Zhao Ru-Song, Lao Wen-Jian, Xu Xiao-Bai
Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, PR China.
Talanta. 2004 Mar 10;62(4):751-6. doi: 10.1016/j.talanta.2003.09.035.
In the present work, a novel method for the determination of trihalomethanes (THMs) such as chloroform, dichlorobromomethane, chlorodibromomethane and bromoform in drinking water has been described. It is based on coupling headspace liquid-phase microextraction (HS-LPME) with gas chromatography-electron capture detector (GC-ECD). A microdrop of organic solvent at the tip of a commercial microsyringe was used to extract analytes from aqueous samples. Three organic solvents-xylene, ethylene glycol and 1-octanol-were compared and 1-octanol was the most sensitive solvent for the analytes. Extraction conditions such as headspace volume, extraction time, stirring rate, content of NaCl and extraction temperature were found to have significant influence on extraction efficiency. The optimized conditions were 15ml headspace volume in a 40ml vial, 10min extraction time and 800rpm stirring rate at 20 degrees C with 0.3gml(-1) NaCl. The linear range was 1-100mugl(-1) for THMs. The limits of detection (LODs) ranged from 0.15mugl(-1) (for dichlorobromomethane and chlorodibromomethane) to 0.4mugl(-1) (for chloroform); and relative standard deviations (RSD) for most of THMs at the 10mugl(-1) level were below 10%. Real samples collected from tap water and well water were successfully analyzed using the proposed method. The recovery of spiked water samples was from 101 to 112%.
在本研究中，描述了一种测定饮用水中三卤甲烷（THMs）（如氯仿、二氯溴甲烷、氯二溴甲烷和溴仿）的新方法。该方法基于顶空液相微萃取（HS-LPME）与气相色谱-电子捕获检测器（GC-ECD）联用。使用商用微量注射器尖端的一滴有机溶剂从水样中萃取分析物。比较了三种有机溶剂——二甲苯、乙二醇和1-辛醇，发现1-辛醇对分析物最为灵敏。发现顶空体积、萃取时间、搅拌速率、NaCl含量和萃取温度等萃取条件对萃取效率有显著影响。优化条件为在40ml小瓶中顶空体积15ml、萃取时间10min、20℃下搅拌速率800rpm且NaCl含量为0.3gml(-1)。THMs的线性范围为1-100μg l(-1)。检测限（LODs）范围为0.15μg l(-1)（二氯溴甲烷和氯二溴甲烷）至0.4μg l(-1)（氯仿）；大多数THMs在10μg l(-1)水平时的相对标准偏差（RSD）低于10%。使用所提出的方法成功分析了从自来水和井水中采集的实际样品。加标水样的回收率为101%至112%。
