National Risk Management Research Laboratory/Water Supply and Water Resources Division, US Environmental Protection Agency, 26 West Martin Luther King Drive, Cincinnati, OH 45268, USA.
J Chromatogr A. 2010 Jan 29;1217(5):676-82. doi: 10.1016/j.chroma.2009.12.012. Epub 2009 Dec 5.
Although the herbicide atrazine has been reported to not react measurably with free chlorine during drinking water treatment, this work demonstrates that at contact times consistent with drinking water distribution system residence times, a transformation of atrazine can be observed. Some transformation products detected through the use of high performance liquid chromatography-electrospray mass spectrometry are consistent with the formation of N-chloro atrazine. The effects of applied chlorine, pH, and reaction time on the transformation reaction were studied to help understand the practical implications of the transformation on the accurate determination of atrazine in drinking waters. The errors in the determination of atrazine are a function of the type of dechlorinating agent applied during sample preparation and the analytical instrumentation utilized. When a reductive dechlorinating agent, such as sodium sulfite or ascorbic acid is used, the quantification of the atrazine can be inaccurate, ranging from 2-fold at pH 7.5 to 30-fold at pH 6.0. The results suggest HPLC/UV and ammonium chloride quenching may be best for accurate quantification. Hence, the results also appear to have implications for both compliance monitoring and health effects studies that utilize gas chromatography analysis with sodium sulfite or ascorbic acid as the quenching agent.
虽然已有报道称，在饮用水处理过程中，除草剂莠去津与游离氯不会发生明显反应，但本研究表明，在与饮用水分配系统停留时间一致的接触时间内，莠去津会发生转化。通过使用高效液相色谱-电喷雾质谱检测到的一些转化产物与 N-氯莠去津的形成一致。本研究考察了投氯量、pH 值和反应时间对转化反应的影响，以帮助了解转化对准确测定饮用水中莠去津的实际意义。在测定莠去津的过程中产生的误差取决于样品制备过程中应用的脱氯剂的类型和分析仪器的使用。当使用还原性脱氯剂（如亚硫酸钠或抗坏血酸）时，莠去津的定量可能不准确，在 pH 值为 7.5 时误差约为 2 倍，在 pH 值为 6.0 时误差约为 30 倍。研究结果表明，高效液相色谱/紫外检测法和氯化铵淬灭法可能最适合准确定量。因此，这些结果似乎也对使用亚硫酸钠或抗坏血酸作为淬灭剂的气相色谱分析进行合规监测和健康影响研究具有重要意义。
