SELECTIVE AND SENSITIVE DETECTION OF ORGANIC CONTAMINANTS IN WATER SAMPLES BY ONLINE TRACE ENRICHMENT GAS-CHROMATOGRAPHY MASS-SPECTROMETRY

Liquid chromatographic (LC) type trace enrichment is coupled on-line w ith capillary gas chromatography (GC) with mass spectrometric (MS) det ection for the analysis of aqueous samples. A volume of 1-10 ml of an aqueous sample is preconcentrated on a trace-enrichment column packed with a polymeric stationary phase. After cleanup with HPLC-grade water the precolumn is dried with nitrogen and subsequently desorbed with e thyl acetate. A fraction of 60 mul is introduced on-line into a diphen yltetramethyldisilazane-deactivated retention gap under partially conc urrent solvent evaporation conditions and using an early solvent vapor exit. The analytes are separated and detected by means of GC-MS. The potential of the LC-GC-MS system for monitoring organic pollutants in river and drinking water is studied. Target analysis is carried out wi th atrazine and simazine as model compounds; the detection limits achi eved under full-scan and multiple ion detection conditions are 30 pg a nd 5 pg, respectively. Identification of unknown compounds (non-target analysis), is demonstrated using a river water sample spiked with 168 pollutants varying in polarity and volatility.