Headspace sorptive extraction using silicone tubes for the determination of chlorobenzenes in water

A new approach for headspace sorptive extraction is presented and demonstrated for the determination of 12 chlorobenzenes in water samples. It consists of a silicone tube (15-mm length) arranged around a stainless steel rod. This device is fixed on a septum cap and exposed to the headspace of 50 mL of a salt-saturated water sample. After extraction (60-min optimized extraction time), thermodesorption is carried out by direct insertion of the silicone tube into the thermodesorption-gas chromatography-mass spectrometry system. Desorption of the analytes is performed at 250 °C for 5 min with a gas flow of 50 mL/min. Repeatability (relative standard deviation 5–10%), extraction yields (9–46%), enrichment factors (129–657), and detection limits (0.002–0.012 μg/L) were determined and four real water samples were analyzed with the headspace tube extraction. The results were verified by standard addition. A comparison of headspace tube extraction with other headspace enrichment techniques underlined the high extraction capacity of the proposed method. A big advantage of tube extraction is the low cost of the silicone material. The tubes can be discarded after single use, avoiding carryover problems and cross-contamination. Figure Scheme of the HS-tube extraction and thermodesorption system