Abstract：
BACKGROUND: Nitrite (NO2-) and nitrate (NO3-) can be produced in the distribution systems of chloraminated drinking water due to the nitrification of ammonia. The most applied inorganic chloramine for this purpose, namely monochloramine (NH2Cl), is also released into aquatic environments from water treatment plants\' effluent and within industrial waste streams. Within the treatment process, the continuous monitoring of disinfectant levels is necessary to limit the harmful disinfectant by-product (DBP) formation. Currently, NH2Cl can interfere with nutrient analysis in water samples, and there are no analytical techniques available for the simultaneous analysis of NH2Cl, NO2-, and NO3-.
RESULTS: A green analytical method based on mixed-mode ion chromatography, specifically ion exchange and ion exclusion modes, was developed for the simultaneous separation and detection of NH2Cl, NO2-, and NO3-. The separation was achieved using a Dionex IonPac AG15 column guard column and a step gradient elution involving deionized water and 120.0 mM NaCl. The method was developed using a benchtop HPLC with a custom-made multi-wavelength UV absorbance detector with a 50-mm flow cell to enable the sensitive detection of NH2Cl, NO2-, and NO3- at 240 nm, 220 nm, and 215 nm, respectively. The developed method was then transferred to a portable ion chromatography (IC) system, the Aquamonitrix analyser. The total run time was less than 10 min for both systems. The benchtop HPLC method had a limit of detection (LOD) of 0.07 μg mL-1 as Cl2 for NH2Cl, 0.01 μg mL-1 for NO2-, and 0.03 μg mL-1 for NO3-. The LODs obtained using the portable Aquamonitrix analyser were found to be 0.36 μg mL-1 as Cl2, 0.02 μg mL-1, and 0.11 μg mL-1 for NH2Cl, NO2-, and NO3-, respectively. Excellent linearity (r ≥ 0.9999) was achieved using the portable analyser over the studied concentration ranges. The developed system was applied to the analysis of spiked municipal drinking water samples and showed excellent repeatability for the three analytes at three different concentration levels (RSD of triplicate recovery experiments ≤ 1.9 %). Moreover, the variation in retention time was negligible for the three target analytes with RSD ≤ 0.8 % over 12 runs.
CONCLUSIONS: We are reporting the first ion chromatographic method for the simultaneous separation and detection of NH2Cl, NO2-, and NO3- in water samples. The monitoring of NH2Cl, NO2-, and NO3- is critical for the determination of disinfectant dosing, water quality, and nitrification status. The developed method can be applied using a benchtop HPLC or via the portable automated IC system to monitor for the three target compounds analysis in water treatment plants.
RESULTS: A green analytical method based on mixed-mode ion chromatography, specifically ion exchange and ion exclusion modes, was developed for the simultaneous separation and detection of NH2Cl, NO2-, and NO3-. The separation was achieved using a Dionex IonPac AG15 column guard column and a step gradient elution involving deionized water and 120.0 mM NaCl. The method was developed using a benchtop HPLC with a custom-made multi-wavelength UV absorbance detector with a 50-mm flow cell to enable the sensitive detection of NH2Cl, NO2-, and NO3- at 240 nm, 220 nm, and 215 nm, respectively. The developed method was then transferred to a portable ion chromatography (IC) system, the Aquamonitrix analyser. The total run time was less than 10 min for both systems. The benchtop HPLC method had a limit of detection (LOD) of 0.07 μg mL-1 as Cl2 for NH2Cl, 0.01 μg mL-1 for NO2-, and 0.03 μg mL-1 for NO3-. The LODs obtained using the portable Aquamonitrix analyser were found to be 0.36 μg mL-1 as Cl2, 0.02 μg mL-1, and 0.11 μg mL-1 for NH2Cl, NO2-, and NO3-, respectively. Excellent linearity (r ≥ 0.9999) was achieved using the portable analyser over the studied concentration ranges. The developed system was applied to the analysis of spiked municipal drinking water samples and showed excellent repeatability for the three analytes at three different concentration levels (RSD of triplicate recovery experiments ≤ 1.9 %). Moreover, the variation in retention time was negligible for the three target analytes with RSD ≤ 0.8 % over 12 runs.
CONCLUSIONS: We are reporting the first ion chromatographic method for the simultaneous separation and detection of NH2Cl, NO2-, and NO3- in water samples. The monitoring of NH2Cl, NO2-, and NO3- is critical for the determination of disinfectant dosing, water quality, and nitrification status. The developed method can be applied using a benchtop HPLC or via the portable automated IC system to monitor for the three target compounds analysis in water treatment plants.
