{ "id": "eptprxa4nq", "slug": "quadrupole-mass-spectrometry", "title": "Quadrupole mass spectrometry", "updated": "2026-09-30", "topic_path": [ { "id": "physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical" }, { "id": "physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry" }, { "id": "physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods" }, { "id": "physical.chemistry.methods.analytical-chemistry", "label": "Analytical chemistry", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.analytical-chemistry" }, { "id": "physical.chemistry.methods.analytical-chemistry.mass-spectrometry-methods", "label": "Mass spectrometry methods", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.analytical-chemistry.mass-spectrometry-methods" } ], "geo": [ { "id": "geo.nongeo.t1800.physical.chemistry.methods.analytical-chemistry", "label": "Non-geographic · 1800 to 1945: Analytical chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.analytical-chemistry", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1800", "label": "Non-geographic · 1800 to 1945", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800" }, { "id": "geo.nongeo.t1800.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical" }, { "id": "geo.nongeo.t1800.physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods.analytical-chemistry", "label": "Analytical chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.analytical-chemistry" } ] }, { "id": "geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry.mass-spectrometry-methods", "label": "Non-geographic · 1946 to 2000: Mass spectrometry methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry.mass-spectrometry-methods", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1946", "label": "Non-geographic · 1946 to 2000", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946" }, { "id": "geo.nongeo.t1946.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical" }, { "id": "geo.nongeo.t1946.physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry" }, { "id": "geo.nongeo.t1946.physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry.methods" }, { "id": "geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry", "label": "Analytical chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry" }, { "id": "geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry.mass-spectrometry-methods", "label": "Mass spectrometry methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1946.physical.chemistry.methods.analytical-chemistry.mass-spectrometry-methods" } ] } ], "excerpt": "Quadrupole mass spectrometry separates and detects ions by mass-to-charge ratio using oscillating radiofrequency and DC fields between four parallel rods, and anchors GC-MS, LC-MS/MS, and ICP-MS.", "snippet": "Quadrupole mass spectrometry separates and detects ions by mass-to-charge ratio using oscillating radiofrequency and DC fields between four parallel rods, and anchors GC-MS, LC-MS/MS, and ICP-MS.", "node": "physical.chemistry.methods.analytical-chemistry.mass-spectrometry-methods", "markdown": "# Quadrupole mass spectrometry\n\nQuadrupole mass spectrometry separates and detects ions by their mass-to-charge ratio (m/z) using oscillating radiofrequency (RF) and direct-current (DC) electric fields applied between four parallel rods. The rods filter out all ions except those whose m/z matches the voltages applied at a given moment, and scanning the voltages produces a mass spectrum.[1](https://www.agilent.com/Library/usermanuals/Public/G3335-90166_QQQ_Concepts.pdf) Because the analyzer is small, light, inexpensive, and scans in under 100 ms, the quadrupole mass filter has become the most common mass analyzer in use today.[2](http://people.whitman.edu/~dunnivfm/C_MS_Ebook/CH5/5_5_2.html) It anchors GC-MS, LC-MS/MS, ICP-MS, and residual gas analysis, and it operates at lower vacuum (\\( 10^{-2} \\) to \\( 10^{-3} \\) Pa) than other mass separators, which makes it well suited to interfacing with chromatography.