Differentiation of Linear and Branched Alkylbenzenesulfonates by Gas Chromatography/Tandem Mass Spectrometry

Abstract

A tandem mass spectrometric method was developed to differentiate linear alkylbenzenesulfonates (LAS) and branched alkylbenezenesulfonates (ABS) by gas chromatography and tandem mass spectrometry (GC/MS/MS). Even though the GC retention times of ABS are generally shorter than those of the corresponding LAS homologues, quantification is difficult because they still overlap to some extent. By monitoring the specific fragmentation of derivatized LAS under negative chemical ionization conditions that leads to a deprotonated vinyl-substituted benzenesulfinic acid and the fragmentation of ABS that yields a deprotonated 2-propenyl-substituted sulfinic acid, the overlapping segment can be broken down into LAS and ABS contributions. This allows the quantification of LAS and ABS mixtures such as occur, for instance, in the sedimentary record of natural waters.