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Quadrupole mass analyzer

April 12, 2024

Not to be confused with Quadrupole ion trap or Radio frequency quadrupole.

In mass spectrometry, the quadrupole mass analyzer (or quadrupole mass filter) is a type of mass analyzer originally conceived[1] by Nobel laureate Wolfgang Paul and his student Helmut Steinwedel. As the name implies, it consists of four cylindrical rods, set parallel to each other.[2] In a quadrupole mass spectrometer (QMS) the quadrupole is the mass analyzer – the component of the instrument responsible for selecting sample ions based on their mass-to-charge ratio (m/z). Ions are separated in a quadrupole based on the stability of their trajectories in the oscillating electric fields that are applied to the rods.[2]

Quadrupole elements

Principle of operation edit

 
Image from US Patent "Apparatus for separating charged particles of different specific charges"[1]

The quadrupole consists of four parallel metal rods. Each opposing rod pair is connected together electrically, and a radio frequency (RF) voltage with a DC offset voltage is applied between one pair of rods and the other. Ions travel down the quadrupole between the rods. Only ions of a certain mass-to-charge ratio will reach the detector for a given ratio of voltages: other ions have unstable trajectories and will collide with the rods. This permits selection of an ion with a particular m/z or allows the operator to scan for a range of m/z-values by continuously varying the applied voltage.[2] Mathematically this can be modeled with the help of the Mathieu differential equation.[3]

 
Ion path through a quadrupole

Ideally, the rods are hyperbolic, however cylindrical rods with a specific ratio of rod diameter-to-spacing provide an easier-to-manufacture adequate approximation to hyperbolas. Small variations in the ratio have large effects on resolution and peak shape. Different manufacturers choose slightly different ratios to fine-tune operating characteristics in context of anticipated application requirements. Since the 1980s, the MAT company and subsequently Finnigan Instrument Corporation used hyperbolic rods produced with a mechanical tolerance of 0.001 mm, whose exact production process was a well-kept secret within the company.[4]

Multiple quadrupoles, hybrids and variations edit

 
Hybrid quadrupole time-of-flight mass spectrometer

A linear series of three quadrupoles is known as a triple quadrupole mass spectrometer. The first (Q1) and third (Q3) quadrupoles act as mass filters, and the middle (q2) quadrupole is employed as a collision cell. This collision cell is an RF-only quadrupole (non-mass filtering) using Ar, He, or N2 gas (~10−3 Torr, ~30 eV) for collision induced dissociation of selected parent ion(s) from Q1. Subsequent fragments are passed through to Q3 where they may be filtered or fully scanned.

This process allows for the study of fragments that are useful in structural elucidation by tandem mass spectrometry. For example, the Q1 may be set to 'filter' for a drug ion of known mass, which is fragmented in q2. The third quadrupole (Q3) can then be set to scan the entire m/z range, giving information on the intensities of the fragments. Thus, the structure of the original ion can be deduced.

The arrangement of three quadrupoles was first developed by Jim Morrison of La Trobe University in Australia for the purpose of studying the photodissociation of gas-phase ions.[5] The first triple-quadrupole mass spectrometer was developed at Michigan State University by Christie Enke and graduate student Richard Yost in the late 1970s.[6]

Quadrupoles can be used in hybrid mass spectrometers. For example, a sector instrument can be combined with a collision quadrupole and quadrupole mass analyzer to form a hybrid instrument.[7]

A mass-selecting quadrupole and collision quadrupole with time-of-flight device as the second mass selection stage is a hybrid known as a quadrupole time-of-flight mass spectrometer (QTOF MS).[8][9] Quadrupole-quadrupole-time-of-flight (QqTOF) configurations are also possible and used especially the mass spectrometry of peptides and other large biological polymers.[10][11]

A variant of the quadrupole mass analyzer called the monopole was invented by von Zahn which operates with two electrodes and generates one quarter of the quadrupole field.[12] It has one circular electrode and one V-shaped electrode. The performance is, however, lower than that of a quadrupole mass analyzer.

