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本文在碱性下用三氯甲烷抽提可乐型饮料中咖啡因的条件下,研究了样品中焦糖色成分对普通分光光度法测定咖啡因的干扰情况,采用二阶导数光谱分光光度法测量咖啡因274.5nm特征吸收峰,有效地消除了干扰。咖啡酊和可可酊中的咖啡因也具有相同的特征吸收峰。样品中啡咖因的最低检出限为0.4μg/ml,测定结果与薄层层折法的结果一致,不出现假阳性。方法的回收率为101.3±4.43％。
In this paper, under the condition of extracting caffeine from cola beverage with chloroform under alkaline condition, the interference of caramel color components in the sample to the determination of caffeine by common spectrophotometry was studied. The second derivative spectrophotometry was used to measure the coffee Due to the 274.5nm characteristic absorption peak, interference is effectively eliminated. Caffeine in coffee tinctures and cocoa tinctures also have the same characteristic absorption peaks. The minimum detectable limit of caffeine in the sample is 0.4μg / ml. The determination result is consistent with the result of the TLC, and no false positive occurs. The recovery rate of the method was 101.3 ± 4.43%.