钼蓝比色法测定甜樱桃中还原型VC含量的条件优化

Optimizing the Determination of the Content of Reduction-type Vitamin C in Sweet Cherry

采用钼蓝比色法测定甜樱桃中还原型VC含量,探讨了此方法的最佳测定条件。结果表明,钼蓝比色法的最大吸收峰为850 nm,5%硫酸溶液和5%钼酸铵溶液的最佳用量分别为1.50 m L和3.00 m L,最适反应时间为14 min,在此条件下测得R2为0.998 7。优化后的测定方法变异系数小于5%,平均回收率为98.52%,还原型VC含量在0.00-0.12 mg/50 m L内呈良好的线性关系。该方法准确、快速、稳定,适合少量和批量样品的测定。用此法测得天水甜樱桃样品中的还原型VC的平均含量为2.032 mg/100 g。

Molybdenum blue spectrometry method was used to determine reduced vitamin C in sweet cherry and conditions of determination were optimized. The results showed that there was a strong absorption at 850 nm. The dosage of 5% sulfuricacid solution,5% molybdate-ammonium solution in reaction system were 1.50 m L and 3.00 m L respectively. The optimal reaction time was 14 min. The coefficient of variation of the optimized method was less than 5 %, with the average recovery of98.52%. The method had a good linear relationship in the course of 0.00-0.12 mg/50 m L. The method was accurate, rapid,stable and suitable for determining small-amount and batch samples. The average content of reduction-type vitamin C in sweet cherry of Tianshui was 2.032 mg/100 g.