Determination of two isomers of tetrachloroethane in urine by liquid-liquid extraction-gas chromatography / 中国职业医学

ABSTRACT

ObjectiveTo establish a method for the determination of 1,1,1,2-tetrachloroethane (TeCA) and 1,1,2,2-TeCA in human urine using liquid-liquid extraction-gas chromatography. Methods The 5.0 mL urine sample was mixed with 2.0 g anhydrous sodium sulfate and 5.0 mL ethyl acetate, then vortexed mixing. The 1.0 mL extraction was separated by 100% dimethylpolysiloxane capillary gas chromatography column, detected by flame ionization detector, and quantified by an external standard method. Results The linear ranges of 1,1,1,2-TeCA and 1,1,2,2-TeCA were 0.250-50.750 mg/L, with both correlation coefficients of >0.999 9. The detection limit of 1,1,1,2-TeCA in urine was 0.020 mg/L, and the lower limit of quantification was 0.060 mg/L. The average recovery was 88.02%-101.32%, and the within-run and between-run relative standard deviations (RSDs) were 0.11%-0.47% and 0.39%-1.09%, respectively. The detection limit of 1,1,2,2-TeCA in urine was 0.050 mg/L, and the lower limit of quantification was 0.150 mg/L. The average recovery was 93.42%-101.32%, and the within-run and between-run RSDs were 0.28%-1.04% and 0.50%-1.03%, respectively. Both the 1,1,1,2-TeCA and 1,1,2,2-TeCA cannot be stored at room temperature. The 1,1,2,2-TeCA can be stored at 4 ℃ for at least three days. At -20 ℃, the 1,1,1,2-TeCA can only be stored for one day, while 1,1,2,2-TeCA can be stored for at least five days. Conclusion This method has high sensitivity, good specificity, simple sample pretreatment, and more intuitive and reliable results. It can be used to determine the level of 1,1,1,2-TeCA and 1,1,2,2-TeCA in urine of occupational population.