin-sans: 'Josefin Sans', sans-serif;--wp--preset--font-family--jost: Jost, sans-serif;--wp--preset--font-family--libre-baskerville: 'Libre Baskerville', serif;--wp--preset--font-family--libre-franklin: 'Libre Franklin', sans-serif;--wp--preset--font-family--literata: Literata, serif;--wp--preset--font-family--lora: Lora, serif;--wp--preset--font-family--merriweather: Merriweather, serif;--wp--preset--font-family--montserrat: Montserrat, sans-serif;--wp--preset--font-family--newsreader: Newsreader, serif;--wp--preset--font-family--noto-sans-mono: 'Noto Sans Mono', sans-serif;--wp--preset--font-family--nunito: Nunito, sans-serif;--wp--preset--font-family--open-sans: 'Open Sans', sans-serif;--wp--preset--font-family--overpass: Overpass, sans-serif;--wp--preset--font-family--pt-serif: 'PT Serif', serif;--wp--preset--font-family--petrona: Petrona, serif;--wp--preset--font-family--piazzolla: Piazzolla, serif;--wp--preset--font-family--playfair-display: 'Playfair Display', serif;--wp--preset--font-family--plus-jakarta-sans: 'Plus Jakarta Sans', sans-serif;--wp--preset--font-family--poppins: Poppins, sans-serif;--wp--preset--font-family--raleway: Raleway, sans-serif;--wp--preset--font-family--roboto: Roboto, sans-serif;--wp--preset--font-family--roboto-slab: 'Roboto Slab', serif;--wp--preset--font-family--rubik: Rubik, sans-serif;--wp--preset--font-family--rufina: Rufina, serif;--wp--preset--font-family--sora: Sora, sans-serif;--wp--preset--font-family--source-sans-3: 'Source Sans 3', sans-serif;--wp--preset--font-family--source-serif-4: 'Source Serif 4', serif;--wp--preset--font-family--space-mono: 'Space Mono', monospace;--wp--preset--font-family--syne: Syne, sans-serif;--wp--preset--font-family--texturina: Texturina, serif;--wp--preset--font-family--urbanist: Urbanist, sans-serif;--wp--preset--font-family--work-sans: 'Work Sans', sans-serif;--wp--preset--spacing--20: 0.44rem;--wp--preset--spacing--30: 0.67rem;--wp--preset--spacing--40: 1rem;--wp--preset--spacing--50: 1.5rem;--wp--preset--spacing--60: 2.25rem;--wp--preset--spacing--70: 3.38rem;--wp--preset--spacing--80: 5.06rem;--wp--preset--shadow--natural: 6px 6px 9px rgba(0, 0, 0, 0.2);--wp--preset--shadow--deep: 12px 12px 50px rgba(0, 0, 0, 0.4);--wp--preset--shadow--sharp: 6px 6px 0px rgba(0, 0, 0, 0.2);--wp--preset--shadow--outlined: 6px 6px 0px -3px rgba(255, 255, 255, 1), 6px 6px rgba(0, 0, 0, 1);--wp--preset--shadow--crisp: 6px 6px 0px rgba(0, 0, 0, 1);}:where(.is-layout-flex){gap: 0.5em;}:where(.is-layout-grid){gap: 0.5em;}body .is-layout-flex{display: flex;}.is-layout-flex{flex-wrap: wrap;align-items: center;}.is-layout-flex > :is(*, div){margin: 0;}body .is-layout-grid{display: grid;}.is-layout-grid > :is(*, div){margin: 0;}:where(.wp-block-columns.is-layout-flex){gap: 2em;}:where(.wp-block-columns.is-layout-grid){gap: 2em;}:where(.wp-block-post-template.is-layout-flex){gap: 1.25em;}:where(.wp-block-post-template.is-layout-grid){gap: 1.25em;}.has-black-color{color: var(--wp--preset--color--black) !important;}.has-cyan-bluish-gray-color{color: var(--wp--preset--color--cyan-bluish-gray) !important;}.has-white-color{color: var(--wp--preset--color--white) !important;}.has-pale-pink-color{color: var(--wp--preset--color--pale-pink) !important;}.has-vivid-red-color{color: var(--wp--preset--color--vivid-red) !important;}.has-luminous-vivid-orange-color{color: var(--wp--preset--color--luminous-vivid-orange) !important;}.has-luminous-vivid-amber-color{color: var(--wp--preset--color--luminous-vivid-amber) !important;}.has-light-green-cyan-color{color: var(--wp--preset--color--light-green-cyan) !important;}.has-vivid-green-cyan-color{color: var(--wp--preset--color--vivid-green-cyan) !important;}.has-pale-cyan-blue-color{color: var(--wp--preset--color--pale-cyan-blue) !important;}.has-vivid-cyan-blue-color{color: var(--wp--preset--color--vivid-cyan-blue) !important;}.has-vivid-purple-color{color: var(--wp--preset--color--vivid-purple) !important;}.has-black-background-color{background-color: var(--wp--preset--color--black) !important;}.has-cyan-bluish-gray-background-color{background-color: var(--wp--preset--color--cyan-bluish-gray) !important;}.has-white-background-color{background-color: var(--wp--preset--color--white) !important;}.has-pale-pink-background-color{background-color: var(--wp--preset--color--pale-pink) !important;}.has-vivid-red-background-color{background-color: var(--wp--preset--color--vivid-red) !important;}.has-luminous-vivid-orange-background-color{background-color: var(--wp--preset--color--luminous-vivid-orange) !important;}.has-luminous-vivid-amber-background-color{background-color: var(--wp--preset--color--luminous-vivid-amber) !important;}.has-light-green-cyan-background-color{background-color: var(--wp--preset--color--light-green-cyan) !important;}.has-vivid-green-cyan-background-color{background-color: var(--wp--preset--color--vivid-green-cyan) !important;}.has-pale-cyan-blue-background-color{background-color: var(--wp--preset--color--pale-cyan-blue) !important;}.has-vivid-cyan-blue-background-color{background-color: var(--wp--preset--color--vivid-cyan-blue) !important;}.has-vivid-purple-background-color{background-color: var(--wp--preset--color--vivid-purple) !important;}.has-black-border-color{border-color: var(--wp--preset--color--black) !important;}.has-cyan-bluish-gray-border-color{border-color: var(--wp--preset--color--cyan-bluish-gray) !important;}.has-white-border-color{border-color: var(--wp--preset--color--white) !important;}.has-pale-pink-border-color{border-color: var(--wp--preset--color--pale-pink) !important;}.has-vivid-red-border-color{border-color: var(--wp--preset--color--vivid-red) !important;}.has-luminous-vivid-orange-border-color{border-color: var(--wp--preset--color--luminous-vivid-orange) !important;}.has-luminous-vivid-amber-border-color{border-color: var(--wp--preset--color--luminous-vivid-amber) !important;}.has-light-green-cyan-border-color{border-color: var(--wp--preset--color--light-green-cyan) !important;}.has-vivid-green-cyan-border-color{border-color: var(--wp--preset--color--vivid-green-cyan) !important;}.has-pale-cyan-blue-border-color{border-color: var(--wp--preset--color--pale-cyan-blue) !important;}.has-vivid-cyan-blue-border-color{border-color: var(--wp--preset--color--vivid-cyan-blue) !important;}.has-vivid-purple-border-color{border-color: var(--wp--preset--color--vivid-purple) !important;}.has-vivid-cyan-blue-to-vivid-purple-gradient-background{background: var(--wp--preset--gradient--vivid-cyan-blue-to-vivid-purple) !important;}.has-light-green-cyan-to-vivid-green-cyan-gradient-background{background: var(--wp--preset--gradient--light-green-cyan-to-vivid-green-cyan) !important;}.has-luminous-vivid-amber-to-luminous-vivid-orange-gradient-background{background: var(--wp--preset--gradient--luminous-vivid-amber-to-luminous-vivid-orange) !important;}.has-luminous-vivid-orange-to-vivid-red-gradient-background{background: var(--wp--preset--gradient--luminous-vivid-orange-to-vivid-red) !important;}.has-very-light-gray-to-cyan-bluish-gray-gradient-background{background: var(--wp--preset--gradient--very-light-gray-to-cyan-bluish-gray) !important;}.has-cool-to-warm-spectrum-gradient-background{background: var(--wp--preset--gradient--cool-to-warm-spectrum) !important;}.has-blush-light-purple-gradient-background{background: var(--wp--preset--gradient--blush-light-purple) !important;}.has-blush-bordeaux-gradient-background{background: var(--wp--preset--gradient--blush-bordeaux) !important;}.has-luminous-dusk-gradient-background{background: var(--wp--preset--gradient--luminous-dusk) !important;}.has-pale-ocean-gradient-background{background: var(--wp--preset--gradient--pale-ocean) !important;}.has-electric-grass-gradient-background{background: var(--wp--preset--gradient--electric-grass) !important;}.has-midnight-gradient-background{background: var(--wp--preset--gradient--midnight) !important;}.has-small-font-size{font-size: var(--wp--preset--font-size--small) !important;}.has-medium-font-size{font-size: var(--wp--preset--font-size--medium) !important;}.has-large-font-size{font-size: var(--wp--preset--font-size--large) !important;}.has-x-large-font-size{font-size: var(--wp--preset--font-size--x-large) !important;}.has-albert-sans-font-family{font-family: var(--wp--preset--font-family--albert-sans) !important;}.has-alegreya-font-family{font-family: var(--wp--preset--font-family--alegreya) !important;}.has-arvo-font-family{font-family: var(--wp--preset--font-family--arvo) !important;}.has-bodoni-moda-font-family{font-family: var(--wp--preset--font-family--bodoni-moda) !important;}.has-bricolage-grotesque-font-family{font-family: var(--wp--preset--font-family--bricolage-grotesque) !important;}.has-cabin-font-family{font-family: var(--wp--preset--font-family--cabin) !important;}.has-chivo-font-family{font-family: var(--wp--preset--font-family--chivo) !important;}.has-commissioner-font-family{font-family: var(--wp--preset--font-family--commissioner) !important;}.has-cormorant-font-family{font-family: var(--wp--preset--font-family--cormorant) !important;}.has-courier-prime-font-family{font-family: var(--wp--preset--font-family--courier-prime) !important;}.has-crimson-pro-font-family{font-family: var(--wp--preset--font-family--crimson-pro) !important;}.has-dm-mono-font-family{font-family: var(--wp--preset--font-family--dm-mono) !important;}.has-dm-sans-font-family{font-family: var(--wp--preset--font-family--dm-sans) !important;}.has-dm-serif-display-font-family{font-family: var(--wp--preset--font-family--dm-serif-display) !important;}.has-domine-font-family{font-family: var(--wp--preset--font-family--domine) !important;}.has-eb-garamond-font-family{font-family: var(--wp--preset--font-family--eb-garamond) !important;}.has-epilogue-font-family{font-family: var(--wp--preset--font-family--epilogue) !important;}.has-fahkwang-font-family{font-family: var(--wp--preset--font-family--fahkwang) !important;}.has-figtree-font-family{font-family: var(--wp--preset--font-family--figtree) !important;}.has-fira-sans-font-family{font-family: var(--wp--preset--font-family--fira-sans) !important;}.has-fjalla-one-font-family{font-family: var(--wp--preset--font-family--fjalla-one) !important;}.has-fraunces-font-family{font-family: var(--wp--preset--font-family--fraunces) !important;}.has-gabarito-font-family{font-family: var(--wp--preset--font-family--gabarito) !important;}.has-ibm-plex-mono-font-family{font-family: var(--wp--preset--font-family--ibm-plex-mono) !important;}.has-ibm-plex-sans-font-family{font-family: var(--wp--preset--font-family--ibm-plex-sans) !important;}.has-ibarra-real-nova-font-family{font-family: var(--wp--preset--font-family--ibarra-real-nova) !important;}.has-instrument-serif-font-family{font-family: var(--wp--preset--font-family--instrument-serif) !important;}.has-inter-font-family{font-family: var(--wp--preset--font-family--inter) !important;}.has-josefin-sans-font-family{font-family: var(--wp--preset--font-family--josefin-sans) !important;}.has-jost-font-family{font-family: var(--wp--preset--font-family--jost) !important;}.has-libre-baskerville-font-family{font-family: var(--wp--preset--font-family--libre-baskerville) !important;}.has-libre-franklin-font-family{font-family: var(--wp--preset--font-family--libre-franklin) !important;}.has-literata-font-family{font-family: var(--wp--preset--font-family--literata) !important;}.has-lora-font-family{font-family: var(--wp--preset--font-family--lora) !important;}.has-merriweather-font-family{font-family: var(--wp--preset--font-family--merriweather) !important;}.has-montserrat-font-family{font-family: var(--wp--preset--font-family--montserrat) !important;}.has-newsreader-font-family{font-family: var(--wp--preset--font-family--newsreader) !important;}.has-noto-sans-mono-font-family{font-family: var(--wp--preset--font-family--noto-sans-mono) !important;}.has-nunito-font-family{font-family: var(--wp--preset--font-family--nunito) !important;}.has-open-sans-font-family{font-family: var(--wp--preset--font-family--open-sans) !important;}.has-overpass-font-family{font-family: var(--wp--preset--font-family--overpass) !important;}.has-pt-serif-font-family{font-family: var(--wp--preset--font-family--pt-serif) !important;}.has-petrona-font-family{font-family: var(--wp--preset--font-family--petrona) !important;}.has-piazzolla-font-family{font-family: var(--wp--preset--font-family--piazzolla) !important;}.has-playfair-display-font-family{font-family: var(--wp--preset--font-family--playfair-display) !important;}.has-plus-jakarta-sans-font-family{font-family: var(--wp--preset--font-family--plus-jakarta-sans) !important;}.has-poppins-font-family{font-family: var(--wp--preset--font-family--poppins) !important;}.has-raleway-font-family{font-family: var(--wp--preset--font-family--raleway) !important;}.has-roboto-font-family{font-family: var(--wp--preset--font-family--roboto) !important;}.has-roboto-slab-font-family{font-family: var(--wp--preset--font-family--roboto-slab) !important;}.has-rubik-font-family{font-family: var(--wp--preset--font-family--rubik) !important;}.has-rufina-font-family{font-family: var(--wp--preset--font-family--rufina) !important;}.has-sora-font-family{font-family: var(--wp--preset--font-family--sora) !important;}.has-source-sans-3-font-family{font-family: var(--wp--preset--font-family--source-sans-3) !important;}.has-source-serif-4-font-family{font-family: var(--wp--preset--font-family--source-serif-4) !important;}.has-space-mono-font-family{font-family: var(--wp--preset--font-family--space-mono) !important;}.has-syne-font-family{font-family: var(--wp--preset--font-family--syne) !important;}.has-texturina-font-family{font-family: var(--wp--preset--font-family--texturina) !important;}.has-urbanist-font-family{font-family: var(--wp--preset--font-family--urbanist) !important;}.has-work-sans-font-family{font-family: var(--wp--preset--font-family--work-sans) !important;} :where(.wp-block-columns.is-layout-flex){gap: 2em;}:where(.wp-block-columns.is-layout-grid){gap: 2em;} :root :where(.wp-block-pullquote){font-size: 1.5em;line-height: 1.6;} :where(.wp-block-post-template.is-layout-flex){gap: 1.25em;}:where(.wp-block-post-template.is-layout-grid){gap: 1.25em;} </style> <link rel='stylesheet' id='murray-title-font-css' href='//fonts-api.wp.com/css?family=Oswald%3A100%2C300%2C400%2C700&ver=6.7.1' media='all' /> <link rel='stylesheet' id='murray-body-font-css' href='//fonts-api.wp.com/css?family=Source+Sans+Pro%3A100%2C300%2C400%2C700&ver=6.7.1' media='all' /> <style id='jetpack-global-styles-frontend-style-inline-css'> :root { --font-headings: unset; --font-base: unset; --font-headings-default: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif; --font-base-default: -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Oxygen-Sans,Ubuntu,Cantarell,"Helvetica Neue",sans-serif;} </style> <script type="text/javascript" src="https://phenomenex.blog/wp-includes/js/jquery/jquery.min.js?ver=3.7.1" id="jquery-core-js"></script> <script type='text/javascript' src='https://phenomenex.blog/wp-includes/js/jquery/jquery-migrate.min.js?m=1686289764'></script> <script type="text/javascript" id="jetpack-mu-wpcom-settings-js-before"> /* <![CDATA[ */ var JETPACK_MU_WPCOM_SETTINGS = {"assetsUrl":"https:\/\/phenomenex.blog\/wp-content\/mu-plugins\/wpcomsh\/vendor\/automattic\/jetpack-mu-wpcom\/src\/build\/"}; /* ]]> */ </script> <script type='text/javascript' src='https://phenomenex.blog/wp-content/plugins/wp-hide-post/public/js/wp-hide-post-public.js?m=1506964897'></script> <script type="text/javascript" src="https://phenomenex.blog/wp-content/plugins/duracelltomi-google-tag-manager/dist/js/analytics-talk-content-tracking.js?ver=1.20.2" id="gtm4wp-scroll-tracking-js"></script> <script type="text/javascript" src="https://phenomenex.blog/wp-content/themes/murray/js/custom.js?ver=6.7.1" id="murray-custom-js-js"></script> <script type="text/javascript" id="murray-custom-js-js-after"> /* <![CDATA[ */ jQuery(document).ready(function() { if (jQuery(window).width() > 768) jQuery('#site-navigation').scrollToFixed(); }); /* ]]> */ </script>    <script type="text/javascript" src="https://www.googletagmanager.com/gtag/js?id=GT-MK5QZRD" id="google_gtagjs-js" async></script> <script type="text/javascript" id="google_gtagjs-js-after"> /* <![CDATA[ */ window.dataLayer = window.dataLayer || [];function gtag(){dataLayer.push(arguments);} gtag("set","linker",{"domains":["phenomenex.blog"]}); gtag("js", new Date()); gtag("set", "developer_id.dZTNiMT", true); gtag("config", "GT-MK5QZRD"); gtag("config", "AW-980727910"); /* ]]> */ </script>  <script type="text/javascript" id="cta-load-variation-js-extra"> /* <![CDATA[ */ var cta_variation = {"cta_id":null,"admin_url":"https:\/\/phenomenex.blog\/wp-admin\/admin-ajax.php","home_url":"https:\/\/phenomenex.blog","split_testing":"1","sticky_cta":"1","page_tracking":"off"}; /* ]]> */ </script> <script type="text/javascript" id="inbound-analytics-js-extra"> /* <![CDATA[ */ var inbound_settings = {"post_id":"12259","post_type":"post","variation_id":"0","ip_address":"8.222.208.146","wp_lead_data":{"lead_id":null,"lead_email":null,"lead_uid":null,"lead_nonce":null},"admin_url":"https:\/\/phenomenex.blog\/wp-admin\/admin-ajax.php","track_time":"2024\/11\/27 11:28:24","page_tracking":"off","search_tracking":"off","comment_tracking":"off","custom_mapping":[],"is_admin":"","ajax_nonce":"f0db608ecd"}; /* ]]> */ </script> <script type='text/javascript' src='https://phenomenex.blog/_static/??wp-content/plugins/cta/assets/js/cta-variation.js,wp-content/plugins/cta/shared/assets/js/frontend/analytics/inboundAnalytics.min.js?m=1550037146'></script> <link rel="https://api.w.org/" href="https://phenomenex.blog/wp-json/" /><link rel="alternate" title="JSON" type="application/json" href="https://phenomenex.blog/wp-json/wp/v2/posts/12259" /><link rel="EditURI" type="application/rsd+xml" title="RSD" href="https://phenomenex.blog/xmlrpc.php?rsd" /> <link rel='shortlink' href='https://wp.me/p63Q0d-3bJ' /> <link rel="alternate" title="oEmbed (JSON)" type="application/json+oembed" href="https://phenomenex.blog/wp-json/oembed/1.0/embed?url=https%3A%2F%2Fphenomenex.blog%2F2021%2F06%2F17%2Fhplc-guard-columns-how-they-work%2F" /> <link rel="alternate" title="oEmbed (XML)" type="text/xml+oembed" href="https://phenomenex.blog/wp-json/oembed/1.0/embed?url=https%3A%2F%2Fphenomenex.blog%2F2021%2F06%2F17%2Fhplc-guard-columns-how-they-work%2F&format=xml" /> <script type="text/javascript">var ajaxurl = "https://phenomenex.blog/wp-admin/admin-ajax.php";</script><meta name="generator" content="Site Kit by Google 1.140.0" /> <script> (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){ (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o), m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m) })(window,document,'script','https://www.google-analytics.com/analytics.js','ga'); ga('create', 'UA-19868279-4', 'auto'); ga('send', 'pageview'); </script>   <script type="application/ld+json">{"@context":"https:\/\/schema.org\/","@type":"BlogPosting","mainEntityOfPage":{"@type":"WebPage","@id":"https:\/\/phenomenex.blog\/2021\/06\/17\/hplc-guard-columns-how-they-work\/"},"url":"https:\/\/phenomenex.blog\/2021\/06\/17\/hplc-guard-columns-how-they-work\/","headline":"HPLC Guard Columns: How They Work","datePublished":"2021-06-17T08:00:00-07:00","dateModified":"2021-06-17T13:20:14-07:00","publisher":{"@type":"Organization","@id":"https:\/\/phenomenex.blog\/#organization","name":"Science