Determination of naphthalenesulfonic acid isomers by large-volume on-line derivatization and gas chromatography-mass spectrometry

This work presents a modified method to analyze polar and water-soluble nap hthalene monosulfonic acid (NS) isomers in industrial effluents and river w ater samples. The method involves extraction of samples by a styrene-diviny lbenzene copolymer solid-phase extraction cartridge, and on-line derivatiza tion in the GC injection port using a large-volume (10 mul) sample injectio n with tetrabutylammonium salts. The analytes were then identified and quan titatively determined by GC-MS. The large-volume injection-port derivatizat ion technique provides sensitivity, fast and reproducible results for NS is omers, to quantitation at 0.05 mug/l in 200 ml of water sample. Enhanced ex tracted mass chromatograms of molecular ion and [M - 56](+) ion of butylate d NS isomers by electron impact ionization MS allows us to determine residu es at trace levels in environmental samples. Recoveries of the NS isomers i n spiked water samples ranged from 70 to 82% with RSDs around 10%. Naphthal ene-2-sulfonic acid was found as a major pollutant and propagated in surfac e water and industrial effluents. (C) 2001 Elsevier Science B.V. All rights reserved.