2018 年 67 巻 12 号 p. 761-766
Anodic stripping voltammetry (ASV) is a highly sensitive method, especially for the determination of Cd2+ and Pb2+. However, it is known that organic matter in sample, such as soil extract, interfere negatively. In the present study, an electrodialytic ion trasfer deveice (ITD) was used for the sample pretreatment of soil extract to determine Cd2+ and Pb2+ by ASV. Hydrochloric acid needed to be used for ASV with a bithmas film electrode (BiFE). Thus, the ITD conditions were optimized with HCl and the obtained transfer efficiency for Cd2+ and Pb2+ was 97.5±5.8 % and 101±3 %, respectively with an analyte concentration of 10 μg L−1. Furthermore, ASV with BiFE conditions were optimized with a flow-through electrochemical cell. The HCl concentration of sample was required to be at least 0.3 M. The highest response was obtained with 0.5 M. This concentration was 10-times higher than the optimized concentration on ITD. Thus, the effluent of ITD was once trappted in micro-tube, followed by the addition of the concentration of HCl to adjust to the optimized concentration for ASV. In the developped system, the soil extract sample can be handled automatically from the ITD pretreatment to the ASV analysis while avoiding any contaminations. The real soil extract was evaluated with the standard addition test. The effects of the ITD pretreatment effectively worked for avoiding any interferences by organic matter. The recovery values with the ITD pretreatment for Cd2+ and Pb2+ were 105 and 100 % ; even without any ITD pretreatment they were 6.0 and 91 %, respectively. This results prove that the ITD pretreatment is effective for soil extract analysis with ASV.