Direct potable reuse requires stringent water quality assurance to protect public health. This study developed an online analytical technique—high-performance liquid chromatography followed by photochemical reaction and chemiluminescence detection (HPLC-PR-CL)—for determination of the concentration of N-nitrosodimethylamine (NDMA) and three other N-nitrosamines. Its feasibility for near real-time analysis was evaluated by analyzing an ultrafiltration (UF)-treated wastewater before and after a pilot-scale reverse osmosis (RO) treatment system. The online instrument with a method detection limit of 0.3–2.7 ng L⁻¹ requires a direct injection (i.e., no sample pre-concentration) of only 20–200 μL sample volume for the determination of N-nitrosamine concentrations every 20 min. NDMA concentrations in UF-treated wastewater were successfully monitored in a range of 50–200 ng L⁻¹ over the course of 24 h. Likewise, NDMA concentrations in RO permeate ranged from 26–81 ng L⁻¹ over the course of 48 h. The online monitor was capable of recording variations in N-nitrosamine concentration in RO permeate that occurred following changes in feedwater concentration and temperature. This study demonstrates the potential for online water quality assurance via direct measurement of trace levels of organic contaminants, which is highly relevant to the implementation of potable reuse.

中文翻译：

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近实时Ñ在饮用水重用-nitrosodimethylamine监测经由在线高效液相色谱法光化学反应的化学发光

直接的饮用水回用需要严格的水质保证，以保护公众健康。这项研究开发了一种在线分析技术-高效液相色谱，然后进行光化学反应和化学发光检测（HPLC-PR-CL）-用于确定N-亚硝基二甲胺（NDMA）和其他三种N-亚硝胺的浓度。通过在中试规模的反渗透（RO）处理系统之前和之后分析超滤（UF）处理的废水，评估了其近实时分析的可行性。方法检测极限为0.3–2.7 ng L ^-1的在线仪器仅需要直接进样（即无需样品预浓缩）即可获得20–200μL样品量。每20分钟N-亚硝胺浓度。在24小时内，用UF处理的废水中的NDMA浓度成功地在50–200 ng L ^-1的范围内进行了监测。同样，在48小时内，RO渗透物中的NDMA浓度范围为26–81 ng L ^-1。在线监控器能够记录由于给水浓度和温度的变化而发生的RO渗透物中N-亚硝胺浓度的变化。这项研究表明，通过直接测量痕量有机污染物的水平，在线水质保证的潜力与饮用水的再利用的实施高度相关。