Development and application of immunoaffinity chromatography for the determination of the triazinic biocides in seawater

The development of an immunoaffinity chromatography (IAC) procedure for the selective extraction of the anti-fouling agent Irgarol 1051 [2-(tert.-butylamino)-4-(cyclopropylamino)-6-(methylthio)-1,3,5-triazine] from seawater is described. The anti-Irgarol 1051 antibodies were covalently bound to agarose-based beads support. IAC column capacities were higher than 400 ng and ethanol–water (70:30) was selected as eluting mixture. After percolation of 250 ml of water sample containing Irgarol 1051 at environmental levels (ng l−1), the breakthrough volume was still not achieved. Other triazine herbicides percolated through the IAC column showed good recoveries. Thus, this IAC procedure may be useful to extract related compounds. The developed IAC column was applied to real seawater samples and compared with RP-C18 cartridges. The limit of detection (LOD) reached by using the IAC procedure was twenty times lower than the LOD achieved by the RP-C18 cartridges using the same detection system. Irgarol 1051 was detected at ng l−1 levels in the Barcelona marina (northwestern Mediterranean Sea). An acceptable correlation between enzyme-linked immunosorbent assay and gas chromatography with nitrogen–phosphorus detection was observed, thus analysis of Irgarol 1051 can be performed by either one of the methods. In this work, further confirmation of the analyte identity for real samples was accomplished by gas chromatography–electron impact mass spectrometry.