Analysis of linear alkylbenzenesulfonates in water samples by large-volumeinjection-port derivatization and gas chromatography-mass spectrometry

This work presents a modified method to analyze linear alkylbenzenesulfonat es (LASs) in water samples. The method involves extraction of samples by a graphitized carbon black (GCB) cartridge, and direct derivatization in the GC injection port using a large-volume (10-20 mu l) direct sample introduct ion (DSI) device with tetraalkylammonium (TAA) salts. The analytes were the n identified and quantitated by ion-trap GC-MS. The large-volume DSI inject ion-port derivatization technique provides sensitivity, fast and reproducib le results for LAS residues, to quantitation at 0.1 mu g/l in 200 mi of wat er samples. The retention effect of TAA salts in the injection port was not detected. Enhanced selected mass chromatograms of [M-55](+) ions of butyla ted C-10-C-13 LASs by electron impact ionization MS allows one to determine LAS residues at trace levels in environmental samples. Recovery of total L ASs in spiked variety water samples ranged from 89 to 112% while RSDs range d from 2 to 13%. (C) 1999 Elsevier Science B.V. All rights reserved.