衍生化气相色谱法同时测定尿中三氯乙烯的3种氯代乙酸代谢产物

Simultaneous Determination of Three Halogenated Acetic Acids in Urine by Derivatization Gas Chromatography

建立了以三氯化铁为催化剂,乙醇与尿中三氯乙烯的3种代谢产物(一氯乙酸、二氯乙酸、三氯乙酸)乙酯衍生化的气相色谱测定方法。对乙酯衍生化温度、时间、三氯化铁用量、乙醇用量进行探讨,确定了最优化的衍生条件为4 mL尿样加入1.05 mmol三氯化铁、2 mL乙醇,90℃水浴50 min,经2 mL正己烷萃取后直接进样测定。尿中一氯乙酸、二氯乙酸、三氯乙酸的浓度分别在40～2 400、20～1 000、10～500μg/L范围内呈良好线性,相关系数分别为0.999 8、0.999 3和0.999 2,3种氯代乙酸在尿样中的平均加标回收率为104%、109%和106%。方法的检出限分别为4.67、1.32、0.27μg/L。该方法乙酯衍生化试剂低毒、低腐蚀性,反应条件温和,操作简便,已成功用于三氯乙烯职业暴露人群尿样中3种代谢产物的生物检测。

A sensitive and reliable method was developed for the quantitative determination of three metabolites of trichloroethylene, e.g. monochloroacetic acid （MCA） , diehloroacetic acid （DCA） and trichloroacetic acid（TCA） , in urine sample. Three metabolites were derivatized by ethanol es- terification in the presence of ferric chloride acted. Effects of esterification temperature, esterification time and amounts of ferric chloride and ethanol were discussed, and the optimization conditions were using 4 mL urine sample mixed with 1.05 mmol ferric chloride and 2.0 mL ethanol to derivatize for 50 min in 90 ℃ water bath. The three ethyl esters in sample were simultaneously determined by derivatization gas chromatography coupled with electron-capture detection after extracted with 2 mL hexane. The method showed good linearities in the ranges of 40 - 2 400, 20 - 1 000 μg/L and 10 - 500 μg/ L for monochloroacetic acid, dichloroacetic acid and trichloroacetic acid, with correlation coefficients of 0. 999 8, 0. 999 3 and 0. 999 2, respectively. The average spiked recoveries of three metabolites in urine sample were 104% , 109% and 106% , with their detection limits（S/N =3） of 4.67, 1.32 and 0. 27 μg/L, respectively. With the advantages of simplicity, requirements for relatively moderate reaction condition and non-corrosion reagents, the method was applied in the quantitative analysis of three metabolites in the urine samples from workers exposed to the trichloroethylene contaminant with satisfactory results.