Ordos Public Security Bureau, Ordos 017000, Inner Mongolia Autonomous Region, China.
Key Laboratory of Drug Monitoring and Control, Drug Intelligence and Forensic Center, the Ministry of Public Security of the People's Republic of China, Beijing 100193, China.
Fa Yi Xue Za Zhi. 2021 Feb;37(1):33-37. doi: 10.12116/j.issn.1004-5619.2019.390901.
Objective To establish an infrared spectroscopic method for the rapid qualitative and quantitative analysis of caffeine and sodium benzoate in Annaka samples. Methods Qualitative and quantitative modeling samples were prepared by mixing high-purity caffeine and sodium benzoate. The characteristic absorption peaks of caffeine and sodium benzoate in Annaka samples were determined by analyzing the infrared spectra of the mixed samples. The quantitative model of infrared spectra was established by partial least squares （PLS）. Results By analyzing the infrared spectra of 17 mixed samples of caffeine and sodium benzoate （the purity of caffeine ranges from 10% to 80%）, the characteristic absorption peaks for caffeine were determined to be 1 698, 1 650, 1 237, 972, 743, and 609 cm. The characteristic absorption peaks for sodium benzoate were 1 596, 1 548, 1 406, 845, 708 and 679 cm. When the detection of all characteristic absorption peaks was the positive identification criteria, the positive detection rate of caffeine and sodium benzoate in 48 seized Annaka samples was 100%. The linear range of PLS quantitative model for caffeine was 10%-80%, the coefficient of determination （ ） was 99.9%, the root mean square error of cross validation （RMSECV） was 0.68%, and the root mean square error of prediction （RMSEP） was 0.91%; the linear range of PLS quantitative model for sodium benzoate was 20%-90%, the was 99.9%, the RMSECV was 0.91% and the RMSEP was 1.11%. The results of paired sample t test showed that the differences between the results of high performance liquid chromatography method and infrared spectroscopy method had no statistical significance. The established infrared quantitative method was used to analyze 48 seized Annaka samples, the purity of caffeine was 27.6%-63.1%, and that of sodium benzoate was 36.9%-72.3%. Conclusion The rapid qualitative and quantitative analysis of caffeine and sodium benzoate in Annaka samples by infrared spectroscopy method could improve identification efficiency and reduce determination cost.
目的 建立一种快速定性定量分析安钠咖中咖啡因和苯甲酸钠的红外光谱法。方法 采用高纯度咖啡因和苯甲酸钠混合制备定性定量建模样品。通过分析混合样品的红外光谱，确定安钠咖样品中咖啡因和苯甲酸钠的特征吸收峰。采用偏最小二乘法（PLS）建立红外光谱定量模型。结果 通过分析 17 份不同纯度咖啡因（10%-80%）和苯甲酸钠混合样品的红外光谱，确定咖啡因的特征吸收峰为 1 698、1 650、1 237、972、743 和 609 cm；苯甲酸钠的特征吸收峰为 1 596、1 548、1 406、845、708 和 679 cm。当所有特征吸收峰均为阳性识别标准时，48 份缴获的安钠咖样品中咖啡因和苯甲酸钠的阳性检出率为 100%。咖啡因的 PLS 定量模型线性范围为 10%-80%，相关系数（ ）为 99.9%，交叉验证均方根误差（RMSECV）为 0.68%，预测均方根误差（RMSEP）为 0.91%；苯甲酸钠的 PLS 定量模型线性范围为 20%-90%， 为 99.9%，RMSECV 为 0.91%，RMSEP 为 1.11%。配对样本 t 检验结果表明，高效液相色谱法和红外光谱法的检测结果无统计学差异。采用建立的红外定量方法对 48 份缴获的安钠咖样品进行分析，咖啡因的纯度为 27.6%-63.1%，苯甲酸钠的纯度为 36.9%-72.3%。结论 红外光谱法可快速定性定量分析安钠咖中咖啡因和苯甲酸钠，提高鉴定效率，降低检测成本。
