Mass spectrometry - Technical Adjuncts

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class="md-content"> <div class="md-article-container template-desktop infinite-pagination"> <div class="infinite-scroll-container article last"> <article class="article-content container-lg qa-content px-0 pt-0 pb-40 py-lg-20 content md-expanded" data-topic-id="368325"> <div class="grid gx-0"> <div class="col-auto"> <div class="topic-left-rail md-article-drawer position-relative d-flex border-right-sm border-left-sm open"> <div class="drawer d-flex flex-column open"> <div class="left-rail-section-content"> <div class="topic-left-rail-header text-truncate bg-gray-50 position-relative text-right d-flex align-items-center"> <div class="tlr-title px-20 py-15 text-left"> <em class="material-icons text-gray-400 d-lg-none" data-icon="toc"></em> <a class="font-serif font-weight-bold text-black link-blue" href="https://www.britannica.com/science/mass-spectrometry">mass spectrometry</a> </div> <button aria-label="Close" class="js-sections-close-button btn-link btn-sm btn d-lg-none position-absolute top-0 p-10 right-0" > <em class="material-icons font-26" data-icon="close"></em> </button> </div> <div class="section-content pl-10 pr-20 pl-sm-50 pr-sm-60 pl-lg-5 pr-lg-10 pt-10 pt-lg-0 bg-gray-50 clear-catfish-ad"> <div class="toc mb-20"> <div class="font-serif font-14 font-weight-bold mx-15 mb-15 mt-20"> Table of Contents </div> <ul class="list-unstyled my-0" data-level="h1"><li data-target="#ref1"><div class="pl-25"><a class="link-gray-900 w-100" href="/science/mass-spectrometry">Introduction</a></div><div class="ml-40 toc-drawer sub-toc-drawer"></div></li><li data-target="#ref80533"><div class="d-flex align-items-center"><button class="h1-link-drawer-button btn btn-xs btn-circle d-flex rounded" type="button" aria-label="Toggle Heading"><em class="material-icons font-18" data-icon="keyboard_arrow_right"></em></button><a class="w-100 link-gray-900" href="/science/mass-spectrometry#ref80533">History</a></div><div class="ml-40 toc-drawer sub-toc-drawer"><ul class="list-unstyled" data-level="h2"><li data-target="#ref80534"><a class="w-100 link-gray-900" href="/science/mass-spectrometry#ref80534">Focusing spectroscopes</a></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80535"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-velocity-spectrometers">Ion-velocity spectrometers</a></li></ul></div></li><li data-target="#ref80536"><div class="d-flex align-items-center"><button class="h1-link-drawer-button btn btn-xs btn-circle d-flex rounded" type="button" aria-label="Toggle Heading"><em class="material-icons font-18" data-icon="keyboard_arrow_right"></em></button><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-velocity-spectrometers#ref80536">General principles</a></div><div class="ml-40 toc-drawer sub-toc-drawer"><ul class="list-unstyled" data-level="h2"><li data-target="#ref80537"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-velocity-spectrometers#ref80537">Ion sources</a><ul class="list-unstyled" data-level="h3"><li data-target="#ref80538"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-velocity-spectrometers#ref80538">Direct-current arc</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80539"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-velocity-spectrometers#ref80539">Electron bombardment</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80540"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Thermal-ionization">Thermal ionization</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80541"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Thermal-ionization#ref80541">Spark discharge</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80542"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Thermal-ionization#ref80542">Secondary-ion emission</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80543"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Thermal-ionization#ref80543">Field ionization</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80544"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Thermal-ionization#ref80544">High-frequency-produced plasma</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80545"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Thermal-ionization#ref80545">Photoionization</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80546"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Thermal-ionization#ref80546">Resonance photoionization</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80547"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Negative-ions">Negative ions</a></li></ul></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80548"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Negative-ions#ref80548">Sample introduction</a></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80549"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Negative-ions#ref80549">Ion-beam analysis</a><ul class="list-unstyled" data-level="h3"><li data-target="#ref80550"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Negative-ions#ref80550">General objectives</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80551"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Negative-ions#ref80551">Magnetic field analysis</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80552"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Electrostatic-field-analysis">Electrostatic field analysis</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80553"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Electrostatic-field-analysis#ref80553">Combined