Improved method for the determination of zinc pyrithione in environmental water samples incorporating on-line extraction and preconcentration coupled with liquid chromatography atmospheric pressure chemical ionisation mass spectrometry

A method has been developed for the determination of zinc pyrithione (ZnPT) in environmental water samples using monolithic reversed-phase silica columns for rapid on-line large volume solid phase extraction in tandem with on-line matrix removal using sacrificial strong anion exchange (SAX) columns. This is coupled with reversed-phase liquid chromatography with atmospheric pressure chemical ionisation mass spectrometric detection. Limits of detection in spiked river water samples, using a 200 mL preconcentration volume, were determined as 18 ng L−1, with a limit of quantitation of 62 ng L−1. The percentage recovery from spiked river water was found to be 72 ± 9 (n = 3 extractions), whilst overall method precision, following 10 repeat complete analyses was found to be 27% RSD at 1 μg L−1. Linearity was determined over the concentration range of 0.25–10 μg L−1 and the calculated regression coefficient was R2 = 0.9802. The method was used to investigate the environmental fate of zinc pyrithione in waters and its partition coefficient between sediment and water phases.