Unfiltered","logo":{"@type":"ImageObject","url":"https:\/\/phenomenex.blog\/wp-content\/uploads\/2017\/08\/cropped-phenomenex-logo-3.jpg","width":600,"height":60}},"image":{"@type":"ImageObject","url":"https:\/\/i0.wp.com\/phenomenex.blog\/wp-content\/uploads\/2021\/06\/security-guard-header-blog.png?fit=1200%2C675&ssl=1","width":1200,"height":675},"articleSection":"Featured","keywords":"Guard Cartridge, Guard Column, security guard","description":"Author – Rajesh Babu Dandamudi, Ph.D., Phenomenex Technical Manager This morning, I was watching a video clip forwarded by one of my motorcycle enthusiast friends. This was a video clip of a MotoGP race in which one of the riders loses control over the bike and accidentally slipped. The","author":{"@type":"Person","name":"Science Unfiltered","url":"https:\/\/phenomenex.blog\/author\/phenomenex\/","image":{"@type":"ImageObject","url":"https:\/\/secure.gravatar.com\/avatar\/859052c5ad8ec9239d6338c10603a5c4?s=96&d=identicon&r=g","height":96,"width":96}},"audio":[]}</script> <style>img#wpstats{display:none}</style>   <script data-cfasync="false" data-pagespeed-no-defer type="text/javascript"> var dataLayer_content = {"pagePostType":"post","pagePostType2":"single-post","pageCategory":["featured","liquid-chromatography-lc","technical-tips"],"pageAttributes":["guard-cartridge","guard-column","security-guard"],"pagePostAuthor":"Science Unfiltered","browserName":"Internet Explorer","browserVersion":7,"browserEngineName":"Trident","browserEngineVersion":"","osName":"Windows","osVersion":6,"deviceType":"desktop","deviceManufacturer":"","deviceModel":""}; dataLayer.push( dataLayer_content ); </script> <script data-cfasync="false"> (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start': new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0], j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src= '//www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f); })(window,document,'script','dataLayer','GTM-M85ZQR9'); </script> <style id='custom-css-mods'>.title-font, h1, h2, .section-title { font-family: Oswald; }body { font-family: Source Sans Pro; }#masthead h2.site-description { color: #FFF; }</style> <style type="text/css"> .recentcomments a { display: inline !important; padding: 0 !important; margin: 0 !important; } table.recentcommentsavatartop img.avatar, table.recentcommentsavatarend img.avatar { border: 0px; margin: 0; } table.recentcommentsavatartop a, table.recentcommentsavatarend a { border: 0px !important; background-color: transparent !important; } td.recentcommentsavatarend, td.recentcommentsavatartop { padding: 0px 0px 1px 0px; margin: 0px; } td.recentcommentstextend { border: none !important; padding: 0px 0px 2px 10px; } .rtl td.recentcommentstextend { padding: 0px 10px 2px 0px; } td.recentcommentstexttop { border: none; padding: 0px 0px 0px 10px; } .rtl td.recentcommentstexttop { padding: 0px 10px 0px 0px; } </style> <script type="text/javascript" src="//script.crazyegg.com/pages/scripts/0018/4268.js" async="async" ></script><link rel="amphtml" href="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/amp/"><link rel="icon" href="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2023/01/P-icon.png?fit=32%2C32&ssl=1" sizes="32x32" /> <link rel="icon" href="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2023/01/P-icon.png?fit=173%2C172&ssl=1" sizes="192x192" /> <link rel="apple-touch-icon" href="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2023/01/P-icon.png?fit=173%2C172&ssl=1" /> <meta name="msapplication-TileImage" content="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2023/01/P-icon.png?fit=173%2C172&ssl=1" /> <link rel="stylesheet" type="text/css" id="wp-custom-css" href="https://phenomenex.blog/?custom-css=5e98b1014b" /> <script type='text/javascript'> var _gaq = _gaq || []; _gaq.push(['_setAccount', 'UA-19868279-4']); _gaq.push(['_trackPageview']); (function() { var ga = document.createElement('script'); ga.type = 'text/javascript'; ga.async = true; ga.src = ('https:' === document.location.protocol ? 'https://ssl' : 'http://www') + '.google-analytics.com/ga.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(ga, s); })(); </script>  </head> <body class="post-template-default single single-post postid-12259 single-format-standard wp-custom-logo"> <div id="page" class="hfeed site"> <a class="skip-link screen-reader-text" href="#content">Skip to content</a> <div id="jumbosearch"> <span class="fa fa-remove closeicon"></span> <div class="form"> <form role="search" method="get" class="search-form" action="https://phenomenex.blog/"> <label> <span class="screen-reader-text">Search for:</span> <input type="search" class="search-field" placeholder="Search …" value="" name="s" /> </label> <input type="submit" class="search-submit" value="Search" /> </form> </div> </div> <div id="social-icons-fixed" title="Follow us on Social Media"> <a href="https://www.facebook.com/Phenomenex"> <img src="https://phenomenex.blog/wp-content/themes/murray/assets/images/soshion/facebook.png"> </a> <a href="https://twitter.com/Phenomenex"> <img src="https://phenomenex.blog/wp-content/themes/murray/assets/images/soshion/twitter.png"> </a> <a href="https://www.instagram.com/phenomenex/"> <img src="https://phenomenex.blog/wp-content/themes/murray/assets/images/soshion/instagram.png"> </a> <a href="https://www.youtube.com/phenomenex"> <img src="https://phenomenex.blog/wp-content/themes/murray/assets/images/soshion/youtube.png"> </a> </div> <header id="masthead" class="site-header" role="banner"> <div class="container"> <div class="site-branding"> <div id="site-logo"> <a href="https://phenomenex.blog/" class="custom-logo-link" rel="home"><img width="935" height="230" src="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2024/02/cropped-Phenomenex_white.png?fit=935%2C230&ssl=1" class="custom-logo" alt="Phenomenex" decoding="async" fetchpriority="high" srcset="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2024/02/cropped-Phenomenex_white.png?w=935&ssl=1 935w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2024/02/cropped-Phenomenex_white.png?resize=300%2C74&ssl=1 300w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2024/02/cropped-Phenomenex_white.png?resize=768%2C189&ssl=1 768w" sizes="(max-width: 935px) 100vw, 935px" data-attachment-id="14966" data-permalink="https://phenomenex.blog/cropped-phenomenex_white-png/" data-orig-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2024/02/cropped-Phenomenex_white.png?fit=935%2C230&ssl=1" data-orig-size="935,230" data-comments-opened="1" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}" data-image-title="cropped-Phenomenex_white.png" data-image-description="<p>https://phenomenex.blog/wp-content/uploads/2024/02/cropped-Phenomenex_white.png</p> " data-image-caption="" data-medium-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2024/02/cropped-Phenomenex_white.png?fit=300%2C74&ssl=1" data-large-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2024/02/cropped-Phenomenex_white.png?fit=935%2C230&ssl=1" /></a> </div> <div id="text-title-desc"> <h1 class="site-title title-font"><a href="https://phenomenex.blog/" rel="home">SCIENCE UNFILTERED</a></h1> <h2 class="site-description"></h2> </div> </div> <div class="searchform"> <form role="search" method="get" class="search-form" action="https://phenomenex.blog/"> <label> <span class="screen-reader-text">Search for:</span> <input type="search" class="search-field" placeholder="Search..." value="" name="s" title="Search for:" /> </label> </form> </div> </div> </header> <nav id="site-navigation" class="main-navigation single" role="navigation"> <div class="nav-container container"> <div class="menu-middle-menu-container"><ul id="menu-middle-menu" class="menu"><li id="menu-item-13631" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-home menu-item-has-children menu-item-13631"><a href="https://phenomenex.blog/">Industries</a> <ul class="sub-menu"> <li id="menu-item-14089" class="menu-item menu-item-type-taxonomy menu-item-object-post_tag menu-item-14089"><a href="https://phenomenex.blog/tag/pharmaceutical/">Pharmaceutical</a></li> <li id="menu-item-14090" class="menu-item menu-item-type-taxonomy menu-item-object-post_tag menu-item-14090"><a href="https://phenomenex.blog/tag/biopharmaceuticals/">Biopharma</a></li> <li id="menu-item-13619" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-13619"><a href="https://phenomenex.blog/category/forensics-toxicology-industry-articles/">Clinical/Forensics</a></li> <li id="menu-item-13621" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-has-children menu-item-13621"><a href="https://phenomenex.blog/category/environmental-industry-articles/">Environmental</a> <ul class="sub-menu"> <li id="menu-item-13624" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-13624"><a href="https://phenomenex.blog/category/pfas/">PFAS</a></li> </ul> </li> <li id="menu-item-13622" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-13622"><a href="https://phenomenex.blog/category/food-beverage-industry-articles/">Food</a></li> <li id="menu-item-13620" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-13620"><a href="https://phenomenex.blog/category/cannabis-industry-articles/">Cannabis</a></li> </ul> </li> <li id="menu-item-3148" class="menu-item menu-item-type-taxonomy menu-item-object-category current-post-ancestor current-menu-parent current-post-parent menu-item-3148"><a href="https://phenomenex.blog/category/liquid-chromatography-lc/">LC</a></li> <li id="menu-item-3149" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-3149"><a href="https://phenomenex.blog/category/gas-chromatography-gc/">GC</a></li> <li id="menu-item-3150" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-3150"><a