新试剂二溴邻羧基偶氮氯膦作镁、稀土的显色剂 Ⅰ.光度测定镁的研究和应用

A New Reagent Dibromocarboxychlorophosphonazo as a Chromogenic Reagent for Magnesium and Rare Earths I. Study on the Spectrophotometric Determination of Magnesium and Its Application

本文研究了新显色剂二溴羧基偶氮氯膦与镁的反应条件。在pHl0.5NH_3·H_2O-NH_4Cl缓冲浪中试剂与镁生成蓝色配合物,其最大吸收峰在615nm处,摩尔吸光系数为1.9×10~4L/mol·cm,镁量在0～16μg/25ml范围内符合比尔定律。在三乙醇胺、Zn-EGTA、邻啡罗啉等掩蔽剂存在下,具有较好的选择性。应用于硅镁合金和球墨铸铁中镁的测定获得满意的结果。

In this paper, the colour reaction of magnesium with dibromocarboxychtorophosphonazo has been studied. Magnesium reacts with reagent in pH10.5 NH3 HaO-NH4Cl medium to form a blue complex which has a maximum absorption at 615nm. Under the experimental conditions employed, the apparent molar absorptivity is 1.9xl04L mol-1 cm-1 ?Beer's law is obeyed for 0-16ug in 25ml of solution. The reaction shows higher selectivity in the presence of a mixture of triethanolamine, Zn-EDTA and o-phenanthroline. This method has been applied to determine magnesium in silicon-magnesium alloys and nodular cast iron with satisfactory results.