State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, China.
Food Chem. 2013 Dec 15;141(4):4087-93. doi: 10.1016/j.foodchem.2013.06.121. Epub 2013 Jul 4.
A novel kinetic spectrophotometric method was developed for the simultaneous determination of caffeine, theobromine and theophylline in food samples. This method was based on the different kinetic characteristics between the reactions of analytes with cerium sulphate in sulphuric acid and the associated change in absorbance at 320 nm. Experimental conditions, the effects of sulphuric acid, cerium sulphate and temperature, were optimised. Linear ranges (0.4-8.4 μg mL(-1)) for all three analytes were established, and the limits of detection were: 0.30 μg mL(-1) (caffeine), 0.33 μg mL(-1) (theobromine) and 0.16 μg mL(-1) (theophylline). The recorded data were processed by partial least squares and artificial neural network, and the developed mathematical models were then used for prediction. The proposed, novel method was applied to determine the analytes in commercial food samples, and there were no significant differences between the results from the proposed method and those obtained by high-performance liquid chromatography.
建立了一种测定食品中咖啡因、可可碱和茶碱的动力学分光光度新方法。该法基于样品中咖啡因、可可碱和茶碱与硫酸铈在硫酸介质中反应的动力学特性不同，以及在 320nm 处吸光度的变化。实验优化了硫酸、硫酸铈用量和温度等实验条件。该方法对三种分析物的线性范围分别为 0.4-8.4μgmL(-1)，检出限分别为：0.30μgmL(-1)（咖啡因）、0.33μgmL(-1)（可可碱）和 0.16μgmL(-1)（茶碱）。记录的数据通过偏最小二乘法和人工神经网络进行处理，然后用所建立的数学模型进行预测。该新方法用于测定商业食品样品中的分析物，其结果与高效液相色谱法无显著差异。
