尽管氯因其有效性和低成本而成为美国使用的主要消毒剂，但当在氯化水中发现三卤甲烷（THM）时，出现了一个问题。因此，与具有电子捕获检测的气相色谱（GC）的昂贵过程相比，越来越需要一种相对廉价的THM监测方法。本文介绍了一种基于经典藤原反应的分光光度法测定成品水中三卤甲烷的方法，该方法采用溶剂萃取和化学定量。通过戊烷从溶液中提取THM，将提取物与50%NaOH和吡啶混合，然后缓慢加热，首先从溶液中去除溶剂，然后形成蓝粉色。该程序的特点是，当卤素化合物用氢氧化钠和吡啶加热时，会出现红色。颜色用可见分光光度计测量。 与带有电子捕获检测的气相色谱法相比，开发的比色法灵敏度和特异性较低。然而，该方法可以在未配备GC的水处理厂提供THM的半定量筛选。包括22个参考文献和表格。

Although chlorine has been the principal disinfectant used in the United States due to its effectiveness and low cost, a problem arose when trihalomethanes (THMs) were found in chlorinated waters. Subsequently, there is an increasing need for a relatively inexpensive method of monitoring THMs, in contrast to the costly process of gas chromatography (GC) with electron capture detection. This article describes research into a spectrophotometric procedure for determining THMs in finished waters that uses solvent extraction and chemical quantification and is based on the classic Fujiwara reaction. The THMs are extracted from solution by pentane, and the extract is mixed with 50% NaOH and pyridine and slowly heated first to strip the solvent from the solution and then to develop a bluish-pink color. The procedure is characterized by the red color that develops when a halogen compound is heated with sodium hydroxide and pyridine. Color is measured with a visible spectrophotometer. The developed colorimetric method, when compared with GC with electron capture detection, is less sensitive and less specific. However, this method can provide a semiquantitative screening of THMs at water treatment plants that are not equipped with a GC. Includes 22 references, tables.