苯酚-硫酸法与蒽酮-硫酸法测定绿茶茶多糖的比较研究

对苯酚-硫酸法和蒽酮-硫酸法在茶多糖测定中的差异进行比较,并对苯酚-硫酸法的检测条件进行优化,在单因素试验的基础上,选定苯酚质量分数、硫酸用量、显色时间3个因素,利用响应面试验考察各因素变化对吸光度的影响。通过优化得到最佳测定条件为4.8%苯酚溶液1 mL、浓硫酸5 mL、显色时间29 min、检测波长488 nm。在此条件下的标准曲线在0~0.2 mg/mL范围内呈良好线性关系。该方法对3种样品的加标回收率均不小于97.55%,重复性实验相对标准偏差为1.82%,说明此方法准确可靠、稳定性高,适合于茶多糖的测定。

Comparison of Phenol-Sulfuric Acid and Anthrone-Sulfuric Methods for Determination of Polysaccharide in Green Tea

This study aimed to establish a phenol-sulfuric acid method for the determination of the polysaccharide content
in green tea and evaluate its performance in comparison with that of the anthrone-sulfuric method. In the phenol-sulfuric
acid method, three experimental conditions including phenol concentration, sulfuric acid dosage and color development time
were optimized by single factor experiments and response surface methodology using absorbance value as the dependent
variable. A mathematical regression model was established. The optimum experimental conditions were found as followes:
1 mL of 4.8% aqueous phenol solution, 5 mL of concentrated sulfuric acid, and detection at 488 nm after 29 min of color
development. There was a good linear relationship between absorbance and concentration in the range from 0 to 0.2 mg/mL.
The experimental results showed that the average recovery rate was equal to or higher than 97.55% with good reproducibility
(RSD = 1.82%, n = 7). The phenol-sulfuric acid method was rapid, accurate, sensitive and suitable for the determination of
polysaccharide in green tea.