顶空固相微萃取/气相色谱/质谱法测定水中三氯乙醛

Determination of Trichloroacetaldehyde in Water by Headspace Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry

将顶空固相微萃取与气相色谱/质谱仪联用,通过测定三氯乙醛在碱性条件下水解产物三氯甲烷,建立了一种测定地表水和生活饮用水中三氯乙醛化合物的新方法。研究了不同材质萃取头、加碱量、萃取温度和萃取时间等对萃取效率的影响,结果表明,该方法线性范围为0.1~10μg/L,相关系数(r)为0.999 4,检出限达到0.01μg/L。选取5.0μg/L和0.2μg/L两个浓度进行纯水加标实验,平均回收率分别为99.5%、96.7%,相对标准偏差分别为2.2%、7.4%。分别对饮用水和地表水水样进行了加标回收率实验,其平均回收率范围在92.5%~99.4%之间,相对标准偏差为2.1%~9.4%。该方法具有预处理时间短、灵敏度高、精密度和准确度好等特点,满足实际水样的检测要求。与国标GB/T 5750.10—2006中的气相色谱法相比,预处理时间由2.5 h缩短至0.5 h,分析效率显著提高,同时,灵敏度也比国标方法提高了100倍。

A new method of headspace solid-phase microextraction combined with gas chromatography/mass spectrometry was developed to determine the level of trichloroacetaldehyde in surface water and drinking water by measuring the concentration of trichloromethane, which is a hydrolyzed product of trichloroacetaldehyde under alkaline conditions. The effects of different extraction heads,dosages of alkali addition,extraction temperature and extraction time on the extraction efficiency were studied. The results indicated that the proposed method achieved the measurement of trichloroacetaldehyde over the range of 0. 1-10 μg/L with a correlation coefficient of 0. 999 4,and detection limit was 0. 01 μg/L. The average recovery of 5. 0 μg/L and 0. 2 μg/L trichloromethane in pure water were 99. 5% and 96. 7%,respectively,and the RSDs were 2. 2% and 7. 4%,respectively.The average recovery of drinking water and surface water was 92. 5%-99. 4%,and the RSDs was2. 1%-9. 4%. This method showed the characteristics of short pretreatment time,high sensitivity,precision and accuracy,which could meet the requirements of actual water quality detection. Compared with the gas chromatography method from GB 5750. 10-2006,the pretreatment time is reduced from 2. 5 h to 0. 5 h,and the analysis efficiency is significantly improved. Meanwhile,the sensitivity is also 100 times higher than that of the national standard method.