果蔬Vc紫外分光光度直接测定法的改进

Improvement of Vc UV spectrophotometric direct determination in fruits and vegetables

VC是人体所必需的维生素之一,在体内不能合成,需通过膳食补充,广泛分布于新鲜的蔬果之中,同时也是评价蔬果品质的重要指标之一。Vc在紫外光区具有光吸收,在碱性环境中极不稳定易被降解。根据这些特性,实验在浸提液、测定条件和测定程序等方面对已有的紫外分光光度法进行了改进。改进后的方法,Vc质量浓度在0.5～20.0μg/mL范围内与紫外光吸收值呈良好的线性关系,方法检出限为0.0336μg/mL,加标回收率为(99.33±0.49)%。检测结果与荧光法一致。与现有方法比较,本方法快速、稳定、准确、试剂易得、灵敏度高,检测范围广,特别适用于Vc的高通量测定。

Vc is a kind of necessary vitamin for human health but cannot be synthesized in human body. Therefore, Vc must be supplemented through daily diet. Fresh fruits and vegetables are main resources of Vc. The content of Vc in fresh fruits and vegetables is thus used as an important indicator for quality evaluation. Here, an improved UV spectrophotometry method is reported for fast and accurate measurement of Vc in fresh fruits and vegetabJes. By adoption of the new method, the concentration of Vc has favorable linear relationship with the value of UV absorption when the concentration is between 0.5 μg/mL and 20.0 μg/mL. The detection limit is 0.0336 μg/mL, and the recovery ratios are （99.33±0.49）%. The results of fresh fruit tests showed good consistence with that of fluorescence method. Compared with the present methods, the new measurement has the merits of rapidity, stability, high sensitivity and wide detection range, and is especially suitable for high-throughput determination of Vc.