论文部分内容阅读
研究了铅-钼-偶氮胂Ⅲ异金属双核三元络合物体系的光度分析性质,建立了测定微量铅的最佳条件。络合物的最大吸收峰位于660nm(对试剂空白),在pH2.5～4.5有恒定的吸光值。三元体系较其二元体系(无钼存在时)有较高的灵敏度与选择性。表观摩尔吸光系数ε_(660nm)=3.0×10~4,0～50μg Pb/25ml遵守比耳定律。在有钼酸铵及EDTA-Zn溶液存在下,大多数金属离子均不干扰微量铅的测定。方法用于锌及锌铝合金中微量铅的直接测定,获得了满意的结果。
The photometric analysis of the lead-molybdenum-arsenazo Ⅲ heterometallic binuclear ternary complex system was studied and the optimum conditions for the determination of trace lead were established. The maximum absorption peak of the complex was at 660 nm (blank for the reagent) with a constant absorbance at pH 2.5-4.5. The ternary system has higher sensitivity and selectivity than the binary system (without molybdenum). Apparent molar absorptivity ε 660nm = 3.0 × 10-4,0 ~ 50μg Pb / 25ml obeys Beer’s law. In the presence of ammonium molybdate and EDTA-Zn solution, most metal ions do not interfere with the determination of trace lead. The method was applied to the direct determination of trace lead in zinc and zinc-aluminum alloys and obtained satisfactory results.