摘要：
背景：由于氨的硝化作用，可以在氯胺化饮用水的分配系统中产生亚硝酸盐（NO2-）和硝酸盐（NO3-）。最常用的无机氯胺，即一氯胺（NH2Cl），也从水处理厂的废水和工业废物流中释放到水生环境中。在治疗过程中,连续监测消毒剂水平是必要的，以限制有害消毒剂副产物（DBP）的形成。目前,NH2Cl会干扰水样中的营养素分析，并且没有可用于同时分析NH2Cl的分析技术，NO2-,和NO3-。
结果：基于混合模式离子色谱法的绿色分析方法，特别是离子交换和离子排斥模式，用于同时分离和检测NH2Cl，NO2-,和NO3-。使用DionexIonPacAG15柱保护柱和包括去离子水和120.0mMNaCl的分步梯度洗脱来实现分离。该方法是使用台式HPLC开发的，该HPLC具有定制的多波长UV吸光度检测器，该检测器具有50毫米的流动池，可以灵敏地检测NH2Cl，NO2-,和NO3-在240纳米，220nm,和215纳米，分别。然后将开发的方法转移到便携式离子色谱（IC）系统中，Aquamonitrix分析仪.两种系统的总运行时间均小于10分钟。台式HPLC方法对NH2Cl的Cl2的检出限（LOD）为0.07μgmL-1，对于NO2-，0.01μgmL-1，NO3-为0.03μgmL-1。发现使用便携式Aquamonitrix分析仪获得的LOD为Cl2为0.36μgmL-1，NH2Cl为0.02μgmL-1和0.11μgmL-1，NO2-,和NO3-，分别。在研究的浓度范围内，使用便携式分析仪可实现出色的线性度（r≥0.9999）。开发的系统用于加标的市政饮用水样品的分析，并在三种不同浓度水平下对三种分析物表现出出色的可重复性（一式三份回收实验的RSD≤1.9％）。此外，对于RSD≤0.8%的3种目标分析物,在12次运行中,保留时间的变化可以忽略不计.
结论：我们正在报告第一种同时分离和检测NH2Cl的离子色谱法，NO2-,和水样品中的NO3-。NH2Cl的监测，NO2-,和NO3-对于确定消毒剂的剂量至关重要，水质,和硝化状态。所开发的方法可以使用台式HPLC或通过便携式自动IC系统应用，以监测水处理厂中的三种目标化合物分析。
结果：基于混合模式离子色谱法的绿色分析方法，特别是离子交换和离子排斥模式，用于同时分离和检测NH2Cl，NO2-,和NO3-。使用DionexIonPacAG15柱保护柱和包括去离子水和120.0mMNaCl的分步梯度洗脱来实现分离。该方法是使用台式HPLC开发的，该HPLC具有定制的多波长UV吸光度检测器，该检测器具有50毫米的流动池，可以灵敏地检测NH2Cl，NO2-,和NO3-在240纳米，220nm,和215纳米，分别。然后将开发的方法转移到便携式离子色谱（IC）系统中，Aquamonitrix分析仪.两种系统的总运行时间均小于10分钟。台式HPLC方法对NH2Cl的Cl2的检出限（LOD）为0.07μgmL-1，对于NO2-，0.01μgmL-1，NO3-为0.03μgmL-1。发现使用便携式Aquamonitrix分析仪获得的LOD为Cl2为0.36μgmL-1，NH2Cl为0.02μgmL-1和0.11μgmL-1，NO2-,和NO3-，分别。在研究的浓度范围内，使用便携式分析仪可实现出色的线性度（r≥0.9999）。开发的系统用于加标的市政饮用水样品的分析，并在三种不同浓度水平下对三种分析物表现出出色的可重复性（一式三份回收实验的RSD≤1.9％）。此外，对于RSD≤0.8%的3种目标分析物,在12次运行中,保留时间的变化可以忽略不计.
结论：我们正在报告第一种同时分离和检测NH2Cl的离子色谱法，NO2-,和水样品中的NO3-。NH2Cl的监测，NO2-,和NO3-对于确定消毒剂的剂量至关重要，水质,和硝化状态。所开发的方法可以使用台式HPLC或通过便携式自动IC系统应用，以监测水处理厂中的三种目标化合物分析。