[3](https://www.shimadzu.com.tw/service-support/technical-support/analysis-basics/lcms-intro/61intro.html)\n\n| Key fact | Value |\n|---|---|\n| What it measures | m/z, filtered by combined DC (U) and RF (\\( V \\cdot \\cos(\\omega t) \\)) fields on four rods[1](https://www.agilent.com/Library/usermanuals/Public/G3335-90166_QQQ_Concepts.pdf) |\n| Stability parameters | \\( a = 8Q \\cdot U/(m \\cdot r_{0}^{2} \\cdot \\omega^{2}) \\), \\( q = 4Q \\cdot V/(m \\cdot r_{0}^{2} \\cdot \\omega^{2}) \\); stability apex a = 0.237, q = 0.706[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/) |\n| Typical resolution | Unit mass, about ±1 Da; 0.7 Da FWHM at autotune on modern triple quadrupoles[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC11643727/) • [6](https://quantum.ee/wp-content/uploads/pdf/6420-qqq.pdf) |\n| Scan speed | Roughly 6,000 to 30,000 Da/s depending on model and year[3](https://www.shimadzu.com.tw/service-support/technical-support/analysis-basics/lcms-intro/61intro.html) • [5](https://pmc.ncbi.nlm.nih.gov/articles/PMC11643727/) |\n| Vacuum requirement | Below \\( 10^{-4} \\) hPa in the filter so ions travel without collisions[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/) |\n| Quantitation role | Triple quadrupole MRM monitors about 500 transitions per second; the dominant configuration for targeted quantitation[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC11643727/) |\n| Sensitivity trend | One-million-fold improvement in atmospheric-pressure triple quadrupole sensitivity since 1981[7](https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/rcm.9354) |\n\n## How it works\n\nBetween two pairs of rods the applied voltage is \\( U_{\\mathrm{quad}} = U + V \\cdot \\cos(\\omega t) \\), a DC portion U plus an RF portion of amplitude V and frequency \\( f = \\omega/2\\pi \\).[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/) Ion motion obeys the [Mathieu equation](https://www.edgepedia.org/mathieu-equation) (differential equation governing ion motion in oscillating fields), a six-parameter differential equation that reduces to two dimensionless parameters,[2](http://people.whitman.edu/~dunnivfm/C_MS_Ebook/CH5/5_5_2.html)\n\n\\[ a = \\frac{8QU}{m \\cdot r_{0}^{2} \\cdot \\omega^{2}}, \\qquad q = \\frac{4QV}{m \\cdot r_{0}^{2} \\cdot \\omega^{2}} \\]\n\nwhose ratio \\( a/q = 2U/V \\) is the slope of the filter's load line. Trajectories are stable only inside regions of the (a, q) plane; the load line through the first stability region's apex passes through \\( a_{\\mathrm{p}} = 0.237 \\) and \\( q_{\\mathrm{p}} = 0.706 \\).[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/) The RF field alone acts as a high-pass filter, because low-m/z ions develop large oscillation amplitudes and strike the rods; the added DC field acts as a low-pass filter that rejects high-m/z ions, so together they transmit a single m/z.[8](https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/An_Introduction_to_Mass_Spectrometry_%28Van_Bramer%29/04%3A_MASS_ANALYZERS/4.01%3A_Quadrupole) On the q axis (\\( U = 0 \\)) the RF-only filter passes all ions above a cutoff, which enables total-pressure measurement.[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/) • [9](https://www.nobelprize.org/uploads/2018/06/paul-lecture.pdf)\n\nA scan keeps \\( U/V \\) constant while ramping both voltages, moving the load line through successive stability apexes; apex voltages scale as \\( U_{p} = k_{u} \\cdot M \\cdot r_{0}^{2} \\cdot f^{2} \\), giving a linear mass scale.[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/) [Resolution](https://www.edgepedia.org/resolution) is tuned along a working line \\( U = c \\cdot V + d \\), where c sets resolution; in practice the line width ΔM is held constant, so resolving power rises in proportion to mass.[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/) • [10](https://indico.cern.ch/event/1025015/attachments/2258304/3833265/Mass_Filter%20.pdf) Real rods are cylindrical with radius \\( 1.144 \\cdot r_{0} \\) rather than the hyperbolic profile early theory assumed.