On-line solid-phase extraction thermal desorption gas chromatography with ion trap detection tandem mass spectrometry for the analysis of microcontaminants in water

An improved set-up for solid-phase extraction with thermal desorption coupled on-line to gas chromatography (SPETD-GC) is presented, It includes a newly designed liner for a programmable temperature vaporizer BTV) and an improved water elimination system, The SPETD procedure now includes a washing step with HPLC-grade water to prevent degradation of analytes due to interaction with remaining sample constituents, The system was used to analyze surface and tap water samples over a ii-month period, No decrease of chromatographic or trace-enrichment performance was observed, and a liner packed with Tenax GR could be used for at least 150 analyses, The SPETD module was coupled to GC,vith ion-trap detection for mass spectrometric (MS) and MS/MS detection, The linearity and repeatability of the procedure for several pesticides which were tested in the 0.5-10 mu g/1 range were fully satisfactory (1 mu g/l, RSD range 5-11%; n = 5), When using sample volumes of 0.1 ml only, detection limits were as low as 0.1-0.2 mu g/l. As an example, the confirmation and quantification of a suspected pesticide in a real-life sample using electron impact and positive chemical ionization in both the MS and MS/MS mode is shown.