Method development for trace determination of poly(naphthalenesulfonate)-type pollutants in water by liquid chromatography-electrospray mass spectrometry

A very sensitive analytical procedure based on LC-MS for determining trace amounts of the more relevant poly(naphthalenesulfonate) (PNS) contaminants present in environmental waters is presented. Extraction was performed on a styrene-divinylbenzene copolymer resin solid-phase extraction cartridge af ter addition of ammonium acetate to the sample. Small amounts of ammonium a cetate in the mobile phase allowed the determination and characterisation o f the four shorter oligomers by liquid chromatography-electrospray mass spe ctrometry, Under such conditions the electrospray process generates fully i onised molecules which greatly simplifies interpretation of spectra and qua ntitation. Additionally, confirmatory ions can be generated by the in-sourc e collision-induced decomposition process. The effectiveness of the method was assessed in recovery experiments from drinking and river water samples spiked with commercial mixtures of PNS concrete plasticizers also referred as naphthalenesulfonate-formaldehyde condensates. Moreover, the performance of this method was compared to methods using ion-pair chromatography coupl ed with fluorimetric and mass spectrometric detection. Method detection lim its were in the low picomolar range (1 ng/l for the monomer) for each isome r. In order to evaluate the environmental relevance of PNS type compounds w aste, river and ground water grab samples were analysed. Concentrations of PNS oligomers detected in these samples ranged between 53 ng/l and 32 mug/l . (C) 2001 Elsevier Science B.V. All rights reserved.