Mass spectrometry selected ion monitoring

Mass selective (selected ion monitoring) Mass spectrometry of analytes with user-selected ions fg-pg 4-5 Selective depending on chosen ions... 

Hargesheimer EE. 1984. Rapid determination of organochlorine pesticides and polychlorinated biphenyls, using selected ion monitoring mass spectrometry. J Assoc Off Anal Chem 67(6) 1067-1075. 

Poch GK, Klette KL, Anderson C. The quantitation of 2-0X0-3-hydroxy lysergic acid diethylamide (0-H-LSD) in human urine specimens, a metabolite of LSD comparative analysis using liquid chromatography-selected ion monitoring mass spectrometry and liquid chromatography-ion trap mass spectrometry. 

SY Chang, TA Moore, LL Devaud, LCE Taylor, EB Hollingsworth. Analysis of rat brain dialysate by gas chromatography-high-resolution selected-ion monitoring mass spectrometry. J Chromatogr 562 111—118, 1991. 

Shu, P-Y., S-H. Chou, and C-H. Lin. 2003. Determination of corticosterone in rat and mouse plasma by gas chromatography-selected ion monitoring mass spectrometry. Journal of Chromatography B 783 93-101. 

Arrendale, R.F., W.J. Chamberlain, O.T. Chortyk, J.L. Baker, and M.G. Stephenson Determination of tobacco-specific A-nitrosamines by capillary gas chromatography/ selected ion monitoring mass spectrometry Anal. Chem. 58 (1986) 565-568. 

Quantitative determination of selected compounds in Kentucky 1R4F Reference Cigarette smoke by multidimensional gas chromatography and selected ion monitoring-mass spectrometry J. 4246. 

DEVELOP AND ENFORCE STRICT RULES FOR REJ/ACCEPT. OF SELECTED ION MONITORING MASS SPECTROMETRY DATA... 

Determination of Serum Nadolol Levels by GLC-Selected Ion Monitoring Mass Spectrometry Comparison with a Spectrofluorometric Method J. Pharm. Sci. 67(5) 653-657 (1978) ... 

Buszka, P.M. Rose, D.L. Ozuna, G.B. and Groschen, G.Z. Determination of nanogram per liter concentration of volatile organic compounds in water by capillary gas chromatography and selected ion monitoring mass spectrometry and its use to define ground water flow directions in Edwards Aquifer, Texas. Analytical Chemistry 1995, 67, 3659-3669. 

SIM(-MS) Selected-ion monitoring (single ion monitoring) mass spectrometry... 

Selected ion monitoring mass chromatogram showing caffeine and caffeine-D3 eluted from a capillary gas chromatography column. [From D. W. Hill, B. T. McSharry, and L. S. Trzupek, Quantitative Analysis by Isotopic Dilution Using Mass Spectrometry." J. Chem. Ed. 1988, 65, 907.]... 

The sensitivity and specificity for bile acid determination can be further increased if mass spectrometry is combined with GLC. By the use of a multiple ion detector unit for selected ion monitoring (mass fragmentogra-... 

Gas Chromatography (time of Scan or selected ion flight) Mass Spectrometry, monitoring, tandem MS -M... 

Quantitative mass spectrometry, also used for pharmaceutical appHcations, involves the use of isotopicaHy labeled internal standards for method calibration and the calculation of percent recoveries (9). Maximum sensitivity is obtained when the mass spectrometer is set to monitor only a few ions, which are characteristic of the target compounds to be quantified, a procedure known as the selected ion monitoring mode (sim). When chlorinated species are to be detected, then two ions from the isotopic envelope can be monitored, and confirmation of the target compound can be based not only on the gc retention time and the mass, but on the ratio of the two ion abundances being close to the theoretically expected value. The spectrometer cycles through the ions in the shortest possible time. This avoids compromising the chromatographic resolution of the gc, because even after extraction the sample contains many compounds in addition to the analyte. To increase sensitivity, some methods use sample concentration techniques. 

Solid-phase microextraction (SPME) was used for headspace sampling. The FFA were extracted from the headspace with PA, Car/PDMS, and CW/DVB fibers. It was examined whether addition of salt (NaCl) and decreasing the pH by addition of sulphuric acid (H SO ) increased the sensitivity. FFA were analyzed using gas chromatography coupled to mass spectrometry in selected ion monitoring. 

Figure 15.8 Multidimensional GC-MS separation of urinary acids after derivatization with methyl chloroformate (a) pre-column cliromatogram after splitless injection (h) Main-column selected ion monitoring cliromatogram (mass 84) of pyroglutamic acid methyl ester. Adapted from Journal of Chromatography, B 714, M. Heil et ai, Enantioselective multidimensional gas chromatography-mass spectrometry in the analysis of urinary organic acids , pp. 119-126, copyright 1998, with permission from Elsevier Science.

Like the UV detector, the mass spectrometer may be employed as either a general detector, when full-scan mass spectra are acquired, or as a specific detector, when selected-ion monitoring (see Section 3.5.2.1) or tandem mass spectrometry (MS-MS) (see Section 3.4.2) are being used. 

In this chapter, the main aspects of mass spectrometry that are necessary for the application of LC-MS have been described. In particular, the use of selected-ion monitoring (SIM) for the development of sensitive and specific assays, and the use of MS-MS for generating structural information from species generated by soft ionization techniques, have been highlighted. Some important aspects of both qualitative and quantitative data analysis have been described and the power of using mass profiles to enhance selectivity and sensitivity has been demonstrated. 

To understand the circumstances in which particular features of mass spectrometry, such as high-resolution measurements, MS-MS and cone-voltage fragmentation, selected-ion monitoring and selected-decomposition monitoring, may be nsed to address particular analytical problems. 

Figure 5.8 Electrospray and transformed electrospray spectra of the light- and heavy-chain antibody fragments of recombinant ritnximab obtained by LC-MS analysis. Reprinted from 7. Chromatogr., A, 913, Wan, H. Z., Kaneshiro, S., Frenz, J. and Cacia, J., Rapid method for monitoring galactosylation levels dnring recombinant antibody production by electrospray mass spectrometry with selective-ion monitoring , 437-446, Copyright (2001), with permission from Elsevier Science.

Quantitative methodology employing mass spectrometry usually involves selected-ion monitoring (see Section 3.5.2.1) or selected-decomposition monitoring (see Section 3.4.2.4) in which a small number of ions or decompositions of ions specific to the compound(s) of interest are monitored. It is the role of the analyst to choose these ions/decompositions, in association with chromatographic performance, to provide sensitivity and selectivity such that when incorporated into a method the required analyses may be carried out with adequate precision and accuracy. 

To determine the residue levels of dinitroaniline herbicides, GC/NPD or GC/ECD is used in general. An aliquot of GC-ready sample solution is injected into the gas chromatograph under the conditions outlined below. Further confirmatory analysis is carried out using gas chromatography/mass spectrometry (GC/MS) in the selected-ion monitoring (SIM) mode. 

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