electric and magnetic field analysis</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80554"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Electrostatic-field-analysis#ref80554"><em>z</em>-axis focusing</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80555"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Electrostatic-field-analysis#ref80555">Time of flight</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80556"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-trap-methods">Ion-trap methods</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80557"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-trap-methods#ref80557">Tandem spectrometry</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80558"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-trap-methods#ref80558">Quadrupole spectrometer</a></li></ul></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80559"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-trap-methods#ref80559">Ion beam detection</a><ul class="list-unstyled" data-level="h3"><li data-target="#ref80560"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-trap-methods#ref80560">Photographic plates</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80561"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Ion-trap-methods#ref80561">Faraday cup</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80562"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Electron-multipliers">Electron multipliers</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80563"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Electron-multipliers#ref80563">Daly detector</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80564"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Electron-multipliers#ref80564">Multiple detectors</a></li></ul></li></ul></div></li><li data-target="#ref80565"><div class="d-flex align-items-center"><button class="h1-link-drawer-button btn btn-xs btn-circle d-flex rounded" type="button" aria-label="Toggle Heading"><em class="material-icons font-18" data-icon="keyboard_arrow_right"></em></button><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Important-technical-adjuncts">Important technical adjuncts</a></div><div class="ml-40 toc-drawer sub-toc-drawer"><ul class="list-unstyled" data-level="h2"><li data-target="#ref80566"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Important-technical-adjuncts#ref80566">Vacuum</a></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80567"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Important-technical-adjuncts#ref80567">Electronics</a></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80568"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Important-technical-adjuncts#ref80568">Computers</a></li></ul></div></li><li data-target="#ref80569"><div class="d-flex align-items-center"><button class="h1-link-drawer-button btn btn-xs btn-circle d-flex rounded" type="button" aria-label="Toggle Heading"><em class="material-icons font-18" data-icon="keyboard_arrow_right"></em></button><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Important-technical-adjuncts#ref80569">Applications</a></div><div class="ml-40 toc-drawer sub-toc-drawer"><ul class="list-unstyled" data-level="h2"><li data-target="#ref80570"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Important-technical-adjuncts#ref80570">Atomic</a><ul class="list-unstyled" data-level="h3"><li data-target="#ref80571"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Important-technical-adjuncts#ref80571">Atomic masses</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80572"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Important-technical-adjuncts#ref80572">Geochronology and geochemistry</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80573"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Hydrogen-carbon-nitrogen-oxygen-and-sulfur-in-nature">Hydrogen, carbon, nitrogen, oxygen, and sulfur in nature</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80574"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Hydrogen-carbon-nitrogen-oxygen-and-sulfur-in-nature#ref80574">Trace element analysis</a></li></ul></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80575"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Hydrogen-carbon-nitrogen-oxygen-and-sulfur-in-nature#ref80575">Molecular</a><ul class="list-unstyled" data-level="h3"><li data-target="#ref80576"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Hydrogen-carbon-nitrogen-oxygen-and-sulfur-in-nature#ref80576">Ion-molecule reactions</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80577"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Hydrogen-carbon-nitrogen-oxygen-and-sulfur-in-nature#ref80577">Organic chemistry</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80578"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Hydrogen-carbon-nitrogen-oxygen-and-sulfur-in-nature#ref80578">Space probes</a></li></ul><ul class="list-unstyled" data-level="h3"><li data-target="#ref80579"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Hydrogen-carbon-nitrogen-oxygen-and-sulfur-in-nature#ref80579">Leak detection</a></li></ul></li></ul></div></li><li data-target="#ref80580"><div class="d-flex align-items-center"><button class="h1-link-drawer-button btn btn-xs btn-circle d-flex rounded" type="button" aria-label="Toggle Heading"><em class="material-icons font-18" data-icon="keyboard_arrow_right"></em></button><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Accelerator-mass-spectrometry">Accelerator