[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/)\n\n## How it is done\n\nIons are usually produced by electron ionization: electrons are accelerated at 40 to 100 eV, commonly about 70 eV, near the ionization-yield maximum that lies on the order of 50 to 100 eV.[11](http://jupiter.chem.uoa.gr/thanost/papers/papers1/Vacuum_101%282014%29410.pdf) • [10](https://indico.cern.ch/event/1025015/attachments/2258304/3833265/Mass_Filter%20.pdf) With a filament heating current of 2 to 3 A and an emission current of 1 mA, sensitivity is around \\( 10^{-4} \\) A/mbar for simple gases such as nitrogen or argon.[11](http://jupiter.chem.uoa.gr/thanost/papers/papers1/Vacuum_101%282014%29410.pdf) The analyzer needs pressures below \\( 10^{-4} \\) hPa so ions cross without colliding with neutral gas.[4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/) RF-only pre-filters between the entrance lens and the RF/DC section minimize fringing-field losses, improving absolute sensitivity, peak shape, and resolution.[12](https://ardaratech.com/publications/TN_3004B_Practical%20Quadrupole%20Theory_Quadrupole%20Acceptance_2009_07_01.pdf) Detection uses a [Faraday cup](https://www.edgepedia.org/faraday-cup) or a secondary electron multiplier; the multiplier amplifies the tiny ion current typically by a factor of one million, with sensitivity up to \\( K = 10 \\ \\mathrm{A/hPa} \\).[10](https://indico.cern.ch/event/1025015/attachments/2258304/3833265/Mass_Filter%20.pdf) • [4](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/)\n\nFor triple quadrupole quantitation, the operator selects precursor and product transitions, sets dwell times, and checks the cycle time, given by cycle time = number of transitions × (dwell time + pause time), with pause time defaulting to 5 ms on most platforms. Because ion counting is Poisson-limited, relative standard deviation scales with \\( 1/\\sqrt{\\mathrm{dwell}} \\), so low-abundance analytes benefit from longer dwell times. Regulatory acceptance (ICH M10) requires calibration accuracy within ±15% of nominal (±20% at the LLOQ) for at least 75% of standards, and carryover after the upper-limit standard not exceeding 20% of the LLOQ analyte response and 5% of the internal standard response.[13](https://www.casrai.org/guides/triple-quadrupole-lc-ms-ms-configuration-quantitation-setup)\n\n## Origin\n\nThe oscillating-field filtering concept was recognized with a Nobel Prize in 1989.[10](https://indico.cern.ch/event/1025015/attachments/2258304/3833265/Mass_Filter%20.pdf) Among the developments documented in the primary literature, Ulf Von Zahn reported the monopole spectrometer in 1963 in Review of Scientific Instruments.[14](https://doi.org/10.1063/1.1718110) P. H. Dawson and N. R. Whetten reported detection of ions by ejecting them from a three-dimensional quadrupole field in 1968 in the Journal of Vacuum Science and Technology,[15](https://doi.org/10.1116/1.1492570) and John Edward Fulford and colleagues reported RF mass-selective excitation with resonant ejection in a three-dimensional trap in 1980 in the same journal.[16](https://doi.org/10.1116/1.570570) G.G. Dolnikowski and colleagues reported an ion-trapping technique in the center quadrupole of a triple quadrupole in 1988 in the International Journal of Mass Spectrometry and Ion Processes.[17](https://doi.org/10.1016/0168-1176%2888%2980001-6) U. Brinkmann reported a modified quadrupole mass filter for separating ions of higher masses with high transmission in 1972 in the International Journal of Mass Spectrometry and Ion Physics,[18](https://doi.org/10.1016/0020-7381%2872%2980041-x) and Seiji Hiroki, Tetsuya Abe, and Yoshio Murakami developed a quadrupole mass spectrometer using the second stable zone of Mathieu's diagram in 1991 in Review of Scientific Instruments.[19](https://doi.org/10.1063/1.1142377) Jae C. Schwartz, Michael W. Senko, and John E. P. Syka reported the two-dimensional linear ion trap in 2002 in the Journal of the American Society for Mass Spectrometry,[20](https://doi.org/10.1016/s1044-0305%2802%2900384-7) with mass-selective axial ejection reported by F. A. Londry and James W. Hager there in 2003[21](https://doi.org/10.1016/s1044-0305%2803%2900446-x) and a review of linear ion traps published by Donald J. Douglas, Aaron J. Frank, and Dunmin Mao in 2004 in Mass Spectrometry Reviews.