挥发性卤代烃地表水环境样品保存方法研究

摘要

This paper studies the various factors on the impact of water sample storage of volatile halohydrocarbons,because the domestic and international specifications have different content about it.The results show that,it could reduce the loss rate of volatile halohydroearbons of water sample about 2％ to 25％ by adding hydrochloric acid to adjust pH ≤ 2,and reduce the loss rate about 10％ by adding ascorbic acid or sodium thiosulfate.The best method for preserving volatile halohydrocarbons samples is that,adding hydrochloric acid to adjust pH2,adding ascorbic acid or sodium thiosulfate in order to get rid of chlorine,refrigeration and completing the analysis in the 14 days.In usually work,the water sample could be not adjusted pH≤2 and not added ascorbic acid or sodium thiosulfate,if we can complete the analysis in the 2 days and the water samples do not contain chlorine.%针对国内外监测技术规范对挥发性卤代烃样品保存条件不一致的问题,开展不同因素对挥发性卤代烃样品保存的影响研究.结果表明,调节pH≤2可使水样中挥发性卤代烃的损失率减少2％ ～25％；在水样中加入抗坏血酸或硫代硫酸钠可减少目标物的损失率约10％.挥发性卤代烃样品的最佳保存条件:加盐酸调节水样pH≤2,加10％硫代硫酸钠或抗坏血酸除余氯(有余氯时),冷藏,14 d内完成测试.在实际工作中,对未受余氯影响的集中式饮用水源地水样,特别是水库水样,若能在2d内完成测试,在冷藏保存的条件下,可以考虑不调节pH,不添加固定剂.