警报型即时检测自来水体中铅含量的方法研究

Method of Lead Detection in Tap Water by Alert-type Point-ofcare Test

以Bi(Ⅲ)做内标,结合丝网印刷电极与微型化的电化学检测系统,建立了一种警报型即时检测方法,可以对自来水中铅含量是否超标进行快速准确的判断。采用方波溶出伏安法测定了含10μg/L铅标准溶液的IPb/IBi并计算得出阈值。讨论了3种电极预处理方法以及不同浓度Cu2+对IPb/IBi测定的干扰与消除。实验结果表明:电极经1.8 V阳极氧化处理2 min后,电子转移电阻大大减小,由4 348Ω减小至715Ω,峰电流增加1.6倍,峰电位之差△Ep由212 m V减小至113 m V。当加入2.0 mmol/L Fe(CN)64-,Cu2+干扰可有效消除。将这种方法用于自来水样的IPb/IBi测定,与阈值对比给出Yes/No判断结果,通过ICP-MS验证方法的有效性,结果令人满意。作为一种简捷、快速和便携的检测平台,该方法无需测出Pb2+的准确浓度,具有巨大的应用潜力。

Combined with screen printed electrode and custom USB electrochemical system（μECS）, bismuth served as internal standard is used for the construction of alert-type point-of-care testing method to decide whether the lead level has excessed a regulated threshold. The threshold is obtained by determining standard solution containing 10 μg/L Pb^2 ＋with square wave anodic stripping voltammetry（SWV）. Three electrode pretreatment methods as well as the interference and removal of Cu^2＋were discussed. Results indicated that a remarkable decreased charge transfer resistance from 4 348 Ω to 715Ω was observed after electrode was pretreated at 1.8 V for 2 min and the peak current increased 1.6-fold with peak potential separation decreasing from 212 m V to 113 m V. The detrimental effect of Cu^2＋can be circumvented effectively by adding 2.0mmol/L Fe（CN）6^4-. The proposed method is applied to the decision of Pb2＋in tap water samples and to give a Yes/No signal.ICP-MS analysis is performed to validate the reliability, and the results are satisfying. Simple, rapid and portable, the platform holds great potential for the application in daily life.