DIFFERENTIATION OF LINEAR AND BRANCHED ALKYLBENZENESULFONATES BY GAS-CHROMATOGRAPHY TANDEM MASS-SPECTROMETRY

A tandem mass spectrometric method was developed to differentiate line ar alkylbenzenesulfonates (LAS) and branched alkylbenezenesulfonates ( ABS) by gas chromatography and tandem mass spectrometry (GC/MS/MS). Ev en though the GC retention times of ABS are generally shorter than tho se of the corresponding LAS homologues, quantification is difficult be cause they still overlap to some extent. By monitoring the specific fr agmentation of derivatized LAS under negative chemical ionization cond itions that leads to a deprotonated vinyl-substituted benzenesulfinic acid and the fragmentation of ABS that yields a deprotonated 2-propeny l-substituted sulfinic acid, the overlapping segment can be broken dow n into LAS and ABS contributions. This allows the quantification of LA S and ABS mixtures such as occur, for instance, in the sedimentary rec ord of natural waters.