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Fast atom bombardment (FAB) In conjunction with mass spectrometry/mass spectrometry (MS/MS) was applied to the analysis of anionic sufactants for the first time. Pure materials and commercial products were Investigated. Molecular weight distributions of commercial surfactants could be obtained from either the positive or negative FAB spectra. Colllslonally activated dissociation (CAD) spectra of selected Ions were used to confirm strutural Identification. Classes successfully characterized Include alkyl and alkylaryl sulfates and sulfonates, alcohol ether sulfates, -olefln sulfonates, fatty acid salts, sulfosucclnate dlesters, and N-acylated amino acids. The FAB MS/MS technique permits the rapid analysis of these Ionic surfactants without any derlvatlzatlon or preseparation.Two developments in the past few years which have significantly advanced the capabilities of mass spectrometry for chemical analysis are tandem mass spectrometry (MS/MS) and fast atom bombardment (FAB). Although the multisector instruments used in MS/MS have existed for many years, their capability for unaided separation (MS-I) and identification of single components (MS-II) in complex mixtures has only recently been explored. Analysis by MS/MS required that little sample pretreatment or preparation be done. MS/MS also provides a level of sensitivity and specificity not afforded by other instruments. The reader is referred to many fine articles which have been published on the theory and application of MS/MS (1-7).Fast atom bombardment has become recognized as the preferred method of ionization for ionic or multifunctional molecules (8-11). The use of FAB has grown tremendously over the last 2 years. A great many substances not amenable to ionization by conventional MS methods have now been analyzed sucessfully making use of FAB (12)(13)(14)(15). Anionic surfactants and surfactant mixtures are a class of such substances, and this paper is the first report of their analysis by FAB and FAB combined with MS/MS.

Supplementary Material Available: Figures giving variable-temperature) NMR spectra of la and their computer simulations and variable-temperature 13C('H| NMR spectra of an equilibrium mixture of the isomers lb and lc (2 pages). Ordering information is given on any current masthead page.

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Table IV. Selected Bond Angles (deg) for [n5-C5(CH3)5]W(S)2[CH2SiMe3] _ S(l)-W-S(2) 107.84 (8) S(l)-W-C(l) 101.1 (2) S(2)-W-C(l) 100.5(2) C(l)-Si-C(2) 113.4(4) C(l)-Si-C(3) 108.1 (4) C(l)-Si-C(4) 111.1(4) C(2)-S1-C(3) 108.7 (5) C(2)-Si-C(4) 108.1 (5) C(3)-Si-C(4) 107.2 (4) W-C(l)-Si 121.8(3) W-C(5)-C(10) 121.5(5) C(6)-C(5)-C( 9) 107.4 (5) C(6)-C(5)-C(10) 125.9 (6) C(9)-C(5)-C(10) 126.3 (6) W-C(6)-C(l 1) 123.3(5) C( 5)-C(6)-C( 7) 107.1 (5) C( 5)-C(6)-C(l 1) 125.6(6) C( 7)-C(6)-C(l 1) 127.3(6) W-C(7)-C(12) 125.3 (5) C(6)-C(7)-C(8) 108.4 (6) C(6)-C(7)-C(12) 124.8 (6) C(8)-C(7)-C(12) 126.7 (6) W-C(8)-C(13) 122.5 (5) C( 7)-C(8)-C( 9) 107.7 (6) C( 7)-C(8)-C(13) 124.9(7) C(9)-C(8)-C(13) 127.4(7) W-C(9)-C( 14) 123.7 (5) C(5)-C(9)-C(8) 109.3 (6) C(5)-C(9)-C( 14) 123.7 (6) C(8)-C(9)-C(14) 126.9(6) A ^-scan was used to estimate the maximum and minimum transmission coefficients. An empirical absorption correction (difabs40) was applied. Calculations were performed on a VAX-station 2000 computer using SDP-Plus software developed by Enraf-Nonius and B. A. Frenz & (39) Ibers,