Survivor-ion mass spectrometry is a method that relies on the selective monitoring of non-dissociating ions that underwent collisional neutralization acid reionization. These charge-permutation processes are found to modulate the relative intensities of precursor ions, both molecular ions and fragments, formed by electron impact from C6H10, C6H12, C6H12O, and xylene isomers. The relative intensities of highly-unsaturated ions, such as C5H5+, C4H2+., C3H3+, and C2H2+., and enol ions are enhanced in the survivor-ion spectra in dependence on the neutralization gas. Isomer differentiation through survivor-ion spectra is achieved for conjugated hexadienes, 1,4-hexadiene and cyclohexene, but not for hexenols and xylenes.

The gas-phase chemistry of phosphorus oxoacids, radicals, cations, and cation radicals is investigated by experiment and theory. Vertical neutralization of the stable P(OH)(4)(+) cation forms the P(OH)(4)(.) radical which dissociates exothermically within 4.5 mu s by loss of hydrogen to form phosphoric acid. Collisional reionization of vibrationally excited H3PO4 results in extensive dissociation by losses of hydroxyl groups. Vertical neutralization of the stable P(OK)(3)(.)t and HPO(OH)2(.+) ions forms stable molecules that are detected as survivor ions following reionization. Collisional activation of neutral trihydroxyphosphine, P(OH)(3), results in unimolecular isomerization to the more stable phosphorous acid, HPO(OH)(2). Ab initio calculations, carried out at the MP4(SDQ)/6-31+G(d)/MP2(FULL)/6-3+G(d) level of theory predict all the species under study to be stable equilibrium structures. The proton affinity of phosphoric acid is calculated as 807 kJ mol(-1). Vertical neutralization of P(OH)(4)(+) deposits 129 kJ mol(-1) in the radical formed making it kinetically unstable with respect to hydrogen loss that requires 90 kJ mol(-1). The most stable P(OH)(3) isomer (C-1) is 45 kJ mol(-1) less stable than HPO(OH)(2) but is separated by an isomerization barrier of 224 kJ mol(-1). The P(OH)(3)(.+) cation radical of C-3 symmetry is 136 kJ mol(-1) more stable than HPO(OH)(2)(.+). Vertical neutralization of P(OH)(3)(.+) forms a vibrationally excited neutral 103 kJ mol(-1) above the C-1 isomer, while neutralization of HPO(OK)(2)(.+) results in a 98 kJ mol(-1) excitation in the neutral phosphorous acid. The important role of Franck-Condon effects in the dissociations and isomerizations of gas-phase phosphorus oxoacids and radicals is discussed.

Survivor-ion mass spectrometry is used to distinguish stereoisomeric cis- and trans-4-methylcyclohexanol. The method involves producing ions by electron impact ionization and submitting them without mass selection to collisional neutralization and reionization, followed by selective monitoring of non-dissociating ions. The differences in the electron impact mass spectra of the stereoisomers, due to the different fragment ion elemental compositions and structures, are highlighted by collisional neutralization with Xe, NO and CH3SSCH3, followed by reionization with oxygen. The differences in the survivor-ion spectra are due to different neutralization efficiencies of the isobaric and isomeric ions produced by electron impact ionization, different stabilities of the intermediate neutral species, different reionization efficiencies and reionized ion stabilities. Neutralization-reionization spectra of the C7H12+., C6H9+ C3H6O+. and C3H5O+ ions from stereoisomeric 4-methylcyclohexanols are also reported.

Several multivariate methods are now available for the calibration of second-order or hyphenated instruments (e.g. GC/MS). When applied to bilinear data, it has been shown that calibration can be performed in the presence of unknown interferences - a significant advantage over first-order calibration. In this paper, non-bilinear rank annihilation (NBRA), a method which has the potential of handling, second-order non-bi-linear data, is studied through theoretical analysis and computer simulation. It is found that the second-order advantage can be carried over to non-bilinear data if a property defined as net analyte rank (NAR) holds for the analyte of interest. The net analyte signal (NAS) is defined accordingly for second-order calibration and the analogy to and difference from lower-order calibration are discussed. With NAS, some analytical figures of merit such as signal-to noise ratio, selectivity, sensitivity and limit of determination can be calculated for second order calibration. An application to MS/MS data is also given.

A new scan technique utilizing the tandem quadrupole acceleration-deceleration mass spectrometer is described. The technique is based on combined monitoring of neutral and ion precursors that fragment following collisional electron transfer to give rise to a selected low-mass neutral species and its ion, respectively. PO. is found to be a stable neutral species formed by dissociations of a variety of oxidized phosphorus compounds, such as di- and trialkyl phosphites, phosphates and phosphonic esters. These compounds can be selectively monitored through PO. precursor scans in multi-component mixtures. Interferences from isobaric neutral species, (ClC.)-C-35, (CH3S.), CH3 (SiH2.)-S-30, and their precursors are discussed. Neutralization-reionization spectra of phosphorus-containing radicals, PO., CH3OPH., CH3OPOH., .P(OCH3)2 and (CH3O)2PO., are also reported.

