GC Determination of 7 Benzene Homologues in Water with Separation by Dispersive Liquid-liquid Microextraction

The method was proposed for determination of 7 benzene homologues in water by dispersive liquid-liquid microextraction-GC. The water sample (10.00 mL) was extracted for 30 s with 100 μL of CS₂, and with 0.5 mL of CH₃OH added as dispersant. Seven benzene homologues were transferred from water into CS₂, and enriched to about 100 times in concentration. After centrifuging, the lower phase of CS₂ was taken and analyzed by GC. Large diameter capillary column and sampling by the mode of non-streaming together with FID detector were adopted in GC analysis. Linear relationships between values of peak areas and mass concentrations of 7 the benzene homoloques were obtained in the same range of 0.002 0-1.00 mg·L^-1, and values of detection limits (3S/N) found were in the range of 0.5-0.6 μg·L^-1. Tests for recovery were made by standard addition method at 3 concentration levels, giving values of recovery in the range of 87.0%-101% and RSDs (n=6) less than 8.5%.