Monitoring of antifouling agents in water samples by on-line solid-phase extraction-liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

An automatic method for determining diuron, irgarol 1051, folpet and dichlo fluanid in seawater samples have been developed. This method is based on th e on-line coupling of solid-phase extraction (SPE) with a highly crosslinke d polymeric sorbent, LiChrolut EN, to liquid chromatography followed by atm ospheric pressure chemical ionization (APCI) and mass spectrometry. The ope rational parameters affecting the APCI interface have been studied in both positive and negative ionization modes. The use of LiChrolut EN in the SPE produced recoveries of over 85% for all the compounds when 100 mi of seawat er sample was preconcentrated. Calibration was carried out in both ionizati on modes and in full-scan and selected-ion monitoring (SIM). The method all owed all the analytes to be detected at 5 ng 1(-1) in SIM acquisition mode except folpet, which, because of its low response, could only be detected a t 250 ng 1(-1). The method was used to analyse water samples taken from fiv e different marina and fishing ports along the coast of Tarragona, Cataloni a (Spain), over a 5-month period. Diuron and irgarol 1051 were detected and quantified in most samples at concentration levels ranging from 27 to 420 ng 1(-1) for diuron and from 15 to 511 ng 1(-1) for irgarol 1051. (C) 2001 Elsevier Science B.V. All rights reserved.