抗坏血酸棕榈酸酯测定方法的比较

将改进滴定碘法应用于抗坏血酸棕榈酸酯含量的测定,并与碘滴定法和硅钼兰分光光度法进行了比较。结果表明,几种常用方法的测定结果略有差异,《食品添加剂手册》中的碘滴定法由于溶液混浊影响终点判断,导致结果偏高,重现性较差;硅钼兰分光光度法灵敏度较高,但需要试剂多,测定周期长;滴定碘法与GB 16314-1996中方法的测定结果在5%水平上无显著差异,但由于滴定碘法中淀粉指示剂变色更明显,易于判断滴定终点,方法的精密度更高,且简单快速,可用于抗坏血酸棕榈酸酯含量的日常检测。

Comparison of the determination methods of ascorbyl palmitate

The ascorbyl palmitate was determined by the improved iodimetry and compared with iodimetry and silicon molybdenum blue spectrophotometer method. The results showed that there were slight differences among the results determined by the common methods. The result by the iodimetry according to Food Additive Manual was leaning high and poor repeatability because of the turbid solution; the result by silicon molybdenum blue spectrophotometer method has a higher sensitivity, but needs more reagents and longer determination period. No significant difference between the results in GB 16314-1996 and iodometry at 5% level. The improved iodometry was easier to judge the end point of titration and had a higher precision, since the color change of the starch indicator was more obvious. This method is easy and quick, and can be used for the daily determination of the ascorbyl palmitate.