An enhancement to the performance of the quadrupole mass analyzer has been demonstrated to occur when a magnetic field is applied to the instrument. Manifold improvements in resolution and sensitivity have been reported for a magnetic field applied in various orientations to a QMS.[13][14]

Applications edit

These mass spectrometers excel at applications where particular ions of interest are being studied because they can stay tuned on a single ion for extended periods of time. One place where this is useful is in liquid chromatography-mass spectrometry or gas chromatography-mass spectrometry where they serve as exceptionally high specificity detectors. Quadrupole instruments are often reasonably priced and make good multi-purpose instruments. A single quadrupole mass spectrometer with an electron impact ionizer is used as a standalone analyzer in residual gas analyzers, real-time gas analyzers, plasma diagnostics and SIMS surface analysis systems.[citation needed]

See also edit

References edit

  1. ^ a b US 2939952, Paul, Wolfgang & Steinwedel, Helmut, "Apparatus for separating charged particles of different specific charges", published 1960-06-07, assigned to Wolfgang Paul 
  2. ^ a b c de Hoffmann, Edmond; Vincent Stroobant (2003). Mass Spectrometry: Principles and Applications (Second ed.). Toronto: John Wiley & Sons, Ltd. p. 65. ISBN 978-0-471-48566-7.
  3. ^ Gerald Teschl (2012). Ordinary Differential Equations and Dynamical Systems. Providence: American Mathematical Society. ISBN 978-0-8218-8328-0.
  4. ^ Brunnée, Curt (May 27, 1997). "50 Years of MAT in Bremen". Rapid Communications in Mass Spectrometry. 11 (6): 694–707. doi:10.1002/(SICI)1097-0231(199704)11:6<694::AID-RCM888>3.0.CO;2-K – via Wiley Online Library.
  5. ^ Morrison, J. D. (1991). "Personal reminiscences of forty years of mass spectrometry in Australia". Organic Mass Spectrometry. 26 (4): 183–194. doi:10.1002/oms.1210260404.
  6. ^ Yost, R. A.; Enke, C. G. (1978). (PDF). Journal of the American Chemical Society. 100 (7): 2274. doi:10.1021/ja00475a072. Archived from the original (PDF) on 2012-02-19. Retrieved 2008-12-06.
  7. ^ Glish, G.; Scott A. McLuckey; Ridley, T; Cooks, R (1982). "A new "hybrid" sector/quadrupole mass spectrometer for mass spectrometry/mass spectrometry". International Journal of Mass Spectrometry and Ion Physics. 41 (3): 157. Bibcode:1982IJMSI..41..157G. doi:10.1016/0020-7381(82)85032-8.
  8. ^ Shevchenko A; Loboda A; Shevchenko A; Ens W; Standing KG (May 2000). "MALDI quadrupole time-of-flight mass spectrometry: a powerful tool for proteomic research". Anal. Chem. 72 (9): 2132–41. doi:10.1021/ac9913659. PMID 10815976.
  9. ^ Steen H; Küster B; Mann M (July 2001). "Quadrupole time-of-flight versus triple-quadrupole mass spectrometry for the determination of phosphopeptides by precursor ion scanning". J Mass Spectrom. 36 (7): 782–90. Bibcode:2001JMSp...36..782S. doi:10.1002/jms.174. PMID 11473401.
  10. ^ Chernushevich, Igor V. (2001). "An introduction to quadrupole–time-of-flight mass spectrometry". Journal of Mass Spectrometry. 36 (8): 849–865. Bibcode:2001JMSp...36..849C. doi:10.1002/jms.207. PMID 11523084.
  11. ^ Oberacher, Herbert; Pitterl, Florian (June 2009). Fabris, Dan (ed.). "On the use of ESI-QqTOF-MS/MS for the comparative sequencing of nucleic acids". Biopolymers. 91 (6): 401–409. doi:10.1002/bip.21156. PMID 19189378.
  12. ^ U. von Zahn (1963). "Monopole Spectrometer, a New Electric Field Mass Spectrometer". Rev. Sci. Instrum. 34 (1): 1–4. Bibcode:1963RScI...34....1V. doi:10.1063/1.1718110.
  13. ^ Syed S.; Maher S.; Taylor S. (2013). "Quadrupole mass filter operation under the influence of magnetic field". Journal of Mass Spectrometry. 48 (12): 1325–1339. Bibcode:2013JMSp...48.1325S. doi:10.1002/jms.3293. PMID 24338888.
  14. ^ Maher S; Syed S; Hughes D; Gibson J; Taylor S (2013). "Mapping the stability diagram of a quadrupole mass spectrometer with a static transverse magnetic field applied". Journal of the American Society for Mass Spectrometry. 24 (8): 1307–1314. Bibcode:2013JASMS..24.1307M. doi:10.1007/s13361-013-0654-5. PMID 23720050. S2CID 45734248.