href="https://phenomenex.blog/category/sample-preparation/">Sample Prep</a></li> <li id="menu-item-6795" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-6795"><a href="https://phenomenex.blog/category/science-news/">Fun Science</a></li> <li id="menu-item-6827" class="menu-item menu-item-type-taxonomy menu-item-object-category current-post-ancestor current-menu-parent current-post-parent menu-item-6827"><a href="https://phenomenex.blog/category/technical-tips/">Technical Tips</a></li> <li id="menu-item-14044" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-home menu-item-has-children menu-item-14044"><a href="https://phenomenex.blog/">Global</a> <ul class="sub-menu"> <li id="menu-item-13627" class="menu-item menu-item-type-taxonomy menu-item-object-category menu-item-13627"><a href="https://phenomenex.blog/category/spanish-translated-articles/">Español</a></li> </ul> </li> <li id="menu-item-14112" class="menu-item menu-item-type-custom menu-item-object-custom menu-item-14112"><a href="https://www.phenomenex.com/new-products">Shop Our Products</a></li> </ul></div> </div> </nav>  <div class="mega-container"> <div id="content" class="site-content container"> <div id="primary-mono" class="content-area col-md-8"> <main id="main" class="site-main" role="main"> <article id="post-12259" class="post-12259 post type-post status-publish format-standard has-post-thumbnail hentry category-featured category-liquid-chromatography-lc category-technical-tips tag-guard-cartridge tag-guard-column tag-security-guard"> <div id="featured-image"> <img width="1200" height="675" src="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=1200%2C675&ssl=1" class="attachment-full size-full wp-post-image" alt="" decoding="async" srcset="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?w=1200&ssl=1 1200w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?resize=300%2C169&ssl=1 300w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?resize=1024%2C576&ssl=1 1024w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?resize=768%2C432&ssl=1 768w" sizes="(max-width: 1200px) 100vw, 1200px" data-attachment-id="12286" data-permalink="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/security-guard-header-blog/" data-orig-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=1200%2C675&ssl=1" data-orig-size="1200,675" data-comments-opened="1" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}" data-image-title="security-guard-header-blog" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=300%2C169&ssl=1" data-large-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/security-guard-header-blog.png?fit=1024%2C576&ssl=1" /> </div> <header class="entry-header"> <h1 class="entry-title title-font">HPLC Guard Columns: How They Work</h1> <div class="entry-meta"> <span class="posted-on">Posted on <a href="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/" rel="bookmark"><time class="entry-date published" datetime="2021-06-17T08:00:00-07:00">June 17, 2021</time><time class="updated" datetime="2021-06-17T13:20:14-07:00">June 17, 2021</time></a></span><span class="byline"> by <span class="author vcard"><a class="url fn n" href="https://phenomenex.blog/author/phenomenex/">Science Unfiltered</a></span></span> </div> </header> <div class="entry-content"> <div class="dkpdf-button-container" style=" text-align:right "> <a class="dkpdf-button" href="/2021/06/17/hplc-guard-columns-how-they-work/?pdf=12259" target="_blank"><span class="dkpdf-button-icon"><i class="fa fa-file-pdf-o"></i></span> Download PDF</a> </div> <p></p> <p>Author – Rajesh Babu Dandamudi, Ph.D., Phenomenex Technical Manager</p> <p></p> <p></p> <p>This morning, I was watching a video clip forwarded by one of my motorcycle enthusiast friends. This was a video clip of a MotoGP race in which one of the riders loses control over the bike and accidentally slipped. The riders behind him, not anticipating this sudden event, crashed into each other leading to a pile of bikes. Luckily the crash was not fatal, and all the riders survived. When I tried to understand the reason as to how these riders got saved, I noticed that it is because of their protective gear that they were wearing.</p> <p></p> <p></p> <p>The safety of the rider is of utmost importance when it comes to motorcycle racing, so they protect themselves by using the best protective gear, by anticipating the worst. Similarly, a HPLC column is the main component in LC chromatography because it is the column that is responsible for the separation of the analytes in a matrix. Protecting and taking care of the column ensures that we not only get reliable results but also trouble-free operations. We all know that a HPLC column has a finite life, but how do I ensure that I get maximum life?</p> <p></p> <p></p> <p>To answer this question, let us first look at the possible ways in which a column can get blocked?</p> <p></p> <p></p> <p><strong>Sample Matrix:</strong></p> <p></p> <p></p> <p>Samples introduced onto the HPLC column are often diverse and complex. These samples have many components that might not be compatible with the HPLC method conditions. Injecting such samples without proper sample preparation/pretreatment might lead to the clogging of the column.</p> <p></p> <p></p> <p>Residual proteins and highly hydrophobic compounds like lipids may also not be completely eluted out during reversed phase separations, these tend to slowly get adsorbed onto the column and cause issues.</p> <p></p> <p></p> <p><strong>Incompatible sample diluent and mobile phase:</strong></p> <p></p> <p></p> <p>If the sample diluent is not compatible with the mobile phase then when a sample is introduced into the mobile phase, there is a possibility of the sample precipitating. This is often seen if the diluents are too polar or too non-polar compared to the mobile phase.</p> <p></p> <p></p> <p><strong>Mobile phase buffers:</strong></p> <p></p> <p></p> <p>Buffers are commonly used as mobile phase in HPLC. It is important that these buffer salts be filtered prior to use. Sometimes, due to the difference in the temperature of the laboratory, some of the buffer components tend to precipitate. Using too high concentration of buffer also leads to precipitation.</p> <p></p> <p></p> <p><strong>Fragments from worn out pump seals/rotor seals of injector:</strong></p> <p></p> <p></p> <p>Pump seals and injector rotor seals are often made of rubber material. Due to normal wear and tear, these components tend to generate some debris into the solvent line. If periodic maintenance of the pumps and the injector ports are not done, the debris tends to reach the column frit and block the column.</p> <p></p> <p></p> <figure class="wp-block-image size-large"><a href="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-inlet-frit-shot-for-blog.png?ssl=1"><img data-recalc-dims="1" decoding="async" width="809" height="220" data-attachment-id="12266" data-permalink="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/sec-inlet-frit-shot-for-blog/" data-orig-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-inlet-frit-shot-for-blog.png?fit=809%2C220&ssl=1" data-orig-size="809,220" data-comments-opened="1" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}" data-image-title="sec-inlet-frit-shot-for-blog" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-inlet-frit-shot-for-blog.png?fit=300%2C82&ssl=1" data-large-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-inlet-frit-shot-for-blog.png?fit=809%2C220&ssl=1" src="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-inlet-frit-shot-for-blog.png?resize=809%2C220&ssl=1" alt="HPLC column inlet frit on a new column versus blocked" class="wp-image-12266" srcset="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-inlet-frit-shot-for-blog.png?w=809&ssl=1 809w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-inlet-frit-shot-for-blog.png?resize=300%2C82&ssl=1 300w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-inlet-frit-shot-for-blog.png?resize=768%2C209&ssl=1 768w" sizes="(max-width: 809px) 100vw, 809px" /></a></figure> <p></p> <p></p> <p><strong>Now that we know the possible ways in which a column can get blocked. How do we protect it?</strong></p> <p></p> <p></p> <p>To protect HPLC columns (analytical and preparative) from contamination, like particulates from the injection, unfiltered mobile phase components or fragments from worn pump seals/ rotor seals from the injector, it is recommended to use a guard column.</p> <p></p> <p></p> <p><strong>The next obvious question is, what is a guard column?</strong></p> <p></p> <p></p> <p>A guard column is essentially a mini column, ideally packed with the identical packing material as that of the analytical column and is connected before the analytical column. These columns come in various dimensions to match the requirement of the columns.  The frit in the guard columns is like the one in the analytical column.  This would mean that anything that might potentially block the analytical column would be blocked on the guard column. This block can then be removed by simply replacing the guard cartridges, thereby protecting the life of the analytical column.