Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA.
Analyst. 2022 Jul 22;147(15):3542-3557. doi: 10.1039/d2an00724j.
Exposure to lead, a toxic heavy metal, in drinking water is a worldwide problem. Lead leaching from lead service lines, the main contamination source, and other plumbing materials is controlled by the plumbosolvency of water. Square wave anodic stripping voltammetry (SWASV) has been greatly explored as a rapid and portable technique for the detection of trace Pb ions in drinking water. However, the impact of water quality parameters (WQP) on the SWASV technique is not well understood. Herein, SWASV was employed to detect 10 μg L Pb and determine trends in the stripping peak changes in simulated water samples while individually varying the pH, conductivity, alkalinity, free chlorine, temperature, and copper levels. The pH and conductivity were controlled using the buffer 3-(-morpholino)propanesulfonic acid (MOPS), and NaNO, respectively and kept at pH = 7.0 and conductivity = 500 μS cm when exploring other WQPs. The working electrode, a gold-nanoparticle-modified carbon nanotube fiber cross-section (AuNP-CNT-CS) electrode provided sufficiently sharp and prominent peaks for 10 μg L Pb detection as well as good reproducibility, with a relative error of 5.9% in simulated water. We found that conductivity, and temperature had a proportional relationship to the peak height, and pH, alkalinity, free chlorine, and copper had an inverse relationship. In addition, increasing the copper concentration caused broadening and shifting of the Pb stripping peak. At extremely low conductivities (<100 μS cm), the voltammograms became difficult to interpret owing to the formation of inverted and distorted peaks. These trends were then also observed within a local drinking water sample in order to validate the results.
饮用水中铅的暴露是一个全球性的问题，铅是一种有毒的重金属。从铅服务管道（主要污染源）和其他管道材料中浸出的铅通过水的溶铅能力来控制。方波阳极溶出伏安法（SWASV）已被广泛探索作为一种快速便携的技术，用于检测饮用水中的痕量 Pb 离子。然而，水质参数（WQP）对 SWASV 技术的影响还不是很清楚。在此，采用 SWASV 检测 10 μg L 的 Pb，并在模拟水样中单独改变 pH 值、电导率、碱度、游离氯、温度和铜水平时，确定了析脱峰变化的趋势。pH 值和电导率分别使用缓冲液 3-(- 吗啉代)丙磺酸（MOPS）和 NaNO3 控制，并在探索其他 WQP 时将 pH 值保持在 7.0，电导率保持在 500 μS cm。工作电极是一种金纳米粒子修饰的碳纳米管纤维横截面（AuNP-CNT-CS）电极，它为 10 μg L 的 Pb 检测提供了足够尖锐和突出的峰以及良好的重现性，在模拟水中的相对误差为 5.9%。我们发现，电导率和温度与峰高成正比，而 pH 值、碱度、游离氯和铜与峰高成反比。此外，增加铜浓度会导致 Pb 析脱峰的展宽和位移。在极低的电导率（<100 μS cm）下，由于形成了倒置和扭曲的峰，伏安图变得难以解释。这些趋势也在当地的饮用水样本中得到了验证，以验证结果。
