【摘要】 建立了一种快速、准确,溶剂消耗少的测定可乐饮料中咖啡因含量的紫外光谱分析方法,并将大相比离心萃取应用于仪器分析样品微制备过程。该方法将2mL三氯甲烷直接加入装有100μL可乐饮料的离心试管中,离心萃取3min后取清液在278nm处进行紫外光谱测定,操作简单、快速,重现性好,相对标准偏差小于3%;在3种可乐饮料中加入不同浓度的咖啡因标准溶液,回收率在96.6%～106.1%之间。线性范围为0.5～30mg/L,相关系数为0.9999;检出限为0.001mg/L。将本方法应用于市售可乐饮料中咖啡因含量分析,取得了满意的结果。更多还原

【Abstract】 A rapid,accurate and organic solvent saving method has been developed for the ultraviolet spectrophotometric(UV)determination of caffeine in beverages.The centrifugal extraction procedure with large phase ratio was applied to sample micropreparation prior to instrumental analysis.The method involves the mixing of 100 μL sample with 2 mL chloroform and a 3-min centrifugal extraction procedure in a centrifugal tube.The clear solution obtained was directly determined by UV detection at wavelength of 278 nm.The manipulation was simple and repeatable,and the relative standard deviation of the method was less than 3% for the independent measurement.When added different concentration of standard caffeine solution to three brand beverages,the recovery of the caffeine was in the range of 96.6%-106.1%.A linear calibration curve was obtained with caffeine concentration ranging from 0.50-30 mg/L,giving the correlation coefficient as 0.9999.The method provides a 0.001 mg/L detection limit of caffeine.The developed method was applied to determine the caffeine content in commercial beverages with good results.更多还原