ANALYSIS OF ORGANIC POLLUTANTS IN WATER AT TRACE LEVELS USING FULLY AUTOMATED SOLID-PHASE EXTRACTION COUPLED TO HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

A method has been developed for the determination of trace levels of 3 2 pesticides, 19 explosives and 16 polycyclic aromatic hydrocarbons (P AH) in water in three individual steps. Solid-phase enrichment (SPE) i s coupled to high-performance liquid chromatography (HPLC) with a full y automated system. The organic pollutants are enriched on reusable ca rtridges packed with adsorbent materials: pesticides and explosives on a mixed bed of divinylbenzene-ethylvinylbenzene copolymers (LiChrolut EN(R)) and perfluorinated polyethylene (PolyF(R)), and polycyclic aro matic hydrocarbons on C-18-modified silica (Zorbax(R) ODS1). Thermally assisted desorption (TAD) has been shown to increase the recovery of analytes significantly. As all enriched analytes are transferred to th e detector, only fifty millilitres of sample is needed for each single on-line analysis, compared with at least a litre for conventional met hods. The separation of the enriched organic analytes is performed on specialized HPLC columns based on reversed-phase materials. The limits of detection of the system employed were found to be below 100 ng L-1 . Use of fluorescence detection for the polycyclic aromatic hydrocarbo ns resulted in limits of detection in the upper pg L-1 range. The k va lues, number of theoretical plates, the recovery rates and the limits of detection of this method for fast screening of organic pollutants f rom three fifty-millilitre aqueous samples are described.