Organic Mass SpectrometryVolume 27, Issue 11 p. 1335-1336 Oms Letter Survivor ion mass spectrometry Frantisek Turecek, Corresponding Author Frantisek Turecek Department of Chemistry, BG-10, University of Washington, Seattle, Washington 98195, USADepartment of Chemistry, BG-10, University of Washington, Seattle, Washington 98195, USASearch for more papers by this authorMing Gu, Ming Gu Department of Chemistry, BG-10, University of Washington, Seattle, Washington 98195, USASearch for more papers by this author Frantisek Turecek, Corresponding Author Frantisek Turecek Department of Chemistry, BG-10, University of Washington, Seattle, Washington 98195, USADepartment of Chemistry, BG-10, University of Washington, Seattle, Washington 98195, USASearch for more papers by this authorMing Gu, Ming Gu Department of Chemistry, BG-10, University of Washington, Seattle, Washington 98195, USASearch for more papers by this author First published: November 1992 https://doi.org/10.1002/oms.1210271132Citations: 8AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. References 1 K. L. Busch, G. L. Glish, and S. A. McLuckey, Mass Spectrometry/Mass Spectrometry, VCH Publishers, New York (1988). 2(a) P. O. Danis, C. Wesdemiotis and F. W. McLafferty, J. Am. Chem. Soc., 105, 7454 (1983). (b) P. C. Burgers, J. L. Holmes, A. A. Mommers and J. K. Terlouw, Chem. Phys. Lett., 102, 1 (1983). 3 J. K. Terlouw, Adv. Mass Spectrom., 11, 984 (1989). 4 F. Turecek, M. Gu and S. L. Shaffer, J. Am. Soc. Mass Spectrom., 3, 493 (1992). 5(a) For a similar technique using charge-reversal spectra see T. Keough, J. H. Beynon and R. G. Cooks, Chem. Phys., 12, 191 (1976). (b) M. J. Polce, M. M. Cordero, C. Wesdemiotis and P. A. Bott, Int. J. Mass Spectrom. Ion Processes, 113, 35 (1992). 6 C. Wesdemiotis and R. Feng, Org. Mass Spectrom., 23, 416 (1988). 7 F. Turecek, D. E. Drinkwater and F. W. McLafferty, J. Am. Chem. Soc., 113, 5950 (1991). 8 S. G. Lias, J. E. Bartmess, J. F. Liebman, J. L. Holmes, R. D. Levin and W. G. Mallard, J. Phys. Chem. Ref. Data, 17, Supplement 1 (1988). 9 From the residuals, Rij = 2√∑[(ljm − l jm)/(im + lim + 1)]2, of ion intensities in the survivor ion mass spectra of iosmers i and j, 0 ≤ Rij ≤ √2. 10 P. Wolkoff, J. L. Holmes and F. P. Lossing, Can. J. Chem., 53, 251 (1980). Citing Literature Volume27, Issue11November 1992Pages 1335-1336 ReferencesRelatedInformation

A new tandem mass spectrometer of the quadrupole-acceleration lens-deceleration. lens-quadrupole (QADQ) configuration is described. The instrument is designed for neutralization-reionization studies and consists of a 2000-u quadrupole mass analyzer as MS-I, an acceleration electrostatic lens, a series of three differentially pumped collision cells, and an electrostatic deceleration lens, energy filter, and another 2000-u quadrupole mass analyzer as MS-II. The ion optical system achieves high total ion transmission for 5–9-keV ions. Unit mass resolution in neutralization-reionization mass spectra of aromatic compounds is demonstrated. Mass, kinetic energy, and linked scans at various levels of mass resolution and sensitivity are described.

The stability and dissociations of dimethylhydroxysulfuranyl radical, a key intermediate in the atmospheric oxidation of dimethyl sulfide, have been investigated by neutralization-reionization mass spectrometry and ab initio calculations. Dimethylhydroxysulfuranyl radical (1) and its d6 derivative 2 were generated in the gas phase by neutralization of protonated dimethylsulfoxide and dimethylsulfoxide-d6, respectively. Hypervalent radical 1 dissociates completely within 4.5-mu-s to CH3SOH by loss of CH3. and to (CH3)2S by loss of OH.. These primary products undergo further extensive dissociations. 2 also shows a minor dissociation to (CD3)2SO by loss of hydrogen atom in addition to the formation of CD3SOH and (CD3)2S by losses of CD3. and OH., respectively. Ab initio calculations (MP4/6-31 G*) find no potential energy minimum for 1 that collapses without barrier by oxygen-sulfur or carbon-sulfur bond fissions. Vertical neutralization of ion 1+ produces an unstable radical 1 lying 193 kJ mol-1 above the lowest energy (CH3)2S and OH. products. Relative energies of all primary dissociation products were calculated and compared with experimental data.