Multiresidue method for the analysis of five antifouling agents in marine and coastal waters by gas chromatography–mass spectrometry with large-volume injection

A simple multiresidue method has been developed for the determination of five pesticides, commonly used as active ingredients in antifouling paints, in seawater samples. The pesticides studied were: chlorothalonil (2,4,5,6-tetrachloro-isophthalonitrile), dichlofluanid (N-dimethyl-N-phenylsulphamide), Sea-Nine 211 (4,5-dichloro-2-n-octyl-4-isothazolin-3-one), Irgarol 1051 (2-methylthio-4-tert.-butylamino-6-cyclopropylamino-s-triazine) and TCMTB (2-thiocyanomethylthiobenzothiazole). The analytes were extracted from 200 ml water samples, using solid-phase extraction. A copolymer with hydrophilic–lipophilic balance was used as sorbent yielding good recoveries (82–95%) for most compounds except dichlofluanid and Sea-Nine 211 (<60%). Large volume injection (10 μl) gas chromatography and electron impact ionization MS (selected ion monitoring mode) detection enabled these compounds to be identified and quantified at the 1.2–3.0 ng/l level. Analysis of samples performed in three marinas in Almerı́a (Spain) revealed the presence of Irgarol 1051 in all the cases, at concentration levels between 25 and 450 ng/l.