巯基棉分离富集光度法测定垃圾渗滤液中镉的含量

在酸性条件下,甲基紫(MV)-亚硝基R盐(NRS)与Cd(Ⅱ)发生显色反应生成具有正、负吸收峰的紫色三元络合物.其最大吸收波长位于634(正吸收)和566 nm(负吸收),线性范围为0~2.65(正吸收)和0~2.90μg.mL-1(负吸收),表观摩尔吸光系数ε为1.13×104(正吸收)和2.18×104L.mol-1.cm-1(负吸收).若采用双波长叠加测定,灵敏度更高(ε为3.30×104L.mol-1.cm-1).探讨了反应条件、主要分析化学性质及三元缔合物的配位比.结合巯基棉分离富集方法,该体系用于垃圾渗滤液中镉的测定,结果满意.

The Determination of Cadmium in Garbage Percolate by Spectrophotometry with Sulfhydryl Cotton Seperation and Preconcentration

In acid conditions,Cadmium (Ⅱ) reacts with methyl violet(MV)- nitroso-R-salt(NRS) to form ternary purple association complexes with positive and negative absorption peaks.The maximum absorption wavelength is at 634 nm (positive absorption) and 566 nm (negative absorption),the linear ranges are 0-2.65 μg/mL (positive absorption) and 0-2.90 μg·mL~(-1) (negative absorption),and their apparent molar absorptivities (ε) are 1.13×10~4 L·mol~(-1)·cm~(-1) (positive absorption) and 2.18×10~4 L·mol~(-1)·cm~(-1) (negative absorption).When the positive and negative wavelengths overlapping absorption spectrometry is used to determine the concentrations of cadmium,their sensitivity is much higher(ε was 3.30×10~4 L·mol~(-1)·cm~(-1)).The optimum reaction conditions,the chief properties of analytical chemistry and the compound ratio of ternary association complexes have been discussed.Compared with the method of sulfhydryl cotton seperation and preconcentration,the system has been applied to determine the content of cadmium in garbage percolate with satisfactory results.