[22](https://doi.org/10.1002/mas.20004) James W. Hager reported the QTrap, a configuration combining quadrupole mass filters with a linear ion trap, in 2002 in Rapid Communications in Mass Spectrometry.[23](https://doi.org/10.1002/rcm.607) Steven Wright and colleagues reported a MEMS-enabled miniature triple quadrupole in 2015 in Analytical Chemistry,[24](https://doi.org/10.1021/acs.analchem.5b00311) with a fieldable-instrument review by Dalton T. Snyder and colleagues the same year in the same journal.[25](https://doi.org/10.1021/acs.analchem.5b03070) Piotr Szyszka and colleagues reported a MEMS quadrupole mass spectrometer in 2024 in Sensors and Actuators B Chemical,[26](https://doi.org/10.1016/j.snb.2024.135712) Yu-[Peng Cheng](https://www.edgepedia.org/peng-cheng) and colleagues published a simulation study of a planar quadrupole mass filter for MEMS mass spectrometers in 2024 in the Chinese Journal of Analytical Chemistry,[27](https://doi.org/10.1016/j.cjac.2024.100364) and Xiaomin Fan and colleagues published a review of miniaturization in 2025 in Analytical Chemistry.[28](https://doi.org/10.1021/acs.analchem.5c01223)\n\n## Variants\n\nA single quadrupole offers full-scan and selected-ion monitoring (SIM); SIM is its most selective mode, but in complex matrices a single quadrupole collects unwanted isobaric masses, broadening chromatographic peaks.[29](https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/wp_65145_lc_ms_innovations_wp65145_en_0217f97f03/wp-65145-lc-ms-innovations-wp65145-en.pdf) A triple quadrupole (QqQ) places two mass filters, Q1 and Q3, around a collision cell, q2, where collision-induced dissociation creates fragment ions; two stages of mass selection give high selectivity and signal-to-noise.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC11643727/) • [29](https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/wp_65145_lc_ms_innovations_wp65145_en_0217f97f03/wp-65145-lc-ms-innovations-wp65145-en.pdf) Fixing both stages is selected reaction monitoring (SRM), the most sensitive mode; running many SRMs is MRM, and high-resolution SRM narrows Q1/Q3 widths from 0.7 Da to 0.2 Da FWHM at up to 600 SRM/s.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC11643727/) • [29](https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/wp_65145_lc_ms_innovations_wp65145_en_0217f97f03/wp-65145-lc-ms-innovations-wp65145-en.pdf) Argon collision gas gives CID efficiencies up to 65%, aided by strong focusing of product ions in the RF-only cell.[30](https://pmc.ncbi.nlm.nih.gov/articles/PMC9115313/)\n\nThe 3D ion trap applies the same physics in a different geometry: a ring electrode between two end-cap electrodes stores ions in a three-dimensional quadrupole field, normally with \\( U = 0 \\), and a mass spectrum is produced by ramping the RF voltage so ions eject in order of m/z.[3](https://www.shimadzu.com.tw/service-support/technical-support/analysis-basics/lcms-intro/61intro.html) Ion traps differ from the filter in kind: the QMF is a scanning analyzer using stable trajectories, while the trap is a sequential analyzer exploiting unstable trajectories, enabling \\(MS^n\\).[31](https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/mas.21746) Linear ion trap (LIT) trapping efficiency is about 10 times that of the 3D trap, with 20 times the charge capacity,[32](https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.813359/full) and full-scan sensitivity in LIT mode is typically more than 50 to 100 times the equivalent quadrupole-mode scan.[33](https://sciex.com/content/dam/SCIEX/pdf/tech-notes/all/QTRAP-Scan-Modes.pdf) The QTrap runs as a conventional triple quadrupole while the third quadrupole adds MS³/MRM³ and enhanced scans.