超高灵敏显色反应及其应用的研究Ⅷ.铅-乙基罗丹明B-碘化物体系

Studies on Superhighly Sensitive Color Reactions and Their Applications Ⅷ. Lead-Ethylrhodamine B-Iodide System

本文研究了在聚乙稀醇-阿拉伯胶共存下,乙基罗丹明B和PbI_4^(2-)的超高灵敏显色反应并制定了新的光度法。缔合物最大吸收为605nm,ε值为1.0×10~6·L·mol^(-1)·cm^(-1)。经巯基棉分离、富集,本法成功地用于硫酸镁、硫酸锌和硫酸亚铁铵等试剂中痕量铅的测定。

A highly sensitive spectrophotometric method has been developed for the determination of trace lead, based on the formation of a complicated ion-association complex of lead (Ⅰ) with ethyirhodamine B and iodide in the presence of polyvinyl alcohol and Arabic gum. The maximum absorption of the ion-association complex is at 605nm, and its apparent molar absorptivity is 1.0×10~6 L.mol^(-1).cm^(-1).Beer's law is obeyed in the range of 0.1～3.0μg/25ml for lead. The interference of 20 diverse ions was studied. The proposed method has been used for the determination of trace lead in chemical reagents with satisfactory results.