电位滴定法测定桔汁饮品中抗坏血酸含量研究初报

Determination of the content of vitmin C in the citrus juice beverage by the potentiometric titra-tion

应用铂电汲电位滴定法测定了桔汁饮品中的抗坏血酸含量．样品用草酸溶液稀释，过滤后即可测定．由于本法以滴定终点前后的电位突跃变化来判定滴定终点，故无论样品有无颜色均可直接测定．本方法的回收率大于９７％，变异系数小于１．１％．

This paper describes the application of potentiometric titration with platinum elec-trode to the determination of the content of vitamin C in the citrus juice beverage. The sample were diluted with oxalic acid solution and were used for assay after filtering. Because the end point of titration was recognized by a sudden leap of the potential rather than the color change of the solu-tion, both the colorless and colored sample solutions could be determined directly. The recovery rate was greater than 97% with a coefficient of variation smaller than 1.1%.