PILOT SURVEY FOR DETERMINATION OF THE ANTIFOULING AGENT IRGAROL-1051 IN ENCLOSED SEAWATER SAMPLES BY A DIRECT ENZYME-LINKED-IMMUNOSORBENT-ASSAY AND SOLID-PHASE EXTRACTION FOLLOWED BY LIQUID-CHROMATOGRAPHY DIODE-ARRAY DETECTION

The determination of Irgarol 1051 in enclosed seawaters from the Medit erranean Spanish Coast was accomplished by (ELISA). The results achiev ed with ELISA were compared with those obtained by an automated on-lin e solid-phase extraction (SPE) system (Prosneki) followed by liquid ch romatography-diode array detection (LC-DAD). LC-grade and seawater sam ples spiked with an unknown amount of Irgarol were analyzed with both techniques. Cross-reactivity experiments were carried out in order to assess the influence of other compounds present in the water samples i n the quantitation if Irgarol. Detection limits of 0.020 and 0.001 mu g/L were achieved after the analysis of seawater samples by ELISA and after preconcentration of 240 mL of seawater with SPE-LC-DAD, respecti vely. The monitoring survey using both techniques took place during 19 96-1997 with monthly sampling at the enclosed coastal Mediterranean ar ea with levels ranging from 0.007 to 0.325 mu g/L. In addition, diuron was also detected by LC-DAD in most of the samples with levels varyin g from 0.01 to 0.18 mu g/L. To avoid false positive determinations, th e confirmation of Irgarol and diuron was accomplished by liquid chroma tography-atmospheric pressure chemical ionization-mass spectrometry (L C-APCI-MS) detection.