At-line SPE-GC-MS of micropollutants in water using the PrepStation

An automated at-line SPE-GC-MS system for the determination of micropolluta nts in aqueous samples, which is based on the PrepStation and uses large-vo lume on-column injections, has been redesigned. A cartridge made,from stain less steel and polychlorotrifluoroethylene and a 2-needle system was constr ucted which allow the determination of micropollutants at the low ng/L leve l without interferences from impurities extracted from the septa of the via ls or the commercial cartridges. No time-consuming pre-cleaning of the cart ridges or septa is required. The SPE sample extract (300 mu L) is transferr ed from the sample preparation module to the autosampler of the GC-MS and 5 0 or 100 mu L are injected. The analytical characteristics of the integrate d procedure such as analyte recovery (typically 80-105%) and repeatability (RSDs, 2-9%), were satisfactory. Several micropollutants were detected in ( unfiltered) river water at the 0.2-400 ng/L level using full-scan MS acquis ition. The system proved to be robust during the analysis of more than 100 tap and river water samples.