摘要
本文建立了对羧基偶氮羧分光光度法测定微量钙的方法,研究了试剂与钙的β型显色反应的条件、影响因素及形成机理。在柠檬酸介质中,钙与该试剂只发生灵敏的β型显色反应,络合物最大吸收波长为718nm(△λ=157nm),表观摩尔吸光系数ε=1.51×10~5L·mol^(-1)·cm^(-1),反应完全后,吸光度可保持4h不变。方法用于直接测定复方氯化钠注射液中的钙,回收率在99.20％～103.5％之间,结果与标准方法一致,相对标准偏差小于1.5％。
The β-type colour reaction between calcium and p-carboxycarboxylazo in citric acid medium and its mechanism are described. A selective and sensitive method for the direct spectrophotometric determination of calcium in compound sodium chloride injection is developed. Calcium reacts with p-carboxycarboxylazo to form only a highly sensitive and stable β-type complex with λ_(m a x)=718nm (Δλ=157nm), e=1.51×10~5L·mol^(-1)·cm^(-1). The complex formation is complete within 15min in a small volume and the resulting complex is stable for 4h after dilution, Four real samples were analyzed by the proposed method. The results agreed well with calcium contents in the samples obtained by using the standard method and their relative standard deviations were less than 1.5%. THe average recovery of calcium for samples was 99.20%～103.5%.
出处
《分析化学》
SCIE
EI
CAS
CSCD
北大核心
1992年第11期1235-1238,共4页
Chinese Journal of Analytical Chemistry
关键词
钙
对羧基偶氮羧
显色反应
Calcium
p-Carboxycarboxylazo
Colour reaction
