Ionization, chemical tandem mass spectrometry

Peake, D.A. Gross, M.L. Iron(I) Chemical Ionization and Tandem Mass Spectrometry for Locating Double Bonds. Anal. Chem. 1985,57, 115-120. 

Choi, M.H. Chung, B.C. Kim, M. Choi, J. Kim, Y. Determination of 4 anabolic steroid metabolites by gas chromatography/mass spectrometry with negative ion chemical ionization and tandem mass spectrometry. Rapid Commun. Mass. Spectrom. 1998, 12, 1749-1755. 

Gurarini, A., G. Guglielmetti, M. Vincenti, P. Guarda, and G. Marchionni. 1993. Characterization of perfluoropolyethers by desorption chemical ionization and tandem mass spectrometry. Anal. Chem. 65 970-975. 

Kampo medicines in which A.fangchi root or A. manshuriensis stem may be misused [492], Moreover, LC-PDA and LC-EIMS detection methods both were effective in distinguishing AAI (5) and AAII (5) peaks by their spectra. Very recently, we have reported the extensive analysis of aristolochic acids and aristolactams in the various Chinese medicinal plants and crude drugs using different techniques. A method has been developed using reversed phase liquid chromatography coupled with atmospheric pressure chemical ionization (APCI) tandem mass spectrometry under the positive ion detection mode [LC/(+)APCI/MS/MS] to determine the amount of AA-1(5) in Xinxin, a traditional Chinese medicine that originate from nine Asarum species... 

Recently, Blount et al. (2000) summarized a methodology to detect di- -butyl phthalate metabolites in urine. In humans or animals, di- -butyl phthalate is metabolized to mono- -butyl phthalate and oxidative products, which are excreted through the urine and feces. Human urine samples are processed by P-glucuronidase hydrolysis (to release the mono phthalate ester) followed by solid-phase extraction. The eluate is concentrated mono- -butyl phthalate is chromatographically resolved by reverse-phase HPLC, detected by negative ion atmospheric pressure chemical ionization (APCI) tandem mass spectrometry, and quantified by isotope dilution. 

Hsieh et al. (2006a) demonstrated the use of packed-column supercritical fluid chromatography (SFC) combined with atmospheric pressure chemical ionization (APCI)—tandem mass spectrometry (MS/MS) for the analysis of metabolic stability samples. For the SFC step, the mobile phase is liquid carbon dioxide with some organic modifiers added to adjust the retention time of the analytes. In this report, the primary organic modifier was methanol, and the authors described how the percentage of methanol in the mobile phase varied the retention of the analytes and affected the relative response of the test compounds in the APCI source. The authors also demonstrated that the results obtained by the SFC—APCI—MS/MS assay were equivalent to those obtained by a conventional HPLC—APCI—MS/MS assay, as shown in Figure 12.3. 

In principle however, this method should be portable to other mass spectrometer systems capable of chemical ionization and tandem mass spectrometry. An [M+54] ion was reported using atmospheric pressure chemical ionization (APCI) with a predominantly acetonitrile solvent while analyzing extremely long-chain polyunsaturated fatty acids (16). Such an observation is promising for the use of this method for the analysis of low- or nonvolatile lipids, such as triglycerides and phospholipids. 

Perr, J.M., et al. (2005) Gas chromatography positive chemical ionization and tandem mass spectrometry for the analysis of organic high explosives. Talanta, 67, 430 36. 

Perfluoroethylenes have been characterized by desorption chemical ionization and tandem mass spectrometry Fourier transform ion cyclotron resonance mass spectroscopy has also been applied to the identification of polymers, eg. polyethylene glycols. Comparative complimentary plasma desorption mass spectrometry/secondary ion mass spectrometry has been applied to the identification of oligomers of various polymers including polyethylene glycol, polytetrafluoroethylene, polycarbonate, polyacrylates, polyethylene terephthalate and siloxanes. ... 

Some methods for the isolation, detection, and characterization of swainso-nine (378) require mention. A novel analytical procedure based on small-scale hquid—hquid extraction of dried plant material, isolation by extraction with a cation-exchange resin, and quantitation by reversed-phase HPLC coupled to atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (LC-MS/MS) was devised to ewiluate the distribution of swainsonine in populations of several North American locoweeds of the genus Oxytropis the limit of detection was about 0.001% in dry plant material, which is at the... 

Until 1981, mass spectrometry was limited, generally, to the analysis of volatile, relatively low-molecular-mass samples and was difficult to apply to nonvolatile peptides and proteins without first cutting them chemically into smaller volatile segments. During the past decade, the situation has changed radically with the advent of new ionization techniques and the development of tandem mass spectrometry. Now, the mass spectrometer has a well-deserved place in any laboratory interested in the analysis of peptides and proteins. 

An on-line chromatography/atmospheric pressure chemical ionization tandem mass spectrometry (LC-APCI/MS/MS) methods was developed for rapid screen of pharmacokinetics of different drugs, including 5 (98RCM1216). The electron impact mass spectrum of 5 and ethyl 9,10-difluoro-3-methyl-7-oxo-2,3-dihydro-7Ff-pyrido[l,2,3- fe]-l,4-benzoxazine-6-carboxylate was reported (97MI28). Electron impact/Fourier transform... 

