Department of Chemistry, University of Cincinnati, Cincinnati, OH, 45221, United States.
AOSmith Corporation, Milwaukee, WI, United States.
Anal Chim Acta. 2021 Apr 22;1155:338353. doi: 10.1016/j.aca.2021.338353. Epub 2021 Feb 26.
Heavy metal contamination of drinking water is a major global issue. Research reports across the globe show contamination of heavy metals higher than the set standards of the World Health Organization (WHO) and US Environmental Protection Agency (EPA). To our knowledge, no electrochemical sensor for heavy metals with parts per trillion (PPT) limits of detection (LOD) in as-is tap water has been reported or developed. Here, we report a microelectrode that consists of six highly densified carbon nanotube fiber (HD-CNTf) cross sections called rods (diameter ∼69 μm and length ∼40 μm) in a single platform for the ultra-sensitive detection of heavy metals in tap water and simulated drinking water. The HD-CNTf rods microelectrode was evaluated for the individual and simultaneous determination of trace level of heavy metal ions i.e. Cu, Pb and Cd in Cincinnati tap water (without supporting electrolyte) and simulated drinking water using square wave stripping voltammetry (SWSV). The microsensor exhibited a broad linear detection range with an excellent limit of detection for individual Cu, Pb and Cd of 6.0 nM, (376 ppt), 0.45 nM (92 ppt) and 0.24 nM (27 ppt) in tap water and 0.32 nM (20 ppt), 0.26 nM (55 ppt) and 0.25 nM (28 ppt) in simulated drinking water, respectively. The microelectrode was shown to detect Pb ions well below the WHO and EPA limits in a broad range of water quality conditions reported for temperature and conductivity in the range of 5 °C-45 °C and 55 to 600 μS/cm, respectively.
饮用水中的重金属污染是一个全球性的重大问题。全球各地的研究报告显示，重金属污染超过了世界卫生组织（WHO）和美国环境保护署（EPA）设定的标准。据我们所知，目前还没有报道或开发出用于检测自来水中重金属的具有万亿分之一（ppt）级检测限（LOD）的电化学传感器。在这里，我们报告了一种由六个高密度碳纳米管纤维（HD-CNTf）横截面组成的微电极，称为棒（直径约为 69μm，长度约为 40μm），用于在单个平台上超灵敏地检测自来水中的重金属和模拟饮用水。使用方波 stripping 伏安法（SWSV），我们评估了 HD-CNTf 棒微电极对辛辛那提自来水（无支持电解质）和模拟饮用水中痕量重金属离子（如 Cu、Pb 和 Cd）的单独和同时测定。该微传感器对个体 Cu、Pb 和 Cd 的检测范围很广，在自来水中的检测限分别为 6.0 nM（376 ppt）、0.45 nM（92 ppt）和 0.24 nM（27 ppt），在模拟饮用水中的检测限分别为 0.32 nM（20 ppt）、0.26 nM（55 ppt）和 0.25 nM（28 ppt）。该微电极在较宽的水质条件范围内（报告的温度和电导率范围分别为 5°C-45°C 和 55 至 600 μS/cm），能够检测到低于 WHO 和 EPA 标准的 Pb 离子。