mass spectrometry</a></div><div class="ml-40 toc-drawer sub-toc-drawer"><ul class="list-unstyled" data-level="h2"><li data-target="#ref80581"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Accelerator-mass-spectrometry#ref80581">Development</a></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80582"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Accelerator-mass-spectrometry#ref80582">Operation of the tandem electrostatic accelerator</a></li></ul><ul class="list-unstyled" data-level="h2"><li data-target="#ref80583"><a class="w-100 link-gray-900" href="/science/mass-spectrometry/Accelerator-mass-spectrometry#ref80583">Applications</a></li></ul></div></li></ul> <a class="toc-extra-link link-gray-900" href="https://www.britannica.com/science/mass-spectrometry/additional-info">References & Edit History</a> <a class="toc-extra-link link-gray-900" href="/facts/mass-spectrometry">Quick Facts & Related Topics</a> </div> <div class="tlr-media-slider pb-10 mb-30"> <a class="section-header link-gray-900 font-serif font-14 font-weight-bold mb-10 mx-10" href="https://www.britannica.com/science/mass-spectrometry/images-videos">Images & Videos</a> <div class="slider js-slider position-relative d-inline-flex align-items-center mw-100 "> <div class="slider-container js-slider-container overflow-hidden d-flex overflow-hidden text-nowrap ml-15"> <a href="https://cdn.britannica.com/91/5691-004-D2E7DF72/electron-bombardment-ion-source-cross-section-region.jpg" data-href="/media/1/368325/3141" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/91/5691-004-D2E7DF72/electron-bombardment-ion-source-cross-section-region.jpg" alt="Figure 1: An electron bombardment ion source in cross section. An electron beam is drawn from the filament and accelerated across the region in which the ions are formed and toward the electron trap. An electric field produced by the repeller forces the ion beam from the source through the exit slit." height="50" /> </a> <a href="https://cdn.britannica.com/93/5693-004-5CA0AE48/Paths-ions-magnetic-field-plane-perpendicular-B.jpg" data-href="/media/1/368325/3137" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/93/5693-004-5CA0AE48/Paths-ions-magnetic-field-plane-perpendicular-B.jpg" alt="Figure 2: Paths of monoenergetic ions moving in a plane perpendicular to a magnetic field, passing through focal point B after originating at point A (see text)." height="50" /> </a> <a href="https://cdn.britannica.com/95/5695-004-86D5D4EC/action-field-ions-beam-electrodes-focus-point.jpg" data-href="/media/1/368325/3138" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/95/5695-004-86D5D4EC/action-field-ions-beam-electrodes-focus-point.jpg" alt="Figure 3: Focusing action of a radial electrostatic field produced by two semicylindrical charged electrodes on a monoenergetic beam of ions. The ions diverging from point A are brought to a focus at point B." height="50" /> </a> <a href="https://cdn.britannica.com/96/5696-004-DDAD36CA/Arrangement-sectors-mass-spectrometer-Mattauch-Herzog-ions-beam.jpg" data-href="/media/1/368325/3139" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/96/5696-004-DDAD36CA/Arrangement-sectors-mass-spectrometer-Mattauch-Herzog-ions-beam.jpg" alt="Figure 4: Arrangement of the electrostatic and magnetic sectors in the Mattauch-Herzog double-focusing mass spectrometer. The ions are deflected in opposite directions in the electrostatic and magnetic fields. The divergent monoenergetic beam contains two ion species of different mass-to-charge ratio. All ions are brought to a focus along the plane AB." height="50" /> </a> <a href="https://cdn.britannica.com/97/5697-004-E0FD514B/Arrangement-direction-sectors-mass-spectrometer-Nier-sector.jpg" data-href="/media/1/368325/3140" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/97/5697-004-E0FD514B/Arrangement-direction-sectors-mass-spectrometer-Nier-sector.jpg" alt="Figure 5: Arrangement of the electrostatic and magnetic sectors in the Nier double-focusing mass spectrometer. The angle of the electrostatic sector is 90° and that of the magnetic sector 60°. The direction of deflection of the ion beam is the same in both sectors." height="50" /> </a> <a href="https://cdn.britannica.com/98/5698-004-D4574C38/diagram-quadrupole-mass-spectrometer-electrodes-pairs-radio.jpg" data-href="/media/1/368325/3142" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/98/5698-004-D4574C38/diagram-quadrupole-mass-spectrometer-electrodes-pairs-radio.jpg" alt="Figure 6: Schematic diagram of a quadrupole mass spectrometer. The pairs of opposing electrodes are electrically connected to a balanced voltage source having a radio frequency component superimposed on a constant potential. Combinations of values for the amplitude and frequency exist that allow ions of a given mass from a beam of constant energy to emerge undeflected." height="50" /> </a> <a href="https://cdn.britannica.com/99/5699-004-CB000B59/spectrum-osmium-Os-recorder-trace-electron-multiplier.jpg" data-href="/media/1/368325/3143" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/99/5699-004-CB000B59/spectrum-osmium-Os-recorder-trace-electron-multiplier.jpg" alt="Figure 7: The mass spectrum of osmium. This recorder trace was obtained with an electron multiplier detecting OsO3−. The leftmost and rightmost peaks were recorded with the detector gain set at a value 100 times that used for the rest of the spectrum; this change is marked by the change in the baseline position. The small satellite peaks to the left are those of the low abundance oxygen isotopes 17O and 18O; the