External links edit

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April 12, 2024
quadrupole, mass, analyzer, confused, with, quadrupole, trap, radio, frequency, quadrupole, mass, spectrometry, quadrupole, mass, analyzer, quadrupole, mass, filter, type, mass, analyzer, originally, conceived, nobel, laureate, wolfgang, paul, student, helmut,. Not to be confused with Quadrupole ion trap or Radio frequency quadrupole In mass spectrometry the quadrupole mass analyzer or quadrupole mass filter is a type of mass analyzer originally conceived 1 by Nobel laureate Wolfgang Paul and his student Helmut Steinwedel As the name implies it consists of four cylindrical rods set parallel to each other 2 In a quadrupole mass spectrometer QMS the quadrupole is the mass analyzer the component of the instrument responsible for selecting sample ions based on their mass to charge ratio m z Ions are separated in a quadrupole based on the stability of their trajectories in the oscillating electric fields that are applied to the rods 2 Quadrupole elements Contents 1 Principle of operation 2 Multiple quadrupoles hybrids and variations 3 Applications 4 See also 5 References 6 External linksPrinciple of operation edit nbsp Image from US Patent Apparatus for separating charged particles of different specific charges 1 The quadrupole consists of four parallel metal rods Each opposing rod pair is connected together electrically and a radio frequency RF voltage with a DC offset voltage is applied between one pair of rods and the other Ions travel down the quadrupole between the rods Only ions of a certain mass to charge ratio will reach the detector for a given ratio of voltages other ions have unstable trajectories and will collide with the rods This permits selection of an ion with a particular m z or allows the operator to scan for a range of m z values by continuously varying the applied voltage 2 Mathematically this can be modeled with the help of the Mathieu differential equation 3 nbsp Ion path through a quadrupoleIdeally the rods are hyperbolic however cylindrical rods with a specific ratio of rod diameter to spacing provide an easier to manufacture adequate approximation to hyperbolas Small variations in the ratio have large effects on resolution and peak shape Different manufacturers choose slightly different ratios to fine tune operating characteristics in context of anticipated application requirements Since the 1980s the MAT company and subsequently Finnigan Instrument Corporation used hyperbolic rods produced with a mechanical tolerance of 0 001 mm whose exact production process was a well kept secret within the company 4 Multiple quadrupoles hybrids and variations edit nbsp Hybrid quadrupole time of flight mass spectrometerA linear series of three quadrupoles is known as a triple quadrupole mass spectrometer The first Q1 and third Q3 quadrupoles act as mass filters and the middle q2 quadrupole is employed as a collision cell This collision cell is an RF only quadrupole non mass filtering using Ar He or N2 gas 10 3 Torr 30 eV for collision induced dissociation of selected parent ion s from Q1 Subsequent fragments are passed through to Q3 where they may be filtered or fully scanned This process allows for the study of fragments that are useful in structural elucidation by tandem mass spectrometry For example the Q1 may be set to filter for a drug ion of known mass which is fragmented in q2 The third quadrupole Q3 can then be set to scan the entire m z range giving information on the intensities of the fragments Thus the structure of the original ion can be deduced The arrangement of three quadrupoles was first developed by Jim Morrison of La Trobe University in Australia for the purpose of studying the photodissociation of gas phase ions 5 The first triple quadrupole mass spectrometer was developed at Michigan State University by Christie Enke and graduate student Richard Yost in the late 1970s 6 Quadrupoles can be used in hybrid mass spectrometers For example a sector instrument can be combined with a collision quadrupole and quadrupole mass analyzer to form a hybrid instrument 7 A mass selecting quadrupole and collision quadrupole with time of flight device as the second mass selection stage is a hybrid known as a quadrupole time of flight mass spectrometer QTOF MS 8 9 Quadrupole quadrupole time of flight QqTOF configurations are also possible and used especially the mass spectrometry of peptides and other large biological polymers 10 11 A variant of the quadrupole mass analyzer called the monopole was invented by von Zahn