[34](https://sciex.com/technology/qtrap-technology) In QTOF and quadrupole-Orbitrap hybrids, the third quadrupole is replaced by a high-resolution analyzer; parallel C-trap filling raises duty cycle above 90%, and Orbitrap detection gives mass accuracy at or below ppm levels with linear dynamic range increased by 5 orders of magnitude.[30](https://pmc.ncbi.nlm.nih.gov/articles/PMC9115313/) • [29](https://lcms.labrulez.com/labrulez-bucket-strapi-h3hsga3/wp_65145_lc_ms_innovations_wp65145_en_0217f97f03/wp-65145-lc-ms-innovations-wp65145-en.pdf) • [32](https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2021.813359/full)\n\n## Applications\n\nQuadrupoles serve as GC-MS and LC-MS analyzers, in ICP-MS, and in residual gas analysis; analytical filters are typically 200 to 300 mm long with 6 to 7 mm inscribed radius, while RGA filters are 100 to 150 mm long with about 3.5 mm radius.[11](http://jupiter.chem.uoa.gr/thanost/papers/papers1/Vacuum_101%282014%29410.pdf) In clinical laboratories, LC-MS use in endocrine testing rose from 3% to 18% of laboratories between 2011 and 2019, and biomedical studies using triple quadrupoles increased 2 to 3-fold over 2014 to 2024, with at least 84% choosing QqQ over Q-TOF for lower price and higher sensitivity in targeted analysis.[5](https://pmc.ncbi.nlm.nih.gov/articles/PMC11643727/) In ICP-MS, polyatomic interferences can be fragmented or reacted in the collision cell.[30](https://pmc.ncbi.nlm.nih.gov/articles/PMC9115313/) Spaceborne instruments use hyperbolic rods, which give near-ideal fields but are difficult and expensive to manufacture and align; the highest mass range attained by modern space instruments extends only to 500 Da, while future planetary missions require beyond 1000 Da.[35](https://www.sciencedirect.com/science/article/abs/pii/S1387380612001303)\n\n## Limitations and alternatives\n\nThe QMF is a low-resolution analyzer that cannot reliably measure accurate mass even with precision hyperbolic machining.[31](https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/mas.21746) Most quadrupole instruments are limited to unit m/z resolution and a mass range of 1000 m/z; benchtop instruments typically reach 500 m/z and research instruments up to 4000 m/z.[8](https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/An_Introduction_to_Mass_Spectrometry_%28Van_Bramer%29/04%3A_MASS_ANALYZERS/4.01%3A_Quadrupole) [Acceptance](https://www.edgepedia.org/acceptance) shrinks as resolution rises: at resolution 700 the acceptance is about 1.5% of the inscribed quadrupole area, though restricting the ion source below the acceptance yields flat-topped peaks.[12](https://ardaratech.com/publications/TN_3004B_Practical%20Quadrupole%20Theory_Quadrupole%20Acceptance_2009_07_01.pdf) Peak heights vary with mass (mass discrimination) and must be tuned, and the analyzer is not well suited to pulsed ionization.[36](https://www.as.uky.edu/sites/default/files/jeolanalyzers.pdf) Electron space charge from excessive emission current causes poor linearity at high pressure because ions become trapped in the potential well,[11](http://jupiter.chem.uoa.gr/thanost/papers/papers1/Vacuum_101%282014%29410.pdf) ion traps suffer poor dynamic range and quantitation from space charge and ion-molecule reactions,[36](https://www.as.uky.edu/sites/default/files/jeolanalyzers.pdf) and a large improvement in RF/DC quadrupole transmission is unlikely because it is fixed by the Mathieu equations.[7](https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/rcm.9354)\n\nAgainst alternatives: TOF-MS acquires up to 500 spectra/s independent of mass range, and in head-to-head GC-MS comparisons TOF covered four orders of dynamic range versus three. Hybrid QTOF and trap transmission is typically 5% or less of a QqQ in MRM mode, which explains the QqQ's dominance in quantitation.[7](https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/rcm.9354) Compared with magnetic sector instruments, the quadrupole operates at 50 to 100 V accelerating voltage rather than 5 to 60 keV, and its mass scale is linear rather than square-root.