See footnote cto Table3 LC/PB/MS = hquid chromatography/particle beam mass spectrometry LC/APcl/ESl-MS/MS = liquid chromtography/atmospheric pressure chemical ionization/electrospray ionization tandem mass spectrometry LC/FTIR = Fourier transform infrared LC/TSP-MS/MS = liquid chromatography/thermospray tandem mass spectrometry LC/TSP-MS = liquid chromatography/thermospray mass spectrometry. 

More recently, liquid chromatography/mass spectrometry (LC/MS) and liquid chromatography/tandem mass spectrometry (LC/MS/MS) have been evaluated as possible alternative methods for carfentrazone-ethyl compounds in crop matrices. The LC/MS methods allow the chemical derivatization step for the acid metabolites to be avoided, reducing the analysis time. These new methods provide excellent sensitivity and method recovery for carfentrazone-ethyl. However, the final sample extracts, after being cleaned up extensively using three SPE cartridges, still exhibited ionization suppression due to the matrix background for the acid metabolites. Acceptable method recoveries (70-120%) of carfentrazone-ethyl metabolites have not yet been obtained. 

Homish, R. E. and Wiest, J. R., Quantitation of spectinomycin residues in bovine tissues by ion-exchange high-performance liquid chromatography with post-column derivatization and confirmation by reversed-phase high performance chromatography-atmospheric pressure chemical ionization tandem mass spectrometry, /. Chromatogr. A, 812, 123, 1998. 

A different strategy has been applied in our work, that emphasizes the importance of DNA stability on hole transfer within double-stranded DNA. This work is based on determination of the overall yield of oxidized nucleosides that arise from the conversion of initially generated purine and pyrimidine radical cations within DNA exposed to two-photon UVC laser pulses. On the one hand, this work benefits from the excellent current knowledge of chemical reactions involving the radical cations of DNA bases, and on the other hand, from major analytical improvements that include recent availability of the powerful technique of high performance liquid chromatography-electrospray ionization-tandem mass spectrometry (CLHP-ESI-MS/MS) [16-18]. 

McClure, TD and Liebler, DC, 1995. Electron capture negative chemical ionization mass spectrometry and tandem mass-spectrometry analysis of beta-carotene, alpha-tocopherol and their oxidation products. J Mass Spectrom 30, 1480-1488. 

For confirmatory assay, liquid chromatography-tandem mass spectrometry (LC-MS/MS) is becoming more frequently used in the analysis of OTC owing to its high sensitivity and ability. Electrospray ionization (ESI) [55-57] and atmospheric pressure chemical ionization (APCI) [41] methods combined with tandem mass spectrometry are favored because of their higher sensitivity and better reproducibility. Hamscher et al. [58] developed a method for the determination of persistent TC residues in soil fertilized with manure by HPLC tandem mass spectrometry, MS-MS, and confirmation by MS-MS-MS. Zhu et al. [59] developed an LC-tandem mass spectrometry for the analysis of common tetracyclines in water. The detection limit for oxytetracycline was 0.21 pg/L. Lykkeberg et al. [60] used LC-MS/MS for determination of oxytetracycline and its impurities EOTC, TC, ETC, ADOTC, oc-AOTC, and /i-AOTC. 

G. A. van der Doelen, K. J. van den Berg, J. J. Boon, N. Shibayama, E. R. de la Rie, W. J. L. Genuit, Analysis of fresh triterpenoid resins and aged triterpenoid varnishes by high performance liquid chromatography atmospheric pressure chemical ionization (tandem) mass spectrometry, J. Chromatogr., A, 809, 21 37 (1998). 

Substituted tetrazoles reacting in the mass spectrometer with acyl ions afforded 2,5-disubstituted 1,3,4-oxadiazoles with nitrogen loss. Tandem mass spectrometry allowed for the collision-induced dissociation of the products. Chemical ionization was the better method to make the transformation. A scheme for the transformation of 5-substituted tetrazoles into 2,5-disubstituted 1,3,4-oxadiazoles was proposed (Scheme 1) <2001JMP1069>. The fragmentation patterns of monocyclic l,3,4-oxadiazolium-2-thiolates have been proposed by Ollis and Ramsden <1974J(P1)645>. 

Chu, I. et al. 2000. Validation of higher throughput high-performance liquid chromatography/atmo-spheric pressure chemical ionization tandem mass spectrometry assays to conduct cytochrome P450s... 

Beaudry F. et al., 1998. In vivo pharmacokinetic screening in cassette dosing experiments Use of online Pros-pekt liquid chromatography/atmospheric pressure chemical ionization tandem mass spectrometry technology in drug discovery. Rapid Commun Mass Spectrom 12 1216. 

Bourgogne E., Grivet C., and Hopfgartner G., 2005. Determination of talinolol in human plasma using automated online solid phase extraction combined with atmospheric pressure chemical ionization tandem mass spectrometry. J Chromatogr B 820 103. 

Stereochemical aspects in mass spectrometry have aroused more and more interest. El mass spectra of stereoisomers are practically indistinguishable. However, the use of soft ionization methods (chemical ionization, field ionization, etc.) accompanied by tandem mass spectrometry allows important and reliable conclusions on the molecular structures to be drawn. 

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