Determination of the antifouling agent zinc pyrithione in water samples bycopper chelate formation and high-performance liquid chromatography atmospheric pressure chemical ionisation mass spectrometry

Zinc pyrithione has recently been incorporated into antifouling paints as a booster biocide, which is slowly released into the water as the paint ages . In order to determine concentrations of zinc pyrithione (ZPT) in aqueous samples, a liquid chromatographic method has been developed. Since ZPT inte racts with certain reversed-phase packing materials or stainless steel comp onents of the HPLC system, the method uses transchelation of the ZPT into t he stable copper(II) complex before analysis by liquid chromatography coupl ed to atmospheric pressure chemical ionisation mass spectrometry. ZPT was e xtracted as copper pyrithione using dichloromethane with adequate recovery (77% +/- 17%, n = 6) from 2-1 water samples. The limit of detection was cal culated to be 20 ng/l, using selected ion monitoring. The analysis of sampl es collected from various UK marinas showed no detectable concentrations to be present, whilst a laboratory-based study confirmed that this is probabl y due to the rapid photodegradation of ZPT in seawater. Crown copyright (C) 1999 Published by Elsevier Science B.V. All rights reserved.