土壤铅和镉溶出伏安法检测中影响因素及其削弱方法研究进展

溶出伏安法具有分析速度快、成本低、灵敏度高等优点被广泛应用于检测土壤重金属含量，但在检测土壤重金属时，溶出伏安检测精度会受到多方面因素的影响。该文在介绍溶出伏安法工作原理的基础上，从伏安参数、试验条件和土壤物质成分三方面阐述溶出伏安法检测土壤Pb2+和Cd2+为的影响因素，解析各因素的影响机理，归纳影响削弱方法的研究进展。研究结论为：方波脉冲阳极溶出伏安法最常用于检测土壤Pb2+和Cd2+，伏安参数包括脉冲幅值、电压增量和脉冲频率，试验条件包括沉积时间、沉积电压和支持电解质种类及其pH值，土壤成分主要干扰因素包括非目标重金属和有机质。针对伏安参数和试验条件的影响可以设计优化试验有效削弱。针对非目标重金属和有机质的干扰影响，目前研究还没有提出有效的削弱方法。最后，展望了溶出伏安法检测土壤重金属的未来发展方向。

Research advances of influencing factors and weakening methods to determine Pb2+ and Cd2+ in soils by anodic stripping voltammetry

Abstract: Pb2+ and Cd2+ are non-biodegradable heavy metal elements with high toxicity. They, even at trace levels, can cause serious damage to the brain, kidneys, blood, nerves, and other organs. Improper human activities have deposited a large amount of Pb2+ and Cd2+ into the soil, such as sewage irrigation, the abuse of chemical fertilizers and pesticides, as well as the excessive discharge of industrial wastes. The heavy metal ions have inevitably been absorbed by crops and then accumulated in animals. After that, these heavy metals can be enriched thousands of times into the human body, ultimately endangering human health, particularly under the biomagnification of food chain. Therefore, rapid, accurate, and reliable detection of Pb2+ and Cd2+ in soil has been highly urgent to control heavy metal pollution for product safety in modern agriculture. One of electrochemical technique, Anodic Stripping Voltammetry (ASV) can be used for on-site and real-time detection of Pb2+ and Cd2+ in soils, indicating high sensitivity, excellent selectivity, convenient operation, equipment portability, and low cost. However, ASV is susceptible to various influencing factors, leading to the decrease in the accuracy of heavy metals detection. The detection performance also varies in the different ASVs. According to the type of voltammetric signal, ASV can be divided into square-wave anodic stripping voltammetry (SWASV), Differential Pulse Anodic Stripping Voltammetry (DPASV), and Linear Anodic Sweep Voltammetry. Among them, SWASV and DPASV are often used to detect Pb2+ and Cd2+ in soils, due to their higher sensitivity and lower detection limit. Voltammetric parameters negatively influence the stripping peak current of Pb2+ and Cd2+, including pulse amplitude, pulse frequency, and potential increment. Furthermore, the voltammetric response of target heavy metals depends seriously on experimental conditions, such as supporting electrolyte type and pH value, deposition potential, as well as deposition time. More importantly, there is the complex composition in soils, including a variety of metal cations, anions, and rich organic matter, but the content of heavy metal ions is very low. Therefore, the voltammetric signal of heavy metals is relatively weak, particularly that easily interfered with by the complex components in soils. In addition, Cu2+ and organic matter are the most common and serious interference factors in soil. In this review, the interference problem of Cu2+ was proposed for an efficient Cu2+ interference suppression. Moreover, a specific mechanism was also addressed to explore the interference of soil humus on the practical application of Pb2+ and Cd2+ detection using ASV. Sensitive material modified-electrodes were selected to obtain high signal-to-noise ratio voltammetric signals in recent years. Although these materials improve the sensitivity, selectivity, and stability of electrodes, the complex composition in soils will interfere with the detection performance of electrodes, and the amount of material modification, where the concentration of sensitive materials will also interfere with the voltammetric signal of target heavy metals. To accurate and reliably detect Pb2+ and Cd2+ in soils using ASV, the following problems must be solved in future research: 1) To propose an efficient suppression of Cu2+ interference. 2) To explore the interference mechanism of soil humus on Pb2+ and Cd2+ detection, aiming to an efficient suppression of interference, and 3) To develop modified materials with high selectivity and stability, thereby to improve the detection performance of electrodes for Pb2+ and Cd2+. Summarily, the working principle of various ASVs was firstly introduced to analyze the influencing factors on Pb2+ and Cd2+ detection using ASV from three aspects of voltammetric parameters, experimental conditions, and soil material composition. Then, the influencing mechanism of each factor was explained to summary the research advances of influence mitigation. Finally, this finding can provide a promising future of interference research during the detection of Pb2+ and Cd2+ in soils using ASV.