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Abstract

We report a comparison of the ionization yields provided by the most common reagents (methane, ammonia, methanol, acetonitrile and isobutane) performing in situ chemical ionization with an ion trap mass spectrometer. Four molecules were chosen in the medical field to illustrate experimental results: alprazolam, diazepam, flunitrazepam and acetaminophen. Under usual operational conditions, relative abundances of protonated ions appreciably depend on the reagents. The greatest abundance of MH⁺ ions was obtained with isobutane while observed intensities for MH⁺ ions varied from 73% for methanol and ammonia to about 23% for acetonitrile and methane. Results were rationalized comparing energies of formation of the reagent ions and storage efficiency in the trapping field.

Keywords

ion trap mass spectrometry chemical ionization reagents isobutane benzodiazepines

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References

Miller

P.E.

Denton

M.B.

Bonner

, “The quadrupole mass filter: Basic operating concepts”, J. Chem. Educ. 63, 617 (1986).

March

R.E.

, “Ion trap mass spectrometry”, Int. J. Mass Spectrom. Ion Processes 118/119, 71 (1992). doi: 10.1016/0168-1176(92)85059-9

March

R.E.

, “An Introduction to Quadrupole Ion Trap Mass Spectrometry”, J. Mass Spectrom. 32, 351 (1997). doi: 10.1002/(SICI)1096-9888(199704)32:4<351::AID-JMS512>3.0.CO;2-Y

March

R.E.

Todd

J.F.J.

, Practical Aspects of Ion-Trap Mass Spectrometry, Vol. I-III. CRC Press, Boca Raton, Florida, USA (1995).

Harrison

A.G.

, Chemical Ionization Mass Spectrometry. CRC Press, Boca Raton, Florida, USA (1992).

Lehrer

, “Improved GC/MS drug detection with chemical ionization mass spectrometry and ion trap detection”, Clin. Chem. 35, 1180 (1989).

Munson

M.S.B.

Field

F.H.

, “Chemical Ionization Mass Spectrometry. I. General Introduction”, J. Am. Chem. Soc. 88, 2621 (1966). doi: 10.1021/ja00964a001

Varian, in Advanced MS Techniques SATURN 2000 GC/MS (1996).

Bouchonnet

Libong

Sablier

, “Low pressure chemical ionization in ion trap mass spectrometry”, Eur. J. Mass Spectrom. 10(4), 509 (2004).

10.

Brodbelt

J.B.

Louris

J.N.

Cooks

R.G.

, “Chemical ionization in an ion trap mass spectrometer” Anal. Chem. 59, 1278 (1987). doi: 10.1021/ac00136a007

11.

Boswell

S.M.

Mather

R.E.

Todd

J.F.J.

, “Chemical ionisation in the ion trap: A comparative study”, Int. J. Mass Spectrom. Ion Processes 99, 139 (1990). doi: 10.1016/0168-1176(90)85026-X

12.

Johnson

J.V.

Yost

R.A.

Kelley

P.E.

Bradford

D.C.

, “Tandem-in-space and tandem-in-time mass spectrometry: Triple quadrupoles and quadrupole ion traps”, Anal. Chem. 62, 2162 (1990). doi: 10.1021/ac00219a003

13.

Bonner

R.F.

Lawson

Todd

J.F.J.

, “A low-pressure chemical ionisation source: An application of a novel type of ion storage mass spectrometer”, J. Chem. Soc. Chem. Commun. 11, 79 (1972).

14.

Eckenrode

B.A.

McLuckey

S.A.

Glish

G.L.

, “Comparison of electron ionization and chemical ionization sensitivities in an ion trap mass spectrometer”, Int. J. Mass Spectrom. Ion Processes 106, 137 (1991). doi: 10.1016/0168-1176(91)85015-E

15.

Hunter

E.P.

Lias

S.G.

, “Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update”, J. Phys. Chem. Ref. Data 413, 27 (1998).

16.

Watson

J.T.

, Introduction to mass spectrometry, 2nd Edn. Raven Press, New York, USA (1985).

17.

Teal

P.E.A.

Proveaux

A.T.

Heath

R.R.

, “Analysis and Quantitation of Insect Juvenile Hormones Using Chemical Ionization Ion-Trap Mass Spectrometry”, Anal. Biochem. 277, 206 (2000). doi: 10.1006/abio.1999.4377

18.

Gray

G.A.

, “Study of ion-molecule reactions and reaction mechanisms in acetonitrile by ion cyclotron resonance”, J. Am. Chem. Soc. 90, 6002 (1968). doi: 10.1021/ja01024a011

19.

Heerma

Sarneel

M.M.

Dijkstra

, “Structure and formation of gaseous [C₃H₄N]⁺ ions”, Org. Mass Spectrom. 21, 681 (1986).

20.

Wincel

Fokkens

R.H.

Nibbering

N.M.M.

, “On the rearrangement of the cyanomethyl cation derived from gaseous acetonitrile”, Int. J. Mass Spectrom. Ion Processes 96, 321 (1990). doi: 10.1016/0168-1176(90)85132-L

Letter: In Situ Chemical Ionization in Ion Trap Mass Spectrometry—The Beneficial Influence of Isobutane as a Reagent Gas

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