[10](https://indico.cern.ch/event/1025015/attachments/2258304/3833265/Mass_Filter%20.pdf) Since 2023, miniaturization has accelerated: monolithically 3D-printed hyperbolic QMFs for CubeSats, driven at 1 to 2.65 MHz with up to 400 \\(V_{\\text{PP}}\\) over 1 to 50 Da, resolved the Ar peak at resolution 5, each costing about US \\$100 in materials,[37](https://ieeexplore.ieee.org/stampPDF/getPDF.jsp?arnumber=10456929) and a 2026 MEMS cycloidal analyzer study argues that quadrupole and ion-trap miniaturization is constrained by RF electronics, since shrinking imposes stringent amplitude and frequency demands that increase circuit volume and power.[38](https://www.nature.com/articles/s41378-026-01409-8)\n\n## References\n\n1. [Agilent 6400 Series Triple Quad LC/MS Concepts Guide](https://www.agilent.com/Library/usermanuals/Public/G3335-90166_QQQ_Concepts.pdf)\n2. [MS Section 5.5.2: Quadrupole mass filter (Whitman College e-book chapter)](http://people.whitman.edu/~dunnivfm/C_MS_Ebook/CH5/5_5_2.html)\n3. [Introduction to LC-MS Part 6 (Shimadzu Corporation)](https://www.shimadzu.com.tw/service-support/technical-support/analysis-basics/lcms-intro/61intro.html)\n4. [Quadrupole Mass Spectrometers (QMS), Pfeiffer Vacuum knowledge book](https://www.pfeiffervacuum.com/global/en/knowledge/vacuum-technology/knowledge-book/6-mass-spectrometers-and-residual-gas-analysis/6_3_quadrupole_mass_spectrometers/)\n5. [Current Role and Potential of Triple Quadrupole Mass Spectrometry in Biomedical Research and Clinical Applications](https://pmc.ncbi.nlm.nih.gov/articles/PMC11643727/)\n6. [Agilent 6420 Triple Quadrupole LC/MS Data Sheet](https://quantum.ee/wp-content/uploads/pdf/6420-qqq.pdf)\n7. [Where have all the ions gone, long time passing? Tandem quadrupole mass spectrometers with atmospheric pressure ionization sensitivity gains since the mid-1970s. A perspective](https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/rcm.9354)\n8. [4.01: Quadrupole (chem.libretexts.org)](https://chem.libretexts.org/Bookshelves/Analytical_Chemistry/An_Introduction_to_Mass_Spectrometry_%28Van_Bramer%29/04%3A_MASS_ANALYZERS/4.01%3A_Quadrupole)\n9. [Wolfgang Paul – Nobel Lecture](https://www.nobelprize.org/uploads/2018/06/paul-lecture.pdf)\n10. [Mass Spectrometric Analysis of Gases using the Quadrupole Mass Filter (CERN lab experiment guide)](https://indico.cern.ch/event/1025015/attachments/2258304/3833265/Mass_Filter%20.pdf)\n11. [Vacuum 101(2014)410 (jupiter.chem.uoa.gr)](http://jupiter.chem.uoa.gr/thanost/papers/papers1/Vacuum_101%282014%29410.pdf)\n12. 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[Concept and simulation of a MEMS cycloidal mass analyzer (Microsystems & Nanoengineering, 2026)](https://www.nature.com/articles/s41378-026-01409-8)\n\n---\n*Topic: Encyclopedia › Physical world and mathematics › Chemistry › Chemical principles and methods › Analytical chemistry › Mass spectrometry methods*\n\n*Initially written Sep 29, 2026 · Reviewed: Sep 30, 2026 · Edited: Sep 30, 2026 · Last review: Sep 30, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [ "http://people.whitman.edu/~dunnivfm/C_MS_Ebook/CH5/5_5_2.html" ], "url": "https://www.edgepedia.org/quadrupole-mass-spectrometry", "markdown_url": "https://www.edgepedia.org/quadrupole-mass-spectrometry.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Quadrupole mass spectrometry\", Edgepedia (EdgeChat), https://www.edgepedia.org/quadrupole-mass-spectrometry. Edgepedia Community License 1.0.", "credit_md": "\"[Quadrupole mass spectrometry](https://www.edgepedia.org/quadrupole-mass-spectrometry)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/quadrupole-mass-spectrometry](https://www.edgepedia.org/quadrupole-mass-spectrometry). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Quadrupole mass spectrometry\", Edgepedia (EdgeChat), https://www.edgepedia.org/quadrupole-mass-spectrometry. Edgepedia Community License 1.0.", "speakable": "Quadrupole mass spectrometry separates and detects ions by mass-to-charge ratio using oscillating radiofrequency and DC fields between four parallel rods, and anchors GC-MS, LC-MS/MS, and ICP-MS." }