亚铜离子选择性电极测定硫氰酸根
Determination of Thiocyanate with Cuprous Ion Selective Electrode
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摘要: 采用液体石蜡作为粘合剂,将2,9-二甲基-4,7-二苯基-1,10二氮菲(又名向红亚铜灵)与碳粉混合作为电极敏感膜,制备了新型亚铜离子选择性电极。基于亚铜离子和SCN-可生成稳定络合物,提出了用上述电极间接测定样品中硫氰酸根含量的方法。试验表明:在pH 6.2的0.01 mol·L-1柠檬酸钠溶液中,电极电位呈现能斯特响应,间接以SCN-的浓度表示的线性范围为1.0×10-7~1.0×10-3mol·L-1。将该电极用于化工废水中硫氰酸根的测定,用标准加入法做回收试验,测得回收率在96.7%~101%之间,相对标准偏差(n=7)在2.2%~5.5%之间。Abstract: A new Cu(Ⅰ)-selective electrode was prepared by using a mixture of bathocuproin and carbon paste as sensitive film and paraffin wax as binder. Based on the formation of a stable complex between SCN- and Cu+, an indirect method for determination of SCN- with the Cu(Ⅰ)-selective electrode was proposed. It was found that in 0.01 mol·L-1 sodium citrate solution of pH 6.2 excellent selectivity and potential response toward SCN- (indirectly) were achieved by the ion selective electrode, which showed Nernst potential response in the range of 1.0×10-7 to 1.0×10-3mol·L-1 SCN-. Recovery was tested by standard addition method using sample of chemical waste water as matrixes, results of recovery found were in the range of 96.7%-101% with RSD′s (n=7) in the range of 2.2%-5.5%.