可乐型饮料中咖啡因的测定

Determination of Caffeine in cola-type Beverages

目的探讨可乐型饮料中咖啡因含量的检测方法。方法用三氯甲烷提取样品中的咖啡因后,在276.5 nm波长下测其吸光度值,与标准系列比较定量,测定可乐型饮料中咖啡因的含量。结果紫外分光光度法的回收率为96.3%~105.9%,变异系数为3.2%,萃取温度以20~40℃为宜,最大吸收峰在276.5 nm处。结论紫外分光光度法测定可乐型饮料中咖啡因的含量,简单迅速,适合一般实验室应用。

[Objective]To explore the measurement of caffeine content in cola-type beverages.[Methods]After extraction from samples by chloroform,the absorbance value of caffeine was measured under 276.5 nm wavelength,then comparing with the standard series,the content of caffeine was determined in cola-type beverages.[Results]The recovery of UV spectrophotometry was 97.5%,coefficient of variation was 3.2%,the appropriate extraction temperature was 20~40 ℃,the maximum absorption wavelength of caffeine was 276.5 nm.[Conclusion]The UV spectrophotometry method is simple and rapid in determining caffeine content of cola-type beverages,meeting the needs of general laboratory.