which operates with two electrodes and generates one quarter of the quadrupole field 12 It has one circular electrode and one V shaped electrode The performance is however lower than that of a quadrupole mass analyzer An enhancement to the performance of the quadrupole mass analyzer has been demonstrated to occur when a magnetic field is applied to the instrument Manifold improvements in resolution and sensitivity have been reported for a magnetic field applied in various orientations to a QMS 13 14 Applications editThese mass spectrometers excel at applications where particular ions of interest are being studied because they can stay tuned on a single ion for extended periods of time One place where this is useful is in liquid chromatography mass spectrometry or gas chromatography mass spectrometry where they serve as exceptionally high specificity detectors Quadrupole instruments are often reasonably priced and make good multi purpose instruments A single quadrupole mass spectrometer with an electron impact ionizer is used as a standalone analyzer in residual gas analyzers real time gas analyzers plasma diagnostics and SIMS surface analysis systems citation needed See also editFourier transform ion cyclotron resonance Quadrupole magnet Radio frequency quadrupole beam coolerReferences edit a b US 2939952 Paul Wolfgang amp Steinwedel Helmut Apparatus for separating charged particles of different specific charges published 1960 06 07 assigned to Wolfgang Paul a b c de Hoffmann Edmond Vincent Stroobant 2003 Mass Spectrometry Principles and Applications Second ed Toronto John Wiley amp Sons Ltd p 65 ISBN 978 0 471 48566 7 Gerald Teschl 2012 Ordinary Differential Equations and Dynamical Systems Providence American Mathematical Society ISBN 978 0 8218 8328 0 Brunnee Curt May 27 1997 50 Years of MAT in Bremen Rapid Communications in Mass Spectrometry 11 6 694 707 doi 10 1002 SICI 1097 0231 199704 11 6 lt 694 AID RCM888 gt 3 0 CO 2 K via Wiley Online Library Morrison J D 1991 Personal reminiscences of forty years of mass spectrometry in Australia Organic Mass Spectrometry 26 4 183 194 doi 10 1002 oms 1210260404 Yost R A Enke C G 1978 Selected ion fragmentation with a tandem quadrupole mass spectrometer PDF Journal of the American Chemical Society 100 7 2274 doi 10 1021 ja00475a072 Archived from the original PDF on 2012 02 19 Retrieved 2008 12 06 Glish G Scott A McLuckey Ridley T Cooks R 1982 A new hybrid sector quadrupole mass spectrometer for mass spectrometry mass spectrometry International Journal of Mass Spectrometry and Ion Physics 41 3 157 Bibcode 1982IJMSI 41 157G doi 10 1016 0020 7381 82 85032 8 Shevchenko A Loboda A Shevchenko A Ens W Standing KG May 2000 MALDI quadrupole time of flight mass spectrometry a powerful tool for proteomic research Anal Chem 72 9 2132 41 doi 10 1021 ac9913659 PMID 10815976 Steen H Kuster B Mann M July 2001 Quadrupole time of flight versus triple quadrupole mass spectrometry for the determination of phosphopeptides by precursor ion scanning J Mass Spectrom 36 7 782 90 Bibcode 2001JMSp 36 782S doi 10 1002 jms 174 PMID 11473401 Chernushevich Igor V 2001 An introduction to quadrupole time of flight mass spectrometry Journal of Mass Spectrometry 36 8 849 865 Bibcode 2001JMSp 36 849C doi 10 1002 jms 207 PMID 11523084 Oberacher Herbert Pitterl Florian June 2009 Fabris Dan ed On the use of ESI QqTOF MS MS for the comparative sequencing of nucleic acids Biopolymers 91 6 401 409 doi 10 1002 bip 21156 PMID 19189378 U von Zahn 1963 Monopole Spectrometer a New Electric Field Mass Spectrometer Rev Sci Instrum 34 1 1 4 Bibcode 1963RScI 34 1V doi 10 1063 1 1718110 Syed S Maher S Taylor S 2013 Quadrupole mass filter operation under the influence of magnetic field Journal of Mass Spectrometry 48 12 1325 1339 Bibcode 2013JMSp 48 1325S doi 10 1002 jms 3293 PMID 24338888 Maher S Syed S Hughes D Gibson J Taylor S 2013 Mapping the stability diagram of a quadrupole mass spectrometer with a static transverse magnetic field applied Journal of the American Society for Mass Spectrometry 24 8 1307 1314 Bibcode 2013JASMS 24 1307M doi 10 1007 s13361 013 0654 5 PMID 23720050 S2CID 45734248 External links editListen to this article 5 minutes source source nbsp This audio file was created from a revision of this article dated 8 September 2012 2012 09 08 and does not reflect subsequent edits Audio help More spoken articles Retrieved from https en wikipedia org w index php title Quadrupole mass analyzer amp oldid 1192112743, wikipedia, wiki, book, books, library,

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