高效液相色谱法同时测定地表水中四种醛类化合物

甲醛、乙醛、丙烯醛和三氯乙醛均为环境中常见的醛类化合物,对人的皮肤和粘膜有刺激作用,且有致癌危险。在现行的国家标准《地表水环境质量标准》中,测定甲醛采用分光光度法,乙醛、丙烯醛和三氯乙醛则采用气相色谱法,方法复杂且不统一。本研究建立了2,4-二硝基苯肼(DNPH)衍生,高效液相色谱法同时测定地表水中甲醛、乙醛、丙烯醛和三氯乙醛的分析方法。考察溶液温度、酸度、反应时间对2,4-二硝基苯肼与水中醛类化合物反应的影响,探讨高效液相色谱三元梯度法分离后测定4种腙类化合物的条件。在温度为40℃、pH=3的条件下,水样与2,4-二硝基苯肼反应1 h后用二氯甲烷萃取,采用高效液相色谱三元梯度法分离后测定,4种化合物的回收率为73.1%～115%,相对标准偏差为0.71%～5.3%,检出限为3.50～28.6μg/L。本方法能够同时测定地表水中甲醛、乙醛、丙烯醛和三氯乙醛。

Determination of Aldehydes in Surface Water by High Performance Liquid Chromatography

Formaldehyde,acetaldehyde,acrolein and trichloroacetaldehyde have been a focus in the environment because of their toxicity and harmfulness as potential carcinogens.The four aldehydes were listed in the environmental quality standard for surface water in China and were monitored each month by the environmental monitoring department.According to the standard methods for determination of the four aldehydes,formaldehyde was determined by spectrophotometry and acetaldehyde,acrolein and trichloroacetaldehyde were detected by Gas Chromatography.A new analytical method has been developed for the determination of the four aldehydes by High Performance Liquid Chromatography(HPLC) after the 2,4-dinitrophenylhadrazine(DNPH) derivatization.The four aldehydes were separated by HPLC with a ternary gradient program,which mobile phase changed by linear gradient from pump A(Φwater=100%) 40%,B(Φmethanol=100%)50%,C(Φacetonitrile=100%) 10% to pump A(Φwater=100%) 20%,B(Φmethanol=100%) 60%,C(Φacetonitrile=100%) 20% in 15 min.Effect factors of acidity,temperature and reaction time on derivatization were studied,and the conditions for separation of four aldehydes were optimized.The water sample initially reacted with DNPH for one hour under the condition of pH=3 and 40℃,and then was extracted by dichloromethane.The recoveries of four compounds were in the range of 73.1%-115%,relative standard deviations were in the range of 0.71%-5.30%,and the detection limits were in the range of 3.50-28.6 μg/L.This method is simple,rapid and sensitive for the determination of the four aldehydes in surface water.