Chen Xin, Wei Xiao, Zhou Ying, Zheng Weiwei, Chen Yuehuo, Zhang Dong, Wu Yuxin, Jiang Songhui, Qu Weidong
Key Laboratory of Public Health and Safety, Ministry of Education, Department of Environment Health, School of Public Health, Fudan University, Shanghai 20032, China.
Wei Sheng Yan Jiu. 2010 Mar;39(2):187-90.
The purpose of this study is to investigate the changes of concentration of trihalomethanes (THMs: chloroform, bromodichloromethane, chlorodibromomethane, bromoform) and haloacetic acids (HAAs: monochloroacetic acid, monobromoacetic acid, dichloroacetic acid, dibromoacetic acid, trichloroacetic acid, bromochloroacetic acid) in water samples with holding time and their stability in extract.
Two water samples from pipe network were collected and added 10 microg/L of THMs mixed standards and 10 microg/L of HAAs mixed standards respectively. The concentrations of THMs and HAAs were measured by U.S. EPA methods 551.1 and 552.3 on the day after sampling, 3 days, 7 days and 14 days, and compared the changes with holding time. The extract with THMs or HAAs mixed standards in the preserving of the day, 7 days, 14 days, 21 days and 30 days were measured by the concentration of THMs and HAAs, compared the changes of targets concentration with holding time.
Impact of sample holding time is an important factor in the concentration of the targets which significantly decreased with the extension of the time. The concentration of targets in extract except drichloroactic acid, keep stable in the periods of measurement.
Sample holding times have a greater impact on the determination of THMs and HAAs, therefore, we suggest that samples be measured or finished pretreatment on the day when sample was collected. In addition to drichloroacetic acid, the concentration of other targets in the extract can be stable for more than 30 days.
本研究旨在调查水样中三卤甲烷（THMs：氯仿、溴二氯甲烷、二溴一氯甲烷、溴仿）和卤乙酸（HAAs：一氯乙酸、一溴乙酸、二氯乙酸、二溴乙酸、三氯乙酸、溴氯乙酸）浓度随保存时间的变化及其在提取物中的稳定性。
采集两份管网水样，分别加入10μg/L的THMs混合标准品和10μg/L的HAAs混合标准品。在采样后第1天、3天、7天和14天，采用美国环保署方法551.1和552.3测定THMs和HAAs的浓度，并比较其随保存时间的变化。对保存1天、7天、14天、21天和30天的含有THMs或HAAs混合标准品的提取物，测定THMs和HAAs的浓度，比较目标物浓度随保存时间的变化。
样品保存时间是影响目标物浓度的重要因素，目标物浓度随时间延长显著降低。除二氯乙酸外，提取物中目标物的浓度在测定期间保持稳定。
样品保存时间对THMs和HAAs的测定有较大影响，因此建议在样品采集当天进行测定或完成预处理。除二氯乙酸外，提取物中其他目标物的浓度可稳定30天以上。