osmium isotopes are, from left to right, 184Os, 186Os, 188Os, 189Os, 190Os, and the satellite peaks of 192Os." height="50" /> </a> <a href="https://cdn.britannica.com/00/5700-004-86C755A2/diagram-application-accelerator-mass-spectrometer-ion-trajectories.jpg" data-href="/media/1/368325/3148" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/00/5700-004-86C755A2/diagram-application-accelerator-mass-spectrometer-ion-trajectories.jpg" alt="Figure 8: Schematic diagram showing the ion trajectories in an accelerator mass spectrometer with application to 10Be. Negative ions of BeO leave the source and are mass analyzed with 10BeO− directed into the accelerator and 9BeO− into a Faraday cup. The molecular ions are broken up by gas and a thin carbon foil in the high-voltage terminal with much of the 10Be ionized to the 3+ charge state. The emerging ions pass through a velocity selector, are again analyzed for mass, and pass to the detector. Velocity selection is attained by a magnetic field and an electric field that are orthogonal to one another and to the beam direction; they are adjusted so that no deflection takes place for ions of the desired velocity." height="50" /> </a> <a href="https://cdn.britannica.com/09/7409-004-FC74091C/Mass-spectrometry-structure-compounds-2-butanone-ions-compound.jpg" data-href="/media/1/368325/69" class="media-overlay-link d-inline-block mr-5"> <img loading="lazy" src="https://cdn.britannica.com/09/7409-004-FC74091C/Mass-spectrometry-structure-compounds-2-butanone-ions-compound.jpg" alt="mass spectrum of 2-butanone" height="50" /> </a> <a href="/video/research-fingerprints/207679" data-href="/media/1/368325/207679" class="media-overlay-link d-inline-block mr-5"> <div class="position-relative --aspect-ratio: 16/9"> <img loading="lazy" src="https://cdn.britannica.com/17/187017-138-9CF1485B/research-fingerprints.jpg?w=400&h=225&c=crop" alt="A real-life forensic technique: Aging fingerprints" class="col-100" /> <div class="btn btn-sm btn-white btn-circle position-absolute shadow" style="top: 50%; left:50%; transform: translate(-50%, -50%)"> <em class="material-icons font-14" data-icon="play_arrow" > </em> </div> </div> </a> </div> <button disabled class="prev-button js-prev-button position-absolute btn btn-circle shadow btn-blue " aria-label="Previous"> <span class="material-icons md-24" data-icon="keyboard_arrow_left"></span> </button> <button disabled class="next-button js-next-button position-absolute btn btn-circle shadow btn-blue " aria-label="Next"> <span class="material-icons md-24" data-icon="keyboard_arrow_right"></span> </button> </div> </div> <div class="mb-30 tlr-student-links"> <div class="text-gray-900 p-5 font-serif font-14 font-weight-bold mx-10 mb-10"> For Students </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/summary/mass-spectrometry"> <img loading="lazy" src="https://cdn.britannica.com/mendel-resources/3-130/images/shared/default3.png?v=3.130.14" class="default " height="200" width="200"/> </a> </div> <div class="card-body ilf-content"> <a class="font-weight-semi-bold d-block mb-5 font-16 ilf-title" href="/summary/mass-spectrometry" >mass spectrometry summary</a> </div> </div> </div> <div class="mb-30 tlr-discover"> <div class="text-gray-900 p-5 font-serif font-14 font-weight-bold mx-10 mb-10"> Discover </div> <div class="imagelink-with-image-on-the-side card card-horizontal tlr-img-with-side-link ml-15 link-gray-900 mb-10" > <div class="position-relative card-media" style="flex: 0;"> <a class="ilf-image position-relative" href="/story/pro-and-con-school-uniforms"> <img loading="lazy" src="https://cdn.britannica.com/35/230835-131-63152980/School-children-wearing-school-uniforms.jpg?w=200&h=200&c=crop" alt="Diverse elementary school children wearing school uniforms running outside of school. 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Mass spectrometry</a></li> <li><a class="external" href="https://www.cif.iastate.edu/mass-spec/ms-tutorial" target="_blank" rel="noopener ">Iowa State University - Chemical Instrumentation Facility - Mass Spectrometry Tutorial</a></li> <li><a class="external" href="https://www.academia.edu/22380179/Mass_Spectroscopy" target="_blank" rel="noopener ">Academia - Mass Spectroscopy</a></li> <li><a class="external" href="https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/Supplemental_Modules_(Analytical_Chemistry)/Instrumentation_and_Analysis/Mass_Spectrometry" target="_blank" rel="noopener ">Chemistry LibreTexts - Mass Spectrometry</a></li> <li><a class="external" href="https://www.chem.pitt.edu/facilities/mass-spectrometry/mass-spectrometry-introduction" target="_blank" rel="noopener ">University of Pittsburgh - Department of Chemistry - Mass Spectrometry Introduction</a></li> <li><a class="external" href="https://www.whitman.edu/chemistry/edusolns_software/GC_LC_CE_MS_2017/CH%205a%202017.pdf" target="_blank" rel="noopener ">Whitman College - Basic Mass Spectrometry</a></li> <li><a class="external" href="https://www.khanacademy.org/science/chemistry/x822131fc:untitled-537/mass-spectrometry/v/mass-spectrometry" target="_blank" rel="noopener ">Khan Academy - Mass spectrometry</a></li> <li><a class="external" href="https://iopscience.iop.org/article/10.1088/1742-6596/436/1/012083/pdf" target="_blank" rel="noopener ">IOPscience - Journal of Physics: Conference Series - Some interesting and exotic applications of carbon-14 dating by accelerator mass spectrometry</a></li> <li><a class="external" href="https://ecampusontario.pressbooks.pub/orgbiochemsupplement/chapter/mass-spectrometry/" target="_blank" rel="noopener ">Open Library Publishing Platform - Organic and Biochemistry Supplement to Enhanced Introductory College Chemistry - Mass Spectrometry (MS)</a></li> <li><a class="external" href="https://www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/Spectrpy/MassSpec/masspec1.htm" target="_blank" rel="noopener ">Michigan State University - Mass Spectrometry</a></li> <li><a class="external" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2642903/" target="_blank" rel="noopener ">National Center for Biotechnology Information - PubMed Central - Mass Spectrometry for Proteomics</a></li> <li><a class="external" href="https://masspec.scripps.edu/learn/ms/" target="_blank" rel="noopener nofollow">Scripps Center for Mass Spectrometry - Basics of Mass Spectrometry</a></li> </ul> </div> </div> </div> </div> </div> <div class="toc-header-marker"></div> <button class="ai-ask-button btn border-2 js-header-ai-ask-button d-none btn-sm btn-outline-red-400 border-red-400 mr-0 mr-lg-10 ml-5 ml-sm-10 ml-lg-0 p-10"> Ask the Chatbot a Question </button> <div class="caption alternate-titles">Also known as: mass spectroscopy</div> <div class="md-byline module-spacing "> <div class="font-serif font-12"> <span class="written-by text-gray-700"> Written by </span> <div class="editor-popover popover p-0"> <a class="d-block p-20 gtm-byline font-12 byline-contributor" href="/contributor/Louis-Brown/3914" > <div class="editor-title font-16 font-weight-bold">Louis Brown</div> <div class="editor-description font-12 font-serif mt-5 clamp-description text-black">Emeritus staff member, Department of Terrestrial Magnetism, Carnegie Institution of Washington, D.C.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link gtm-byline font-12 byline-contributor text-decoration-underline"> Louis Brown</span>, <div class="editor-popover popover p-0"> <a class="d-block p-20 gtm-byline font-12 byline-contributor" href="/contributor/John-Herbert-Beynon/267" > <div class="editor-title font-16 font-weight-bold">John Herbert Beynon</div> <div class="editor-description font-12 font-serif mt-5 clamp-description text-black">Royal Society Research Professor Emeritus, University College of Swansea, University of Wales. Author of <i>Mass Spectrometry and Its Application to Organic Chemistry.</i></div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link gtm-byline font-12 byline-contributor text-decoration-underline"> John Herbert Beynon</span><span class="text-gray-700 mx-5">•</span><a class="see-all border-gray-700 gtm-byline" rel="nofollow" href="https://www.britannica.com/science/mass-spectrometry/additional-info#contributors">All</a> </div> <div class="font-serif font-12 text-gray-700"> <span class="qa-fact-checked-by">Fact-checked by</span> <div class="editor-popover popover p-0"> <a class="d-block p-20 font-12" href="/editor/The-Editors-of-Encyclopaedia-Britannica/4419" > <div class="editor-title font-16 font-weight-bold">The Editors of Encyclopaedia Britannica</div> <div class="editor-description font-12 font-serif mt-5 text-black">Encyclopaedia Britannica's editors oversee subject areas in which they have extensive knowledge, whether from years of experience gained by working on that content or via study for an advanced degree. They write new content and verify and edit content received from contributors.</div> </a> <div data-popper-arrow></div> </div> <span class="btn btn-link editor-link p-0 qa-byline-link font-12 "> The Editors of Encyclopaedia Britannica</span></div> <div class="last-updated font-12 font-serif"> <span class="text-gray-700"> Last Updated: <time datetime="2024-10-18T00:00:00CDT" >Oct 18, 2024</time> •</span> <a class="byline-edit-history" href="https://www.britannica.com/science/mass-spectrometry/additional-info#history" rel="nofollow">Article History</a> </div></div> </div> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button d-none d-sm-block js-sections-inline-button module-spacing btn d-lg-none"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <div class="d-flex d-sm-none flex-row"> <button class="d-flex d-lg-none btn btn-outline-blue border rounded-sm shadow-sm mobile-toc-button gtm-mobile-toc-inline-button js-sections-inline-button module-spacing"> <em class="material-icons mr-5 ml-n10 my-n5 md-icon" data-icon="toc"></em> Table of Contents </button> <button class="ai-ask-button btn border-2 ai-ask-button btn border-2 module-spacing btn-sm js-inline-ai-ask-button btn-outline-red-400 border-red-400 p-10 ml-5"> Ask the Chatbot a Question </button> </div> <div class="js-qf-module qf-module px-40 px-sm-20 py-15 mx-auto module-spacing font-14 bg-gray-50 rounded"> <div class="facts-list mt-10"> <div class=""> <div class="js-fact mb-10 line-clamp clamp-3"> <dl> <dt>Also called: </dt> <dd>mass spectroscopy</dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> </div> <div class=""> <div class="js-fact mb-10 line-clamp clamp-3"> <dl> <dt>Key People: </dt> <dd><a href="/biography/John-Fenn" topicid="891299">John B. Fenn</a></dd> <dd><a href="/biography/Tanaka-Koichi" topicid="891322">Tanaka Koichi</a></dd> <dd><a href="/biography/Francis-William-Aston" topicid="39838">Francis William Aston</a></dd> <dd><a href="/biography/Arthur-Jeffrey-Dempster" topicid="157489">Arthur Jeffrey Dempster</a></dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> </div> <div class=""> <div class="js-fact mb-10 line-clamp clamp-3"> <dl> <dt>Related Topics: </dt> <dd><a href="/science/ion-trap-mass-spectrometry" topicid="292854">ion-trap mass spectrometry</a></dd> <dd><a href="/science/secondary-ion-mass-spectrometry" topicid="531734">secondary