</p> <p></p> <p></p> <figure class="wp-block-image size-large"><a href="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-column-diagram-for-blog-june.png?ssl=1"><img data-recalc-dims="1" decoding="async" width="540" height="272" data-attachment-id="12269" data-permalink="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/sec-column-diagram-for-blog-june/" data-orig-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-column-diagram-for-blog-june.png?fit=540%2C272&ssl=1" data-orig-size="540,272" data-comments-opened="1" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}" data-image-title="sec-column-diagram-for-blog-june" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-column-diagram-for-blog-june.png?fit=300%2C151&ssl=1" data-large-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-column-diagram-for-blog-june.png?fit=540%2C272&ssl=1" src="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-column-diagram-for-blog-june.png?resize=540%2C272&ssl=1" alt="HPLC guard column -holder, cartridge and fingertight fittings" class="wp-image-12269" srcset="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-column-diagram-for-blog-june.png?w=540&ssl=1 540w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-column-diagram-for-blog-june.png?resize=300%2C151&ssl=1 300w" sizes="(max-width: 540px) 100vw, 540px" /></a></figure> <p></p> <p></p> <p><strong>Components of the Security Guard</strong>™</p> <p></p> <p></p> <figure class="wp-block-image size-large"><a href="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-diagram-contaminants-blog.png?ssl=1"><img data-recalc-dims="1" loading="lazy" decoding="async" width="514" height="235" data-attachment-id="12273" data-permalink="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/sec-diagram-contaminants-blog/" data-orig-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-diagram-contaminants-blog.png?fit=514%2C235&ssl=1" data-orig-size="514,235" data-comments-opened="1" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}" data-image-title="sec-diagram-contaminants-blog" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-diagram-contaminants-blog.png?fit=300%2C137&ssl=1" data-large-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-diagram-contaminants-blog.png?fit=514%2C235&ssl=1" src="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-diagram-contaminants-blog.png?resize=514%2C235&ssl=1" alt="Trapped contaminants using an HPLC guard column" class="wp-image-12273" srcset="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-diagram-contaminants-blog.png?w=514&ssl=1 514w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/sec-diagram-contaminants-blog.png?resize=300%2C137&ssl=1 300w" sizes="auto, (max-width: 514px) 100vw, 514px" /></a><figcaption>C<strong>ut away view of the Security Guard showing the Guard cartridge that can be replaced easily when contaminated.</strong></figcaption></figure> <p></p> <p></p> <p>To understand the role of a guard column on the column life we have performed an accelerated lifetime test using an endogenous biological matrix injected onto a core-shell column (Kinetex 2.6 μm C18 50 × 4.6 mm column Phenomenex, Inc. Torrance CA, USA). With the unprotected column (grey dots, picture below), sequential injections of the matrix lead to a steady and irreversible increase in backpressure. Without SecurityGuard ULTRA column protection, the increase in backpressure became exponential. This increase in backpressure would eventually lead to degraded chromatography, including band broadening and possibly peak splitting. As a result, method sensitivity, quantitation, and peak identification may also be adversely affected.</p> <p></p> <p></p> <figure class="wp-block-image size-large"><a href="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/accelerated-column-lifetime-test-breakout-blog.png?ssl=1"><img data-recalc-dims="1" loading="lazy" decoding="async" width="744" height="341" data-attachment-id="12277" data-permalink="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/accelerated-column-lifetime-test-breakout-blog/" data-orig-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/accelerated-column-lifetime-test-breakout-blog.png?fit=744%2C341&ssl=1" data-orig-size="744,341" data-comments-opened="1" data-image-meta="{"aperture":"0","credit":"","camera":"","caption":"","created_timestamp":"0","copyright":"","focal_length":"0","iso":"0","shutter_speed":"0","title":"","orientation":"0"}" data-image-title="accelerated-column-lifetime-test-breakout-blog" data-image-description="" data-image-caption="" data-medium-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/accelerated-column-lifetime-test-breakout-blog.png?fit=300%2C138&ssl=1" data-large-file="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/accelerated-column-lifetime-test-breakout-blog.png?fit=744%2C341&ssl=1" src="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/accelerated-column-lifetime-test-breakout-blog.png?resize=744%2C341&ssl=1" alt="Increased HPLC column lifetime with SecurityGuard ULTRA cartridge column and holder" class="wp-image-12277" srcset="https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/accelerated-column-lifetime-test-breakout-blog.png?w=744&ssl=1 744w, https://i0.wp.com/phenomenex.blog/wp-content/uploads/2021/06/accelerated-column-lifetime-test-breakout-blog.png?resize=300%2C138&ssl=1 300w" sizes="auto, (max-width: 744px) 100vw, 744px" /></a></figure> <p></p> <p></p> <p> However, column lifetime was greatly extended by using the SecurityGuard ULTRA (black boxes, pictured above). In this case, sequential injections of the matrix still lead to an increase in pressure, but this was due to the particulates being captured in the SecurityGuard ULTRA itself, rather than in the UHPLC/HPLC column. Thus, by simply replacing the SecurityGuard ULTRA cartridge at regular intervals, backpressure returned to starting levels and effective column lifetime was greatly extended.</p> <p></p> <p></p> <p><strong>When do I replace my cartridges?</strong></p> <p></p> <p></p> <p>Visually inspect the surface of the cartridge’s packing material any time, without disturbing the packing bed. Now you can easily monitor visual contaminant build-up and change your guard cartridge before it’s too late! If your contaminants are colorless, replace the cartridge as often as needed to maintain chromatographic performance (e.g., when resolution decreases by 10% and/or when efficiency/peak widths decrease by 20%) or if the backpressure of the system increases by more than 20%.</p> <p></p> <p></p> <p><strong>What are the features that I should look for while purchasing a guard column?</strong></p> <p></p> <p></p> <p>The packing material (stationary phase) of the guard cartridge should be the same as that of the analytical column so that there is no change in the selectivity.</p> <p></p> <p></p> <p>The ID of the guard cartridge should be the same or smaller than the ID of  the analytical column to minimize increased band broadening. Always use a guard with ID closest to that of the column.</p> <p></p> <p></p> <p>The length of the guard column should be as minimal as possible to avoid additional dead volumes.</p> <p></p> <p></p> <p>The cartridges should be easy to replace whenever necessary.</p> <p></p> <p></p> <p><strong>Phenomenex offers three types of guards to cater to most of the columns that are being used.</strong></p> <p></p> <p></p> <p><a href="https://www.phenomenex.com/Products/HPLCDetail/SecurityGuard%20Standard?utm_campaign=2021%20blog%20post&utm_source=post&utm_medium=blog&utm_content=securityguard">SecurityGuard Standard</a>: Recommended for use with all non core-shell and ≥ 3 μm particle columns ((<5,000 psi /345 bar)*), they are compatible with virtually all HPLC columns.</p> <p></p> <p></p> <p><a href="https://www.phenomenex.com/Products/HPLCDetail/SecurityGuard%20ULTRA?utm_campaign=2021%20blog%20post&utm_source=post&utm_medium=blog&utm_content=securityguard">SecurityGuard ULTRA</a>:  Recommended for use with all core-shell and/or < 3 μm particle columns (< 20,000 psi / 1,378 bar)</p> <p></p> <p></p> <p><a href="https://www.phenomenex.com/Products/HPLCDetail/SecurityGuard%20Standard?utm_campaign=2021%20blog%20post&utm_source=post&utm_medium=blog&utm_content=securityguard_prep">SecurityGuard PREP</a>: Recommended for use with Prep HPLC columns with 9.0 to 49.0 mm internal diameter (ID)</p> <p></p> <div class="sharedaddy sd-sharing-enabled"><div class="robots-nocontent sd-block sd-social sd-social-icon sd-sharing"><h3 class="sd-title">Share with friends and coworkers:</h3><div class="sd-content"><ul><li class="share-linkedin"><a rel="nofollow noopener noreferrer" data-shared="sharing-linkedin-12259" class="share-linkedin sd-button share-icon no-text" href="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/?share=linkedin" target="_blank" title="Click to share on LinkedIn" ><span></span><span class="sharing-screen-reader-text">Click to share on LinkedIn (Opens in new window)</span></a></li><li class="share-facebook"><a rel="nofollow noopener noreferrer" data-shared="sharing-facebook-12259" class="share-facebook sd-button share-icon no-text" href="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/?share=facebook" target="_blank" title="Click to share on Facebook" ><span></span><span class="sharing-screen-reader-text">Click to share on Facebook (Opens in new window)</span></a></li><li class="share-twitter"><a rel="nofollow noopener noreferrer" data-shared="sharing-twitter-12259" class="share-twitter sd-button share-icon no-text" href="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/?share=twitter" target="_blank" title="Click to share on Twitter" ><span></span><span class="sharing-screen-reader-text">Click to share on Twitter (Opens in new window)</span></a></li><li class="share-jetpack-whatsapp"><a rel="nofollow noopener noreferrer" data-shared="" class="share-jetpack-whatsapp sd-button share-icon no-text" href="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/?share=jetpack-whatsapp" target="_blank" title="Click to share on WhatsApp" ><span></span><span class="sharing-screen-reader-text">Click to share on WhatsApp (Opens in new window)</span></a></li><li class="share-email"><a rel="nofollow noopener noreferrer" data-shared="" class="share-email sd-button share-icon no-text" href="mailto:?subject=%5BShared%20Post%5D%20HPLC%20Guard%20Columns%3A%20How%20They%20Work&body=https%3A%2F%2Fphenomenex.blog%2F2021%2F06%2F17%2Fhplc-guard-columns-how-they-work%2F&share=email" target="_blank" title="Click to email a link to a friend" data-email-share-error-title="Do you have email set up?" data-email-share-error-text="If you're having problems sharing via email, you might not have email set up for your browser. You may need to create a new email yourself." data-email-share-nonce="ef62f7509b" data-email-share-track-url="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/?share=email"><span></span><span class="sharing-screen-reader-text">Click to email a link to a friend (Opens in new window)</span></a></li><li class="share-end"></li></ul></div></div></div><div class='sharedaddy sd-block sd-like jetpack-likes-widget-wrapper jetpack-likes-widget-unloaded' id='like-post-wrapper-89572901-12259-674772d82af68' data-src='https://widgets.wp.com/likes/?ver=14.1-a.7#blog_id=89572901&post_id=12259&origin=phenomenex.blog&obj_id=89572901-12259-674772d82af68&n=1' data-name='like-post-frame-89572901-12259-674772d82af68' data-title='Like or Reblog'><h3 class="sd-title">Like this:</h3><div class='likes-widget-placeholder post-likes-widget-placeholder' style='height: 55px;'><span class='button'><span>Like</span></span> <span class="loading">Loading...