Disinfection by chloramination of water systems is an alternative to chlorination that is frequently used in North America. In such a case, monochloramine is used as the primary source of chlorine for disinfection. Regular monitoring of the residual concentrations of this species is crucial to ensure adequate disinfection. An amperometric sensor for monochloramine would provide fast, reagent free analysis, however the presence of dissolved oxygen in water complicates sensor development. In this work, we have explored the use of in-situ pH control as a method of eliminating oxygen as an interferent by conversion of monochloramine to dichloramine. The electrochemical reduction of dichloramine occurs outside the oxygen reduction window and is therefore not affected by oxygen concentration. Potential sweep methods were used to investigate the conversion of monochloramine to dichloramine at pH 3. The pH control method was used to calibrate monochloramine concentrations between 1 and 10 ppm, with a detection limit of 0.03 ppm. Tests were carried out in high alkalinity samples, wherein it was found that the sensitivity of this method effectively remained unchanged. Monochloramine was also quantified in the presence of common interferents (copper, phosphate and iron) which had no significant impact on the analysis

中文翻译：

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使用指间电极原位pH控制消除一氯胺电化学检测中的氧气干扰

通过水系统的氯化消毒可以替代北美经常使用的氯化方法。在这种情况下，一氯胺被用作消毒的主要氯源。定期监测该物种的残留浓度对于确保充分消毒至关重要。一氯胺的安培传感器将提供快速，无试剂的分析，但是水中溶解氧的存在使传感器的开发变得复杂。在这项工作中，我们探索了使用原位pH控制作为通过将一氯胺转化为二氯胺来消除作为干扰物的氧气的方法。二氯胺的电化学还原发生在氧气还原窗口之外，因此不受氧气浓度的影响。电位扫描法用于研究pH为3时单氯胺向二氯胺的转化。pH控制方法用于校准1至10 ppm之间的一氯胺浓度，检出限为0.03 ppm。在高碱度样品中进行了测试，发现该方法的灵敏度有效地保持不变。在存在常见干扰物（铜，磷酸盐和铁）的情况下，也对一氯胺进行了定量，这对分析没有重大影响