Eawag, Swiss Federal Institute of Aquatic Science and Technology, CH-8600 Dübendorf, Switzerland; Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland.
Institute of Biogeochemistry and Pollutant Dynamics, ETH Zürich, CH-8092 Zürich, Switzerland.
Water Res. 2014 Jul 1;58:258-68. doi: 10.1016/j.watres.2014.03.059. Epub 2014 Apr 4.
Trichloramine is a hazardous disinfection by-product, which is present in chlorinated swimming pools. Although it is primarily taken up by inhalation, the concentration in pool water is important to monitor pool water quality and to assess trichloramine mitigation strategies. To date, scarce data is available on trichloramine concentration in pool water due to the lack of a suitable and easily applicable analytical method. This study presents a novel low cost, colorimetric method which is easy to operate and suitable for on-site measurements of trichloramine concentrations ≥0.05 μM (≥0.01 mg L(-1) as Cl2). The analytical method (termed "extraction-based ABTS method") consists of, (i) trichloramine stripping from pool water samples, (ii) passing it through a solid phase filter, composed of silica gel impregnated with sulfamic acid to eliminate interferences and (iii) trichloramine reaction with the indicator 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) to produce the coloured ABTS(•-) radical, which is measured at λ = 405 nm to determine the trichloramine concentration in the pool water sample. A comparison of the extraction-based ABTS method with membrane introduction mass spectrometry (MIMS) for 28 pool samples revealed a good correlation of the two methods. The trichloramine concentration in pool samples is correlated to HOCl, which is the most important factor for its formation. Other parameters such as combined chlorine and pH play a minor role while no correlation between trichloramine and the urea or the TOC concentration was observed. On-site measurements with MIMS in a wading pool over 6 days with a time resolution of 1 h confirmed that trichloramine concentrations strongly responded to changes in free chlorine concentrations. A diurnal measurement of trichloramine with a time resolution of 20 min revealed that trichloramine concentrations reacted quickly and sensitively to the bather load and that urea is probably not the main precursor for its formation.
三氯胺是一种有害的消毒副产物，存在于氯化游泳池水中。尽管它主要通过吸入摄入，但池水中的浓度对于监测池水水质和评估三氯胺缓解策略很重要。迄今为止，由于缺乏合适且易于应用的分析方法，因此有关池水中三氯胺浓度的数据很少。本研究提出了一种新颖的低成本、比色法，该方法易于操作，适用于现场测量≥0.05μM（≥0.01mg/L 作为 Cl2）的三氯胺浓度。该分析方法（称为“基于提取的 ABTS 方法”）包括：（i）从游泳池水样中提取三氯胺，（ii）通过填充有氨基磺酸的硅胶的固相过滤器，以消除干扰，（iii）三氯胺与指示剂 2,2-偶氮-双（3-乙基苯并噻唑啉-6-磺酸）二铵盐（ABTS）反应生成有色 ABTS（•-）自由基，在 λ = 405nm 处测量以确定游泳池水样中的三氯胺浓度。28 个游泳池水样的基于提取的 ABTS 方法与膜导入质谱法（MIMS）的比较表明，两种方法具有良好的相关性。游泳池样品中的三氯胺浓度与 HOCl 相关，HOCl 是其形成的最重要因素。其他参数，如总余氯和 pH 值，作用较小，而三氯胺与尿素或 TOC 浓度之间没有相关性。6 天内每天在一个浅水池中用 MIMS 进行现场测量，时间分辨率为 1 小时，证实三氯胺浓度强烈响应自由氯浓度的变化。20 分钟时间分辨率的三氯胺日测表明，三氯胺浓度对泳客负荷的反应迅速而敏感，并且尿素可能不是其形成的主要前体。