</span></div><span class='sd-text-color'></span><a class='sd-link-color'></a></div> </div> <footer class="entry-footer"> <span class="cat-links">Posted in <a href="https://phenomenex.blog/category/featured/" rel="category tag">Featured</a>, <a href="https://phenomenex.blog/category/liquid-chromatography-lc/" rel="category tag">Liquid Chromatography (LC)</a>, <a href="https://phenomenex.blog/category/technical-tips/" rel="category tag">Technical Tips</a></span><span class="tags-links">Tagged <a href="https://phenomenex.blog/tag/guard-cartridge/" rel="tag">Guard Cartridge</a>, <a href="https://phenomenex.blog/tag/guard-column/" rel="tag">Guard Column</a>, <a href="https://phenomenex.blog/tag/security-guard/" rel="tag">security guard</a></span> </footer> </article> <div id="comments" class="comments-area"> <div id="respond" class="comment-respond"> <h3 id="reply-title" class="comment-reply-title">Leave a Reply<small><a rel="nofollow" id="cancel-comment-reply-link" href="/2021/06/17/hplc-guard-columns-how-they-work/#respond" style="display:none;">Cancel reply</a></small></h3> <form id="commentform" class="comment-form"> <iframe title="Comment Form" src="https://jetpack.wordpress.com/jetpack-comment/?blogid=89572901&postid=12259&comment_registration=0&require_name_email=1&stc_enabled=1&stb_enabled=1&show_avatars=1&avatar_default=identicon&greeting=Leave+a+Reply&jetpack_comments_nonce=938e32a048&greeting_reply=Leave+a+Reply+to+%25s&color_scheme=light&lang=en_US&jetpack_version=14.1-a.7&iframe_unique_id=1&show_cookie_consent=0&has_cookie_consent=0&is_current_user_subscribed=0&token_key=%3Bnormal%3B&sig=296a9942c0d1a32c9f224c00971e029428518d40#parent=https%3A%2F%2Fphenomenex.blog%2F2021%2F06%2F17%2Fhplc-guard-columns-how-they-work%2F" name="jetpack_remote_comment" style="width:100%; height: 430px; border:0;" class="jetpack_remote_comment" id="jetpack_remote_comment" sandbox="allow-same-origin allow-top-navigation allow-scripts allow-forms allow-popups" > </iframe>  <script> document.addEventListener('DOMContentLoaded', function () { var commentForms = document.getElementsByClassName('jetpack_remote_comment'); for (var i = 0; i < commentForms.length; i++) { commentForms[i].allowTransparency = false; commentForms[i].scrolling = 'no'; } }); </script>  </form> </div> <input type="hidden" name="comment_parent" id="comment_parent" value="" /> <p class="akismet_comment_form_privacy_notice">This site uses Akismet to reduce spam. <a href="https://akismet.com/privacy/" target="_blank" rel="nofollow noopener">Learn how your comment data is processed</a>.</p> </div> </main> </div> <div id="secondary" class="widget-area col-md-4" role="complementary"> <aside id="blog_subscription-3" class="widget widget_blog_subscription jetpack_subscription_widget"><h3 class="widget-title title-font">Subscribe!</h3> <div class="wp-block-jetpack-subscriptions__container"> <form action="#" method="post" accept-charset="utf-8" id="subscribe-blog-blog_subscription-3" data-blog="89572901" data-post_access_level="everybody" > <div id="subscribe-text"><p>Never miss another post! Enter your email address to subscribe to Science Unfiltered and receive nerdy science notifications on our newest blogs.</p> </div> <p id="subscribe-email"> <label id="jetpack-subscribe-label" class="screen-reader-text" for="subscribe-field-blog_subscription-3"> Email Address </label> <input type="email" name="email" required="required" value="" id="subscribe-field-blog_subscription-3" placeholder="Email Address" /> </p> <p id="subscribe-submit" > <input type="hidden" name="action" value="subscribe"/> <input type="hidden" name="source" value="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/"/> <input type="hidden" name="sub-type" value="widget"/> <input type="hidden" name="redirect_fragment" value="subscribe-blog-blog_subscription-3"/> <input type="hidden" id="_wpnonce" name="_wpnonce" value="bc4dfe46ee" /><input type="hidden" name="_wp_http_referer" value="/2021/06/17/hplc-guard-columns-how-they-work/" /> <button type="submit" class="wp-block-button__link" name="jetpack_subscriptions_widget" > Subscribe </button> </p> </form> <div class="wp-block-jetpack-subscriptions__subscount"> Join 826 other subscribers </div> </div> </aside><aside id="top-posts-3" class="widget widget_top-posts"><h3 class="widget-title title-font">Top Posts</h3><ul><li><a href="https://phenomenex.blog/2022/09/20/hplc_problemas/" class="bump-view" data-bump-view="tp">PROBLEMAS COMUNES DEL HPLC Y CÓMO SOLUCIONARLOS</a></li><li><a href="https://phenomenex.blog/2023/06/27/catnip-chemical-compounds/" class="bump-view" data-bump-view="tp">The Science Behind Catnip: Why Do Cats Go Crazy For It?</a></li><li><a href="https://phenomenex.blog/2022/11/21/ciencia-del-dia-de-accion-de-gracias-5-actividades-divertidas-y-faciles-para-hacer-este-dia-festivo/" class="bump-view" data-bump-view="tp">CIENCIA DEL DÍA DE ACCIÓN DE GRACIAS: 5 ACTIVIDADES DIVERTIDAS Y FÁCILES PARA HACER ESTE DÍA FESTIVO</a></li><li><a href="https://phenomenex.blog/2017/09/22/cyanide-science/" class="bump-view" data-bump-view="tp">The Science of Cyanide</a></li><li><a href="https://phenomenex.blog/2019/06/26/column-care/" class="bump-view" data-bump-view="tp">Column Care Guide: How to Clean an HPLC Column Using Reverse Flush</a></li></ul></aside><aside id="text-12" class="widget widget_text"><h3 class="widget-title title-font">Contact the Editor</h3> <div class="textwidget"><big style="font-size:18px;"><b><a href="mailto:DigitalMarketing@Phenomenex.com">DigitalMarketing@Phenomenex.com</a></b></big> </div> </aside></div> </div> </div> <div id="footer-sidebar" class="widget-area"> <div class="container"> <div class="footer-column col-md-4 col-sm-4"> <aside id="text-19" class="widget widget_text"><h3 class="widget-title title-font">Phenomenex Privacy Policy</h3> <div class="textwidget"><p><a href="https://www.phenomenex.com/Home/PrivacyPolicy">www.phenomenex.com/Home/PrivacyPolicy</a></p> </div> </aside> </div> <div class="footer-column col-md-4 col-sm-4"> <aside id="widget_contact_info-11" class="widget widget_contact_info"><h3 class="widget-title title-font">Contact Info</h3><div itemscope itemtype="http://schema.org/LocalBusiness"><div class="confit-address" itemscope itemtype="http://schema.org/PostalAddress" itemprop="address"><a href="https://maps.google.com/maps?z=16&q=411%2Bmadrid%2Bave%2Btorrance%2C%2Bca%2B90501" target="_blank" rel="noopener noreferrer">411 Madrid ave <br/>Torrance, CA 90501</a></div><div class="confit-phone"><span itemprop="telephone">310-212-0555</span></div><div class="confit-email"><a href="mailto:info@phenomenex.com">info@phenomenex.com</a></div></div></aside> </div> <div class="footer-column col-md-4 col-sm-4"> <aside id="search-9" class="widget widget_search"><h3 class="widget-title title-font">Explore Science Unfiltered</h3><form role="search" method="get" class="search-form" action="https://phenomenex.blog/"> <label> <span class="screen-reader-text">Search for:</span> <input type="search" class="search-field" placeholder="Search …" value="" name="s" /> </label> <input type="submit" class="search-submit" value="Search" /> </form></aside> </div> </div> </div>  <footer id="colophon" class="site-footer" role="contentinfo"> <div class="site-info container"> Theme Designed by <a target="blank" href="http://inkhive.com/" rel="designer">InkHive</a>. © 2024 SCIENCE UNFILTERED. All Rights Reserved. </div> </footer> </div>  <script defer id="bilmur" data-customproperties="{"woo_active":"0"}" data-provider="wordpress.com" data-service="atomic" src="https://s0.wp.com/wp-content/js/bilmur.min.js?m=202448"></script> <div class="jetpack-subscription-modal"> <div class="jetpack-subscription-modal__modal-content"> <div class="wp-block-group has-border-color jetpack-subscription-modal__modal-content-form" style="border-color:#dddddd;border-width:1px;margin-top:0;margin-bottom:0;padding:32px"><div class="wp-block-group__inner-container is-layout-flow wp-block-group-is-layout-flow"> <h2 class="wp-block-heading has-text-align-center" style="margin-top:4px;margin-bottom:10px;font-size:26px;font-style:normal;font-weight:600">Discover more from SCIENCE UNFILTERED</h2> <p class='has-text-align-center' style='margin-top:4px;margin-bottom:0px;font-size:15px'>Subscribe now to keep reading and get access to the full archive.