对乙酰基偶氮氯膦光度法测定烟草中钙的方法研究

Study on Spectrophotometric Determination of Calcium in Tobacco with p-Acetylchlorophosphonazo

研究了对乙酰基偶氮氯膦 ( ACCPP)与钙的显色反应 ,在 p H=8.5的氯化铵 -氨水缓冲介质中 ,乳化剂 - OP存在下 ,ACCPP与钙反应生成 1∶ 1稳定络合物 ,λmax=680 nm,ε=4 .0 1× 10 4 L· mol-1· cm-1。钙含量在 0— 2 0μg/2 5m L范围内符合比耳定律 ,方法用于烟草样品中钙含量的测定 ,结果令人满意。

Color reaction of calcium(Ⅱ) with p-acetylchlorophosphonazo (ACCPP) was studied.In the presence of buffer solution pH=8.5 ACCPP can react with calcium(Ⅱ) to form a stable 1∶1 complex.The molar absorptivity is 4.01×10~4L·mol^-1·cm^-1 at 680nm.Beer's law is obeyed in the range of 0—20μg/25mL.This method was applied to the determination of calcium in tobacco with satisfactory results.