地表水中微量三氟乙酸的分析方法

Determination of Trace Trifluoroacetic Acid in Surface Waterby Gas Chromatography-Mass Sepctrometry

研究了测定表面水体样品中微量三氟乙酸(TFA)浓度的分析方法,将样品中的三氟乙酸与硫酸二甲酯(DMS)在浓硫酸介质,温度80℃下衍生为三氟乙酸甲酯(MTFA),利用MTFA的易挥发性,50℃下顶空进样,并用气相色谱-质谱联用的方法检测样品中MTFA的浓度,进而得到环境水样中TFA的浓度.方法的检出限为3.0 μg/L.样品的加标回收率在84%～92%.应用此方法测定北京部分地表水样中的三氟乙酸浓度分别为43～107 ng/L.

A set of analytical method for determining trace trifluoroacetic acid ( TFA) in surface water is described, which includes the pre-treatment, preserving, concentrating and determining of the samples. The headspace auto sampler was elected to form the entire analytical instrument systems integrating with gas chromatography (GC) and mass spectrometry (MS). The TFA was changed into mehtyl-trifluoroacetate (MTFA) with dimethyl sulfate (DMS) at 80° C. Then the concentration of TFA in water samples was obtained by determining the concentration of MTFA with headspace sampling and GC-MS, using.the volatility of MTFA. The limit of detection of the analytical method was 3 μ g/L for TFA, the recovery of TFA ranged from 84% to 92%. The concentration of TFA in some surface water samples of Beijing were determined by applying the analytical method. The results indicate that the concentrations of TFA range from 43 to 107 ng/L in surface water in Beijing.