Determination of 1,2,4- And 1,3,5-Trichlorobenzenes in Water Samples by Solid-Phase Extraction and Gas-Chromatography Coupled to Electron Capture

Gas chromatography of 1,2,4-trichlorobenzene and 1,3,5-trichlorobenzenes in water samples has been performed after adsorption from 80-mL sample on to a cartridge containing 200 mg cyanopropyl-bonded porous silica. The two trichlorobenzenes are desorbed with 500 μL carbon disulfide or pentane, which is concentrated and analysed by gas chromatography with electron-capture detection (GC-ECD). The recovery of 1–15 ppb trichlorobenzenes from distilled water and from Aniene and Tiber river water samples is ≥ 90% (standard deviation ≤ 5.5). The limit of detection is 0.02 ng mL−1 and 0.03 ng mL−1 for 1,2,4-trichlorobenzene and 1,3,5-trichlorobenzene (standard deviation ≤ 9), respectively. The method described is fast, simple and reproducible.