Selective and sensitive detection of organic contaminants in water samples by on-line trace enrichment-gas chromatography-mass spectrometry

Liquid chromatographic (LC) type trace enrichment is coupled online with capillary gas chromatography (GC) with mass spectrometric (MS) detection 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 ethyl acetate. A fraction of 60 μl is introduced on‐line into a diphenyltetramethyldisilazane‐deactivated retention gap under partially concurrent 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 with atrazine and simazine as model compounds; the detection limits achieved under full‐scan and multiple ion detection conditions are 30 pg and 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.