食品添加剂植酸钠中无机磷含量测定研究

Determination of inorganic phosphorus in food additive sodium phytate

建立了一种食品添加剂植酸钠中无机磷含量的测定方法。本文对经典钼黄法进行改进,采用"三氯化铁去除基质效应"再用钼黄法测定无机磷含量,首先向植酸钠样品溶液中加入三氯化铁溶液,使其形成沉淀,高速离心弃去沉淀后再加入钒钼酸铵溶液,生成黄色的磷钒钼酸配合物,用分光光度计在420nm处测其吸光值,再根据标准曲线计算样品中无机磷含量。结果表明,当无机磷添加浓度为0.02%～0.08%时,回收率范围在99.0%～102.48%之间,相对标准偏差在1.03%～1.16%之间,方法学指标满足《GB/T 27404-2008实验室质量控制规范食品理化检测》的要求。

A method for the determination of inorganic phosphorus in sodium phytate was established. In this paper,'iron trichloride removing matrix effect' was used ?rst and then followed by molybdenum yellow method.Ferric chloride solution was added to the sodium phytate sample solution to form precipitation. After high-speed centrifugation,the precipitation was discarded and ammonium vanadium molybdate solution was then added to form yellow phosphorus vanadium molybdate complex. The absorbance value was measured at 420 nm by spectrophotometer. The inorganic phosphorus content in the sample was calculated according to the standard curve.The results were :inorganic phosphorus content 0.02%~0.08%,the recovery rate 99.0%~102.48%,and relative standard deviation 1.03%~1.16%. The methodological indexes met the requirements of GB/T 27404-2008 Laboratory Quality Control Standard for Food Physicochemical Testing.