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文献[Anal.Chim.Acta,53,194(1971)]提出,偶氮胂Ⅲ在pH5.5条件下可与钙生成紫色络合物用于钙测定,且100倍量的镁、锰存在不干扰。本文采用六次甲基四铵—铜试剂分离干扰元素,制定出偶氮胂Ⅲ光度法测定地质试样中钙的方法,适于高镁岩矿样品中钙的分析。样品分析手续及结果称取矿样10～50毫克于铂坩埚中,加约1克过氧化钠,2～3粒氢氧化钠,在520℃半熔20分钟。热水提取熔块,加5毫升盐酸酸化,将溶液蒸发近干,加六次甲基四铵溶液(20%)5毫升,铜试剂(2%)5
The literature [Anal. Chim. Acta, 53, 194 (1971)] suggests that arsenazo III can form a purple complex with calcium at pH 5.5 for calcium determination and that 100-fold amounts of magnesium and manganese do not interfere. In this paper, hexamethylenetetramine-copper reagent was used to separate the interfering elements, and a method for the determination of calcium in geological samples by arsenazoⅢ spectrophotometry was developed. It is suitable for the analysis of calcium in high-magnesium rock samples. Sample analysis procedures and results Weigh 10 to 50 mg ore samples in a platinum crucible, add about 1 g of sodium peroxide, 2 to 3 sodium hydroxide, half-melt at 520 ° C for 20 minutes. Hot water extraction frit, add 5 ml of hydrochloric acid acidification, the solution was evaporated to near dryness, plus six times methyltetraamine solution (20%) 5 ml, copper reagent (2%) 5