</p> <div class="wp-block-jetpack-subscriptions__supports-newline is-style-compact wp-block-jetpack-subscriptions"> <div class="wp-block-jetpack-subscriptions__container is-not-subscriber"> <form action="https://wordpress.com/email-subscriptions" method="post" accept-charset="utf-8" data-blog="89572901" data-post_access_level="everybody" data-subscriber_email="" id="subscribe-blog-2" > <div class="wp-block-jetpack-subscriptions__form-elements"> <p id="subscribe-email"> <label id="subscribe-field-2-label" for="subscribe-field-2" class="screen-reader-text" > Type your email… </label> <input required="required" type="email" name="email" style="font-size: 16px;padding: 15px 23px 15px 23px;border-radius: 50px;border-width: 1px;" placeholder="Type your email…" value="" id="subscribe-field-2" title="Please fill in this field." /> </p> <p id="subscribe-submit" > <input type="hidden" name="action" value="subscribe"/> <input type="hidden" name="blog_id" value="89572901"/> <input type="hidden" name="source" value="https://phenomenex.blog/2021/06/17/hplc-guard-columns-how-they-work/"/> <input type="hidden" name="sub-type" value="subscribe-block"/> <input type="hidden" name="app_source" value="atomic-subscription-modal-lo"/> <input type="hidden" name="redirect_fragment" value="subscribe-blog-2"/> <input type="hidden" name="lang" value="en_US"/> <input type="hidden" id="_wpnonce" name="_wpnonce" value="bc4dfe46ee" /><input type="hidden" name="_wp_http_referer" value="/2021/06/17/hplc-guard-columns-how-they-work/" /><input type="hidden" name="post_id" value="12259"/> <button type="submit" class="wp-block-button__link" style="font-size: 16px;padding: 15px 23px 15px 23px;margin: 0; margin-left: 10px;border-radius: 50px;border-width: 1px;" name="jetpack_subscriptions_widget" > Subscribe </button> </p> </div> </form> </div> </div> <p class="has-text-align-center jetpack-subscription-modal__close" style="margin-top:20px;font-size:14px"><a href="#">Continue reading</a></p> </div></div> </div> </div> <div id="jp-carousel-loading-overlay"> <div id="jp-carousel-loading-wrapper"> <span id="jp-carousel-library-loading"> </span> </div> </div> <div class="jp-carousel-overlay" style="display: none;"> <div class="jp-carousel-container">  <div class="jp-carousel-wrap swiper-container jp-carousel-swiper-container jp-carousel-transitions" itemscope itemtype="https://schema.org/ImageGallery"> <div class="jp-carousel swiper-wrapper"></div> <div class="jp-swiper-button-prev swiper-button-prev"> <svg width="25" height="24" viewBox="0 0 25 24" fill="none" xmlns="http://www.w3.org/2000/svg"> <mask id="maskPrev" mask-type="alpha" maskUnits="userSpaceOnUse" x="8" y="6" width="9" height="12"> <path d="M16.2072 16.59L11.6496 12L16.2072 7.41L14.8041 6L8.8335 12L14.8041 18L16.2072 16.59Z" fill="white"/> </mask> <g mask="url(#maskPrev)"> <rect x="0.579102" width="23.8823" height="24" fill="#FFFFFF"/> </g> </svg> </div> <div class="jp-swiper-button-next swiper-button-next"> <svg width="25" height="24" viewBox="0 0 25 24" fill="none" xmlns="http://www.w3.org/2000/svg"> <mask id="maskNext" mask-type="alpha" maskUnits="userSpaceOnUse" x="8" y="6" width="8" height="12"> <path d="M8.59814 16.59L13.1557 12L8.59814 7.41L10.0012 6L15.9718 12L10.0012 18L8.59814 16.59Z" fill="white"/> </mask> <g mask="url(#maskNext)"> <rect x="0.34375" width="23.8822" height="24" fill="#FFFFFF"/> </g> </svg> </div> </div>  <div class="jp-carousel-close-hint"> <svg width="25" height="24" viewBox="0 0 25 24" fill="none" xmlns="http://www.w3.org/2000/svg"> <mask id="maskClose" mask-type="alpha" maskUnits="userSpaceOnUse" x="5" y="5" width="15" height="14"> <path d="M19.3166 6.41L17.9135 5L12.3509 10.59L6.78834 5L5.38525 6.41L10.9478 12L5.38525 17.59L6.78834 19L12.3509 13.41L17.9135 19L19.3166 17.59L13.754 12L19.3166 6.41Z" fill="white"/> </mask> <g mask="url(#maskClose)"> <rect x="0.409668" width="23.8823" height="24" fill="#FFFFFF"/> </g> </svg> </div>  <div class="jp-carousel-info"> <div class="jp-carousel-info-footer"> <div class="jp-carousel-pagination-container"> <div class="jp-swiper-pagination swiper-pagination"></div> <div class="jp-carousel-pagination"></div> </div> <div class="jp-carousel-photo-title-container"> <h2 class="jp-carousel-photo-caption"></h2> </div> <div class="jp-carousel-photo-icons-container"> <a href="#" class="jp-carousel-icon-btn jp-carousel-icon-info" aria-label="Toggle photo metadata visibility"> <span class="jp-carousel-icon"> <svg width="25" height="24" viewBox="0 0 25 24" fill="none" xmlns="http://www.w3.org/2000/svg"> <mask id="maskInfo" mask-type="alpha" maskUnits="userSpaceOnUse" x="2" y="2" width="21" height="20"> <path fill-rule="evenodd" clip-rule="evenodd" d="M12.7537 2C7.26076 2 2.80273 6.48 2.80273 12C2.80273 17.52 7.26076 22 12.7537 22C18.2466 22 22.7046 17.52 22.7046 12C22.7046 6.48 18.2466 2 12.7537 2ZM11.7586 7V9H13.7488V7H11.7586ZM11.7586 11V17H13.7488V11H11.7586ZM4.79292 12C4.79292 16.41 8.36531 20 12.7537 20C17.142 20 20.7144 16.41 20.7144 12C20.7144 7.59 17.142 4 12.7537 4C8.36531 4 4.79292 7.59 4.79292 12Z" fill="white"/> </mask> <g mask="url(#maskInfo)"> <rect x="0.8125" width="23.8823" height="24" fill="#FFFFFF"/> </g> </svg> </span> </a> <a href="#" class="jp-carousel-icon-btn jp-carousel-icon-comments" aria-label="Toggle photo comments visibility"> <span class="jp-carousel-icon"> <svg width="25" height="24" viewBox="0 0 25 24" fill="none" xmlns="http://www.w3.org/2000/svg"> <mask id="maskComments" mask-type="alpha" maskUnits="userSpaceOnUse" x="2" y="2" width="21" height="20"> <path fill-rule="evenodd" clip-rule="evenodd" d="M4.3271 2H20.2486C21.3432 2 22.2388 2.9 22.2388 4V16C22.2388 17.1 21.3432 18 20.2486 18H6.31729L2.33691 22V4C2.33691 2.9 3.2325 2 4.3271 2ZM6.31729 16H20.2486V4H4.3271V18L6.31729 16Z" fill="white"/> </mask> <g mask="url(#maskComments)"> <rect x="0.34668" width="23.8823" height="24" fill="#FFFFFF"/> </g> </svg> <span class="jp-carousel-has-comments-indicator" aria-label="This image has comments."></span> </span> </a> </div> </div> <div class="jp-carousel-info-extra"> <div class="jp-carousel-info-content-wrapper"> <div class="jp-carousel-photo-title-container"> <h2 class="jp-carousel-photo-title"></h2> </div> <div class="jp-carousel-comments-wrapper"> <div id="jp-carousel-comments-loading"> <span>Loading Comments...</span> </div> <div class="jp-carousel-comments"></div> <div id="jp-carousel-comment-form-container"> <span id="jp-carousel-comment-form-spinner"> </span> <div id="jp-carousel-comment-post-results"></div> <form id="jp-carousel-comment-form"> <label for="jp-carousel-comment-form-comment-field" class="screen-reader-text">Write a Comment...</label> <textarea name="comment" class="jp-carousel-comment-form-field jp-carousel-comment-form-textarea" id="jp-carousel-comment-form-comment-field" placeholder="Write a Comment..." ></textarea> <div id="jp-carousel-comment-form-submit-and-info-wrapper"> <div id="jp-carousel-comment-form-commenting-as"> <fieldset> <label for="jp-carousel-comment-form-email-field">Email (Required)</label> <input type="text" name="email" class="jp-carousel-comment-form-field jp-carousel-comment-form-text-field" id="jp-carousel-comment-form-email-field" /> </fieldset> <fieldset> <label for="jp-carousel-comment-form-author-field">Name (Required)</label> <input type="text" name="author" class="jp-carousel-comment-form-field jp-carousel-comment-form-text-field" id="jp-carousel-comment-form-author-field" /> </fieldset> <fieldset> <label for="jp-carousel-comment-form-url-field">Website</label> <input type="text" name="url" class="jp-carousel-comment-form-field jp-carousel-comment-form-text-field" id="jp-carousel-comment-form-url-field" /> </fieldset> </div> <input type="submit" name="submit" class="jp-carousel-comment-form-button" id="jp-carousel-comment-form-button-submit" value="Post Comment" /> </div> </form> </div> </div> <div class="jp-carousel-image-meta"> <div class="jp-carousel-title-and-caption"> <div class="jp-carousel-photo-info"> <h3 class="jp-carousel-caption" itemprop="caption description"></h3> </div> <div class="jp-carousel-photo-description"></div> </div> <ul class="jp-carousel-image-exif" style="display: none;"></ul> <a class="jp-carousel-image-download" href="#" target="_blank" style="display: none;"> <svg width="25" height="24" viewBox="0 0 25 24" fill="none" xmlns="http://www.w3.org/2000/svg"> <mask id="mask0" mask-type="alpha" maskUnits="userSpaceOnUse" x="3" y="3" width="19" height="18"> <path fill-rule="evenodd" clip-rule="evenodd" d="M5.84615 5V19H19.7775V12H21.7677V19C21.7677 20.1 20.8721 21 19.7775 21H5.84615C4.74159 21 3.85596 20.1 3.85596 19V5C3.85596 3.9 4.74159 3 5.84615 3H12.8118V5H5.84615ZM14.802 5V3H21.7677V10H19.7775V6.41L9.99569 16.24L8.59261 14.83L18.3744 5H14.802Z" fill="white"/> </mask> <g mask="url(#mask0)"> <rect x="0.870605" width="23.8823" height="24" fill="#FFFFFF"/> </g> </svg> <span class="jp-carousel-download-text"></span> </a> <div class="jp-carousel-image-map" style="display: none;"></div> </div> </div> </div> </div> </div> </div> <script type="text/javascript"> window.WPCOM_sharing_counts = {"https:\/\/phenomenex.blog\/2021\/06\/17\/hplc-guard-columns-how-they-work\/":12259}; </script> <link rel='stylesheet' id='all-css-0d0e64c4ac04cbb2fa23cde57c66df52' href='https://phenomenex.blog/_static/??-eJyVjcEOwjAMQ3+IEobQxgXxKWhLoymsa6IlXcXfMyQ4AzfL9rOrBpTslB00lZGzwZ1ce5xgllgSGWC/SDFKYJWVljCUHBPt0WxX/6DfQfgYvw5UjiO5gYsGFduU+eP7/40zwpAEpw0og+HC6ixbY2WqL/o6X5ru2DXt4dyenjjUZMo=' type='text/css' media='all' /> <script type="text/javascript" id="email-subscribers-js-extra"> /* <![CDATA[ */ var es_data = {"messages":{"es_empty_email_notice":"Please enter email address","es_rate_limit_notice":"You need to wait for some time before subscribing again","es_single_optin_success_message":"Successfully Subscribed.","es_email_exists_notice":"Email Address already exists!","es_unexpected_error_notice":"Oops.. Unexpected error occurred.","es_invalid_email_notice":"Invalid email address","es_try_later_notice":"Please try after some time"},"es_ajax_url":"https:\/\/phenomenex.blog\/wp-admin\/admin-ajax.php"}; /* ]]> */ </script> <script type='text/javascript' src='https://phenomenex.blog/_static/??