GC Determination of Benzene Homologues in Water Samples with Solid Phase Micro-extraction

GC with sample pretreatment by solid phase micro-extraction (SPME) was applied to the determination of 7 benzene homologues, i.e., benzene, methylbenzene, ethylbenzene, p-xylene, m-xylene, o-xylene and cumin, in water samples. To attain a higher efficiency for SPME, the 75 μm CAR/PDMS coating was applied to the micro-extractor, and the extraction was carried out at 20 ℃ for 40 min, with addition of 4 g NaCl to 10 mL of sample solution as salting out agent. The analyte were separated on DB-FFAP capillary column and detected by hydrogen FID. Linear relationships between values of peak area and mass concentration of the 7 benzene homologues were kept in the same range of 1.00-500 μg·L-1, with detection limits (3S/N) in the range of 0.12-0.19 μg·L-1. The proposed method was applied to the analysis of 4 environmental water samples, giving values of recovery found by standard addition method in the range of 93.3%-104.2%.