On-line coupling of immunoaffinity-based solid-phase extraction and gas chromatography for the determination of s-triazines in aqueous samples

The potential of immunoaffinity-based solid-phase extraction (IASPE) couple d on-line to gas chromatography (GC) for the determination of micropollutan ts was studied with emphasis on the interfacing of the immunoaffinity-based SPE and GC parts of the system. The cartridge containing the immobilized a ntibodies was coupled to the gas chromatograph via a reversed-phase cartrid ge (copolymer sorbent). After trace enrichment of the analytes on the immun oaffinity cartridge, they were desorbed and recollected on the reversed-pha se cartridge by means of an acidic buffer. After clean-up and drying with n itrogen, desorption and transfer to the GC was done with ethyl acetate via an on-column interface in the partially concurrent solvent evaporation mode . The antibodies used in the immunoaffinity cartridge were raised against a trazine; several s-triazines were used as test compounds. Triazines that we re structurally similar to atrazine, showed quantitative recovery. As an ap plication, immunoaffinity SPE-GC was used for the analysis of river and was te water and orange juice. The selectivity of the system was such that non- selective flame ionization detection (FID) could be used to detect the anal ytes of interest in these complex matrices. The detection limits for 10-ml water samples were 15-25 ng/l for FID and about 1.5 ng/l for the nitrogen-p hosphorus detection. (C) 1999 Elsevier Science B.V. All rights reserved.