分光光度法测定菠菜中草酸盐总量

DETERMINATION OF TOTAL OXALATE IN SPINACH BY SPECTROPHOTOMETRY

菠菜中的草酸在碱性条件下以草酸钙((CaC_2O_4)形式沉出。离心,弃去上清液。然后调至酸性,加入高锰酸钾(KMnO_4),用固定时间法,在525nm处测出吸光度,计算草酸盐的含量。对于干扰较为严重的有机物,采用紫外光照射的方法进行排除。此法的特点是取消了一般沉淀处理中的沉淀、分离、洗涤等繁琐步骤,使前处理简单易行;测得草酸根(C_2O_4^(2-))的范围为2～35μg/ml。变异系数为5.35％。回收率为93％～105％

An improved method for determination of the total oxalate in spinach was proposed. Oxalate in the spinach was precipitated at alkaline in CaC2O4 form. The precipitate was obtained by centrifugation and then acidified by HCIO4. KMnO4 was added and absorptivity was determined at 525 nm at a fixed time. This method was accurate and simple. Organic impurities existed in spinach could be removed by ultrviolet ray. The range of determination was 2μg/ml-35μg/ml. The recovery rate was 93-105% and the coefficient of variation was less than 5.35%.