ion mass spectrometry</a></dd> <dd><a href="/science/resonance-ionization-mass-spectrometry" topicid="499442">resonance-ionization mass spectrometry</a></dd> <dd><a href="/science/mass-spectroscope" topicid="368354">mass spectroscope</a></dd> <dd><a href="/science/mass-spectrum" topicid="368362">mass spectrum</a></dd> </dl> <button class="js-more-btn d-none btn btn-unstyled font-12 bg-gray-50" aria-label="Toggle more/less fact data"> <em class="js-content link-blue">(Show more)</em> </button> </div> <div class="text-center"> <a class="btn btn-sm btn-link p-0" href="/facts/mass-spectrometry"> See all related content </a> </div> </div> </div> </div><span class="marker before-article"></span><span class="marker h4"></span><section data-level="1" id="ref80565">  <section data-level="2" id="ref80566"> <h2 class="h2"><span id="ref619956"></span><a href="https://www.britannica.com/technology/vacuum-technology" class="md-crosslink " data-show-preview="true">Vacuum</a></h2> <span class="marker PREMOD1 mod-inline"></span><p class="topic-paragraph">In the devices heretofore described, the presence of a good vacuum system has been assumed. Mass spectroscopy originated at about the time that <span id="ref619957"></span>high vacuum was first attained in the laboratory. High vacuum refers to a pressure low enough that the <a href="https://www.britannica.com/science/mean-free-path" class="md-crosslink autoxref " data-show-preview="true">mean free path</a> (the distance traveled between collisions) of molecules in the residual <a href="https://www.britannica.com/science/gas-state-of-matter" class="md-crosslink autoxref " data-show-preview="true">gas</a> is greater than the dimensions of the vacuum vessel. Mass spectroscopists invariably seek conditions of improved vacuum. The properties that render low pressures desirable include a reduction in the scattering of the beam in the analyzer, which causes interfering background effects and a reduction in the production of spurious beams out of the residual gases, particularly from the organic <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="compounds" href="https://www.merriam-webster.com/dictionary/compounds" data-type="MW">compounds</a> that are present. The history of vacuum techniques is varied and great and has provided present mass spectrometrists with pressures that are routinely four to five orders of magnitude lower than those first used by Thomson, Aston, and Dempster. The invention of the <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="diffusion" href="https://www.merriam-webster.com/dictionary/diffusion" data-type="MW">diffusion</a> pump by the German physicist <span id="ref619959"></span>Wolfgang Gaede in 1915, with important improvements by the American chemist <span id="ref619960"></span><a href="https://www.britannica.com/biography/Irving-Langmuir" class="md-crosslink " data-show-preview="true">Irving Langmuir</a> shortly thereafter, freed mass spectroscopy from the severe limitations of poor vacuum. During the 1960s diffusion pumps began to be replaced by ion-getter pumps, with turbomolecular pumps becoming common in the 1980s.</p><span class="marker MOD1 mod-inline"></span> </section> <section data-level="2" id="ref80567"> <h2 class="h2"><span id="ref619961"></span><a href="https://www.britannica.com/technology/electronic-system" class="md-crosslink ">Electronics</a></h2> <span class="marker PREMOD2 mod-inline"></span><p class="topic-paragraph">The operation of a mass <a href="https://www.britannica.com/science/spectrometer" class="md-crosslink autoxref " data-show-preview="true">spectrometer</a> depends on elaborate electronic equipment: <a href="https://www.britannica.com/science/ion-physics" class="md-crosslink autoxref " data-show-preview="true">ion</a> sources require extremely stable power supplies, magnets need instruments for measuring the <a href="https://www.britannica.com/science/magnetic-field" class="md-crosslink autoxref " data-show-preview="true">magnetic field</a> and controlling the <a href="https://www.britannica.com/science/electric-current" class="md-crosslink autoxref " data-show-preview="true">current</a> supply for the coils, detectors use a variety of power supplies and amplifiers, and general operation requires electronic <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="auxiliary" href="https://www.merriam-webster.com/dictionary/auxiliary" data-type="MW">auxiliary</a> equipment. The rapid increase in the use of mass spectrometers following <a href="https://www.britannica.com/event/World-War-II" class="md-crosslink autoxref " data-show-preview="true">World War II</a> can likely be attributed in part to the large number of physicists who had gained electronic training during the war, many of whom had utilized mass spectroscopy during that conflict to monitor <a href="https://www.britannica.com/science/uranium" class="md-crosslink autoxref " data-show-preview="true">uranium</a> <a href="https://www.britannica.com/science/isotopic-fractionation" class="md-crosslink autoxref " data-show-preview="true">isotope separation</a> and to analyze aviation gasoline.