铅镉重金属离子在铋膜电极上的相互影响

摘要

采用原位镀铋电极的方式,以玻碳电极为工作电极,通过改变Cd2+和Pb2+的比例,考察不同Pb2+和Cd2+浓度条件下,两者同时存在时的相互影响。实验发现,Cd2+和Pb2+同时存在时,存在相互的影响,特别是对于Cd2+的检测,由于Pb2+较正的析出电位,对于Cd2+的析出有一定的辅助作用。考察了Cd2+和Pb2+单独存在时的分析性能, Pb2+沉积时间为60 s时,在1~80μg/L范围内呈线性关系,检出限为0.5μg/L；Cd2+的沉积时间为120 s,在1~25μg/L和30~200μg/L范围内有良好的线性关系,检出限为1.0μg/L。考察了铋膜电极在不同实际水样中对Pb2+和Cd2+的分析,获得了较好的一致性。%The mutual influence of lead and cadmium ions on “in-situ” bismuth film coated glassy carbon electrode was demonstrated using different concentration target ions by changing ratio between Pb2+ and Cd2+. It is found that the presence of coexisting ions can have an influence on the detection of target ions. Especially for the detection of Cd2+, the existence of Pb2+ can be beneficial for the deposition of Cd due to the more positive deposition potentials. And the analytical performances of Cd2+and Pb2+ were obtained. The detection limit is 0. 5 μg/L towards Pb2+ with a linear range from 1-80 μg/L using 60 s deposition time. The resulting calibration plots of Cd2+ are linear over the range from 1-25 and 30-200 μg/L with the detection limit of 1 μg/L using 120 s deposition time. The bismuth film was finally employed to determine the Pb2+and Cd2+in real sample with good satisfied results.