间氯偶氮安替比林光度法测定烟草中的钙

Spectrophotometric Determination of Calcium in Tobacco with m-Chloroantipyrylazo

摘要: 研究了用间氯偶氮安替比林分光光度法测定烟草中钙的方法。在碱性介质中,钙与间氯偶氮安替比林形成1:1的蓝色配合物,其最大吸收波长为630nm,表观摩尔吸光系数为2.6×10⁴ L·mol^-1·cm^-1,钙含量在0~40μg/25mL范围内符合比尔定律。烟草中的其它矿物成分对测定不产生干扰,与传统的EDTA滴定法相比具有灵敏度高、选择性好、简便快速等优点,用于测定烟草中的钙,其回收率为96.2%~99.3%,RSD为2.8%。

Abstract: A spectrophotometric method for the determination of calcium in tobacco with m-chloroantipyrylazo was studied.In the sodium hydroxide solution medium, a blue complex was formed by Ca²⁺ with the chromogenic reagent, which had a maximum absorption at wavelength of 630nm, and an apparent molar absorptivity of 2.6×10⁴ L·mol^-1·cm^-1.The calibration curve was a straight line when the concentration of Ca²⁺ was in the range of zero to 40μg/25mL.Other metallic cations in tobacco did not interfere with the determination of Ca²⁺.The average recovery of this method was between 96.2% to 99.3% and RSD was 2.8%.