Determination of traces of five antifouling agents in water by gas chromatography with positive/negative chemical ionisation and tandem mass spectrometric detection

A highly selective and sensitive gas chromatography–mass spectrometry methodology has been developed for the determination of five antifouling compounds, currently licensed for use in marine antifouling paints. The procedure uses an ion trap mass spectrometer provided with an external ion source that allows the combined use, in the same analysis, of positive (PCI) and negative (NCI) chemical ionisation and tandem mass spectrometric fragmentation (MS–MS). Ionisation and fragmentation processes were optimised individually for each compound, thus, permitting maximum sensitivity and selectivity to be obtained. A complete validation study, including those aspects that affect both correct quantification and unequivocal confirmation, demonstrated the good performance of the proposed method. Detection limits obtained were lower than 0.005 μg l−1, except for Irgarol 1051 (0.050 μg l−1). The method was applied to real seawater samples from different marinas to prove their use in routine analysis.