</p><span class="marker MOD2 mod-inline"></span> </section> <section data-level="2" id="ref80568"> <h2 class="h2"><span id="ref619962"></span><a href="https://www.britannica.com/technology/computer" class="md-crosslink " data-show-preview="true">Computers</a></h2> <span class="marker PREMOD3 mod-inline"></span><p class="topic-paragraph">The introduction of small computers for laboratory work during the 1960s altered entirely the manner in which mass spectrometry was performed and widened its applications to an extraordinary degree. Computers were interfaced with spectrometers, making it possible to repeat a measurement schedule on a steady basis and record the <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="data" href="https://www.britannica.com/dictionary/data" data-type="EB">data</a> acquired. In organic analysis the computer was programmed to store the spectra of thousands of compounds, allowing rapid identification of the substance under study. Users soon devised ways by which the answers to their questions came within minutes after the conclusion of the analysis.</p><span class="marker MOD3 mod-inline"></span> </section> </section> <span class="marker h5"></span><section data-level="1" id="ref80569"> <h2 class="h1">Applications</h2> <section data-level="2" id="ref80570"> <h2 class="h2"><span id="ref619964"></span><a href="https://www.britannica.com/science/atom" class="md-crosslink " data-show-preview="true">Atomic</a></h2> <section data-level="3" id="ref80571"> <h2 class="h3"><span id="ref619963"></span><a href="https://www.britannica.com/science/atomic-mass" class="md-crosslink " data-show-preview="true">Atomic masses</a></h2> <span class="marker PREMOD4 mod-inline"></span><p class="topic-paragraph">The discovery of <span id="ref619965"></span><a href="https://www.britannica.com/science/isotope" class="md-crosslink " data-show-preview="true">isotopes</a> with the first mass spectrograph answered the question about the integer value of atoms only to a crude level of accuracy and made all too clear the need for more accurate mass determinations. These were first undertaken by Aston and repeated with increasing precision by succeeding generations. The first data showed slight <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="deviations" href="https://www.britannica.com/dictionary/deviations" data-type="EB">deviations</a> from an integer law but also showed a quasi-systematic variation as a function of <a href="https://www.britannica.com/science/atomic-number" class="md-crosslink autoxref " data-show-preview="true">atomic number</a>. In the early 1930s these data explained the energies of nuclear reactions then being observed through the mass-energy relation that had been given two decades earlier by the <a href="https://www.britannica.com/science/special-relativity" class="md-crosslink autoxref " data-show-preview="true">special theory</a> of relativity. Since that time mass spectroscopy and <span id="ref619966"></span><a href="https://www.britannica.com/science/nuclear-physics" class="md-crosslink ">nuclear physics</a> have combined to determine isotopic masses to a high degree of accuracy. The mass unit now used is defined so that the mass of the carbon-12 isotope is exactly 12 atomic mass units (amu). Nuclear theory is continually tested in its ability to reproduce the observed values. Indeed, these masses provide an early and critical test of nuclear models. Mass spectrometry has been closely associated with nuclear physics since its beginning. A mass spectrometer is frequently found in some form as a part of nuclear experiments to identify reaction products. Large mass spectrometers are employed as isotope separators and are capable of producing weighable amounts of selected stable isotopes that have valuable <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="analytical" href="https://www.merriam-webster.com/dictionary/analytical" data-type="MW">analytical</a> applications. They are used for labeling compounds so that they can be traced through various chemical, physical, and environmental processes without the problems created by radioisotope tracers. Analysis is, of course, performed by mass spectrometer. In addition, nuclear reactions often produce extremely small amounts of radioactive products, which cannot easily be manipulated by normal chemical procedures. In such cases, stable isotopes of the product are added to the radioactive element, thereby increasing the concentration so that it falls within the range of the <a href="https://www.britannica.com/science/scientific-method" class="md-crosslink autoxref " data-show-preview="true">analytical method</a>. These enriched isotopes are <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="indispensable" href="https://www.britannica.com/dictionary/indispensable" data-type="EB">indispensable</a> for research in nuclear physics.</p><span class="marker MOD4 mod-inline"></span> </section> <section data-level="3" id="ref80572"> <h2 class="h3"><span id="ref619968"></span><a href="https://www.britannica.com/science/geochronology" class="md-crosslink " data-show-preview="true">Geochronology</a> and <span id="ref619969"></span><a href="https://www.britannica.com/science/geochemistry" class="md-crosslink " data-show-preview="true">geochemistry</a></h2> <span class="marker PREMOD5 mod-inline"></span><p class="topic-paragraph">The early studies of the <span id="ref619970"></span><a href="https://www.britannica.com/science/radioactivity" class="md-crosslink " data-show-preview="true">radioactive decay</a> of uranium and thorium into lead caused the British physicist <a href="https://www.britannica.com/biography/Ernest-Rutherford" class="md-crosslink autoxref " data-show-preview="true">Ernest Rutherford</a> to suggest that this process could be used to determine the age of rocks and consequently of the Earth by observing the amount of helium retained by a rock relative to its uranium and thorium contents. Mass spectrometers capable of measuring <span id="ref619972"></span><a href="https://www.britannica.com/science/isotopic-abundance" class="md-crosslink ">isotopic ratios</a> allow the <a class="md-dictionary-link md-dictionary-tt-off mw" data-term="composition" href="https://www.merriam-webster.com/dictionary/composition" data-type="MW">composition</a> of elements to be determined in which one or more isotopes result from radioactive decay. The age of the rock from which the element has been obtained can be determined if the amount of the parent element can be measured and certain requirements on the environmental history of the rock are met (see <a href="https://www.britannica.com/science/dating-geochronology/Geologic-column-and-its-associated-time-scale#ref69755" class="md-crosslink " data-show-preview="true">dating: Absolute dating</a>).