-eJydkV1OwzAQhC+Ea9oI8YQ4i3827raO1+yuCeX0OAWJSigEIVnyg78ZzYznarCE3CKIPfXz0oAvtqENxLCbsOxOcjevQRM12aYYBN+dz9tkZJfSn8hARZlyYmp1Gz5COHt6YxeRNmnfVKlsZ0WXKd1gSyQoamtuCYvYoM7K0TFE229iDfRlIhXLL8J4NjWO1omAXvmRr0Rc4WFymI00L4HRA4vNqGBr8xnDov8BmM+3Fb9KoqZ/xaimMrwizL2sqF3UtSeaXMERRP8pv7ZZ0QqFPquplLMYfzHUl0Iqoi7dFvqes/s8T0/7x2H/cLgfhsMHUrgRFA=='></script> <script type="text/javascript" src="https://phenomenex.blog/wp-content/plugins/duracelltomi-google-tag-manager/dist/js/gtm4wp-form-move-tracker.js?ver=1.20.2" id="gtm4wp-form-move-tracker-js"></script> <script type="text/javascript" id="subscription-modal-js-js-extra"> /* <![CDATA[ */ var subscriptionData = {"homeUrl":"phenomenex.blog"}; /* ]]> */ </script> <script type='text/javascript' src='https://phenomenex.blog/_static/??-eJx9j9tOwzAMhl+IzBpdC71APEuaeMVtToodrX17XJi4QLA7W9//+XArxuUkmATkAyMyxFar3WFhwE2wJhtOCz/dHuR4pWICpdVcs2tsrrTdFUouNK9hTbkco+qmYgn7KVL6NbaENlNimJu2E9YZpkbBg89RHet3oORxe2AuKMW6FWL2LeDPRj2wTewqFaGcjFIbjBZ3/Af977Kc54CGSdCsJOCJBSwzyteD3/igCg+Zj3d1IJrOD5ex9w4tTu75dXLOdrrkPb6dX7rzOPb9MHwClIyUEA=='></script> <script type="text/javascript" src="https://stats.wp.com/e-202448.js" id="jetpack-stats-js" data-wp-strategy="defer"></script> <script type="text/javascript" id="jetpack-stats-js-after"> /* <![CDATA[ */ _stq = window._stq || []; _stq.push([ "view", JSON.parse("{\"v\":\"ext\",\"blog\":\"89572901\",\"post\":\"12259\",\"tz\":\"-8\",\"srv\":\"phenomenex.blog\",\"hp\":\"atomic\",\"ac\":\"2\",\"amp\":\"0\",\"j\":\"1:14.1-a.7\"}") ]); _stq.push([ "clickTrackerInit", "89572901", "12259" ]); /* ]]> */ </script> <script type="text/javascript" id="wp-consent-api-js-extra"> /* <![CDATA[ */ var consent_api = {"consent_type":"","waitfor_consent_hook":"","cookie_expiration":"30","cookie_prefix":"wp_consent"}; /* ]]> */ </script> <script type="text/javascript" src="https://phenomenex.blog/wp-content/plugins/wp-consent-api/assets/js/wp-consent-api.min.js?ver=1.0.7" id="wp-consent-api-js"></script> <script type="text/javascript" id="jetpack-carousel-js-extra"> /* <![CDATA[ */ var jetpackSwiperLibraryPath = {"url":"https:\/\/phenomenex.blog\/wp-content\/plugins\/jetpack\/_inc\/build\/carousel\/swiper-bundle.min.js"}; var jetpackCarouselStrings = {"widths":[370,700,1000,1200,1400,2000],"is_logged_in":"","lang":"en","ajaxurl":"https:\/\/phenomenex.blog\/wp-admin\/admin-ajax.php","nonce":"f3fd5427bd","display_exif":"1","display_comments":"1","single_image_gallery":"1","single_image_gallery_media_file":"","background_color":"black","comment":"Comment","post_comment":"Post Comment","write_comment":"Write a Comment...","loading_comments":"Loading Comments...","image_label":"Open image in full-screen.","download_original":"View full size <span class=\"photo-size\">{0}<span class=\"photo-size-times\">\u00d7<\/span>{1}<\/span>","no_comment_text":"Please be sure to submit some text with your comment.","no_comment_email":"Please provide an email address to comment.","no_comment_author":"Please provide your name to comment.","comment_post_error":"Sorry, but there was an error posting your comment. Please try again later.","comment_approved":"Your comment was approved.","comment_unapproved":"Your comment is in moderation.","camera":"Camera","aperture":"Aperture","shutter_speed":"Shutter Speed","focal_length":"Focal Length","copyright":"Copyright","comment_registration":"0","require_name_email":"1","login_url":"https:\/\/phenomenex.blog\/wp-login.php?redirect_to=https%3A%2F%2Fphenomenex.blog%2F2021%2F06%2F17%2Fhplc-guard-columns-how-they-work%2F","blog_id":"1","meta_data":["camera","aperture","shutter_speed","focal_length","copyright"]}; /* ]]> */ </script> <script type='text/javascript' src='https://phenomenex.blog/_static/??-eJyNjMESwiAMRH9IGtSqJ8dPcRCipoSUEpj+vo61V8fj7r63czZ+lIpSIXN7kCgMWLPzEa4kHm6NOIB3ZWyKvG5mLbpE0g26mf+6YYqoMDVs+HQSGMsP30XShHXxv8Hcy4cKb+eSztvT3u7s8dDbF9jLSmQ='></script> <script type="text/javascript" id="jetpack-blocks-assets-base-url-js-before"> /* <![CDATA[ */ var Jetpack_Block_Assets_Base_Url="https://phenomenex.blog/wp-content/plugins/jetpack/_inc/blocks/"; /* ]]> */ </script> <script type='text/javascript' src='https://phenomenex.blog/_static/??wp-includes/js/dist/vendor/wp-polyfill.min.js,wp-content/plugins/jetpack/_inc/blocks/subscriptions/view.js?m=1726797335'></script> <script type="text/javascript" id="sharing-js-js-extra"> /* <![CDATA[ */ var sharing_js_options = {"lang":"en","counts":"1","is_stats_active":"1"}; /* ]]> */ </script> <script type="text/javascript" src="https://phenomenex.blog/wp-content/plugins/jetpack/_inc/build/sharedaddy/sharing.min.js?ver=14.1-a.7" id="sharing-js-js"></script> <script type="text/javascript" id="sharing-js-js-after"> /* <![CDATA[ */ var windowOpen; ( function () { function matches( el, sel ) { return !! ( el.matches && el.matches( sel ) || el.msMatchesSelector && el.msMatchesSelector( sel ) ); } document.body.addEventListener( 'click', function ( event ) { if ( ! event.target ) { return; } var el; if ( matches( event.target, 'a.share-linkedin' ) ) { el = event.target; } else if ( event.target.parentNode && matches( event.target.parentNode, 'a.share-linkedin' ) ) { el = event.target.parentNode; } if ( el ) { event.preventDefault(); // If there's another sharing window open, close it. if ( typeof windowOpen !== 'undefined' ) { windowOpen.close(); } windowOpen = window.open( el.getAttribute( 'href' ), 'wpcomlinkedin', 'menubar=1,resizable=1,width=580,height=450' ); return false; } } ); } )(); var windowOpen; ( function () { function matches( el, sel ) { return !! ( el.matches && el.matches( sel ) || el.msMatchesSelector && el.msMatchesSelector( sel ) ); } document.body.addEventListener( 'click', function ( event ) { if ( ! event.target ) { return; } var el; if ( matches( event.target, 'a.share-facebook' ) ) { el = event.target; } else if ( event.target.parentNode && matches( event.target.parentNode, 'a.share-facebook' ) ) { el = event.target.parentNode; } if ( el ) { event.preventDefault(); // If there's another sharing window open, close it. if ( typeof windowOpen !== 'undefined' ) { windowOpen.close(); } windowOpen = window.open( el.getAttribute( 'href' ), 'wpcomfacebook', 'menubar=1,resizable=1,width=600,height=400' ); return false; } } ); } )(); var windowOpen; ( function () { function matches( el, sel ) { return !! ( el.matches && el.matches( sel ) || el.msMatchesSelector && el.msMatchesSelector( sel ) ); } document.body.addEventListener( 'click', function ( event ) { if ( ! event.target ) { return; } var el; if ( matches( event.target, 'a.share-twitter' ) ) { el = event.target; } else if ( event.target.parentNode && matches( event.target.parentNode, 'a.share-twitter' ) ) { el = event.target.parentNode; } if ( el ) { event.preventDefault(); // If there's another sharing window open, close it. if ( typeof windowOpen !== 'undefined' ) { windowOpen.close(); } windowOpen = window.open( el.getAttribute( 'href' ), 'wpcomtwitter', 'menubar=1,resizable=1,width=600,height=350' ); return false; } } ); } )(); /* ]]> */ </script> <iframe src='https://widgets.wp.com/likes/master.html?ver=20241127#ver=20241127&n=1' scrolling='no' id='likes-master' name='likes-master' style='display:none;'></iframe> <div id='likes-other-gravatars' class='wpl-new-layout' role="dialog" aria-hidden="true" tabindex="-1"><div class="likes-text"><span>%d</span></div><ul class="wpl-avatars sd-like-gravatars"></ul></div> <script type="text/javascript"> (function () { const iframe = document.getElementById( 'jetpack_remote_comment' ); const watchReply = function() { // Check addComment._Jetpack_moveForm to make sure we don't monkey-patch twice. if ( 'undefined' !== typeof addComment && ! addComment._Jetpack_moveForm ) { // Cache the Core function. addComment._Jetpack_moveForm = addComment.moveForm; const commentParent = document.getElementById( 'comment_parent' ); const cancel = document.getElementById( 'cancel-comment-reply-link' ); function tellFrameNewParent ( commentParentValue ) { const url = new URL( iframe.src ); if ( commentParentValue ) { url.searchParams.set( 'replytocom', commentParentValue ) } else { url.searchParams.delete( 'replytocom' ); } if( iframe.src !== url.href ) { iframe.src = url.href; } }; cancel.addEventListener( 'click', function () { tellFrameNewParent( false ); } ); addComment.moveForm = function ( _, parentId ) { tellFrameNewParent( parentId ); return addComment._Jetpack_moveForm.apply( null, arguments ); }; } } document.addEventListener( 'DOMContentLoaded', watchReply ); // In WP 6.4+, the script is loaded asynchronously, so we need to wait for it to load before we monkey-patch the functions it introduces. document.querySelector('#comment-reply-js')?.addEventListener( 'load', watchReply ); const commentIframes = document.getElementsByClassName('jetpack_remote_comment'); window.addEventListener('message', function(event) { if (event.origin !== 'https://jetpack.wordpress.com') { return; } if (!event?.data?.iframeUniqueId && !event?.data?.height) { return; } const eventDataUniqueId = event.data.iframeUniqueId; // Change height for the matching comment iframe for (let i = 0; i < commentIframes.length; i++) { const iframe = commentIframes[i]; const url = new URL(iframe.src); const iframeUniqueIdParam = url.searchParams.get('iframe_unique_id'); if (iframeUniqueIdParam == event.data.iframeUniqueId) { iframe.style.height = event.data.height + 'px'; return; } } }); })(); </script> </body> </html>