</p><div class="module-spacing"> </div><span class="marker MOD5 mod-inline"></span> <span class="marker PREMOD6 mod-inline"></span><p class="topic-paragraph">The <span id="ref619973"></span><a href="https://www.britannica.com/science/Earths-crust" class="md-crosslink ">Earth’s</a> crust is generally richer in <span id="ref619975"></span><a href="https://www.britannica.com/science/oxygen-18" class="md-crosslink ">oxygen-18</a> (<sup>18</sup>O) than is the mantle, as a result of the reaction of these upper-layer rocks with the hydrosphere and atmosphere. This fact allows oxygen-18 to be used to assess the degree to which <a class="md-dictionary-link md-dictionary-tt-off eb" data-term="ascending" href="https://www.britannica.com/dictionary/ascending" data-type="EB">ascending</a> magmas have incorporated crustal rocks as they rise to the surface. The use of isotopes has proved especially valuable in understanding the origin and nature of the <a href="https://www.britannica.com/science/solar-system" class="md-crosslink autoxref " data-show-preview="true">solar system</a>. A great body of evidence now suggests that <span id="ref619976"></span><a href="https://www.britannica.com/science/meteorite" class="md-crosslink " data-show-preview="true">meteorites</a> are objects that solidified very early in the history of the solar system. Extinct radioactivities of elements with various half-lives have been identified that set limits on the time between the synthesis of the elements and their condensation. (Extinct radioactivities are nuclides that have nearly completely decayed into their daughter elements.) An example is the excess of magnesium-26 (<sup>26</sup>Mg) found in primitive meteorites that resulted from the decay of aluminum-26 (<sup>26</sup>Al), which has a 720,000-year half-life.</p><span class="marker MOD6 mod-inline"></span> </section> </section></section><span class="marker end-of-content"></span><span class="marker after-article"></span></div> <div id="chatbot-root"></div> </div> </div> </div> <div class="ai-dialog-placeholder"></div> </div> </div> <aside class="col-md-da-320"></aside> </div> </div> </div> </div> </article></div> </div></div> </div> </main> <div id="md-footer"></div> <noscript><iframe src="//www.googletagmanager.com/ns.html?id=GTM-5W6NC8" height="0" width="0" style="display:none;visibility:hidden"></iframe></noscript> <script type="text/javascript" id="_informizely_script_tag"> var IzWidget = IzWidget || {}; (function (d) { var scriptElement = d.createElement('script'); scriptElement.type = 'text/javascript'; scriptElement.async = true; scriptElement.src = "https://insitez.blob.core.windows.net/site/f780f33e-a610-4ac2-af81-3eb184037547.js"; var node = d.getElementById('_informizely_script_tag'); node.parentNode.insertBefore(scriptElement, node); } )(document); </script>  <script> window.ap3c = window.ap3c || {}; var ap3c = window.ap3c; ap3c.cmd = ap3c.cmd || []; ap3c.cmd.push(function() { ap3c.init('ZO4siT4cLwnykPnzZWJtd3Byb2Q', 'https://engage.email.britannica.com/'); ap3c.track({v: 0}); }); ap3c.activity = function(act) { ap3c.act = (ap3c.act || []); ap3c.act.push(act); }; var s, t; s = document.createElement('script'); s.type = 'text/javascript'; s.src = "https://engage.email.britannica.com/app.js"; t = document.getElementsByTagName('script')[0]; t.parentNode.insertBefore(s, t); </script> <script class="marketing-page-info" type="application/json"> {"pageType":"Topic","templateName":"DESKTOP","pageNumber":8,"pagesTotal":10,"pageId":368325,"pageLength":1038,"initialLoad":true,"lastPageOfScroll":false} </script> <script class="marketing-content-info" type="application/json"> [] </script> <script src="https://cdn.britannica.com/mendel-resources/3-130/js/libs/jquery-3.5.0.min.js?v=3.130.14"></script> <script type="text/javascript" data-type="Init Mendel Code Splitting"> (function() { $.ajax({ dataType: 'script', cache: true, url: 'https://cdn.britannica.com/mendel-resources/3-130/dist/topic-page.js?v=3.130.14' }); })(); </script> <script class="analytics-metadata" type="application/json"> {"leg":"B","adLeg":"B","userType":"ANONYMOUS","pageType":"Topic","pageSubtype":null,"articleTemplateType":"PAGINATED","gisted":false,"pageNumber":8,"hasSummarizeButton":false,"hasAskButton":false} </script> <script type="text/javascript"> EBStat={accountId:-1,hostnameOverride:'webstats.eb.com',domain:'www.britannica.com', json:''}; </script> <script type="text/javascript"> ( function() { $.ajax( { dataType: 'script', cache: true, url: '//www.britannica.com/webstats/mendelstats.js?v=1' } ) .done( function() { try {writeStat(null,EBStat);} catch(err){} } ); })(); </script> <div id="bc-fixed-dialogue"></div> </body> </html>

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Mass spectrometry - Technical Adjuncts | Britannica