液相色谱法测定茶氨酸提取物中咖啡因的含量

Determination of caffeine in theanine extract by high performance liquid chromatography

中文关键词:  高效液相色谱法  茶氨酸提取物  咖啡因

英文关键词:high performance liquid chromatography  theanine extracts  caffeine

中文摘要:

      目的 建立一种快速、简便测定茶氨酸提取物中咖啡因的液相色谱方法。方法 样品经过前处理, 以1-癸烷磺酸钠溶液(1.22 g→850 mL)+乙腈+磷酸=850+150+1(V:V:V)为流动相, 流速1.0 mL/min, 柱温40 ℃, 进样量10 μL, 等度洗脱, 经Agilent C18柱分离, 于280 nm波长处检测, 以外标法定量。结果 用本方法进行检测, 能很好的分离咖啡因, 在浓度0.001 mg/mL至0.05 mg/mL之间呈现良好的线性关系, 方法的相关系数可达1.000, 平均回收率为100.2, 在95%~105%之间, 相对标准偏差(RSD)为1.0%, 定量限为92.78 μg/g, 检出限为29.03 μg/g。结论 该方法耗时短、操作简便、准确、重现性好、分离效果明显。可以应用于茶氨酸提取物中咖啡因含量的测定。

英文摘要:

      Objective To establish a quick and simple method for the determination of caffeine in theanine extracts by high performance liquid chromatography (HPLC). Methods Samples were pretreated and were separated by agilent C18 column with gradient elution by a mobile phase of 1-decane sulfonic acid sodium solution(1.22 g→850 mL)-acetonitrile-phosphoric acid with 850+150+1(V:V:V), the flow rate at 1.0 mL/min, column temperature at 30 ℃, injection volume at 10 μL, and detected at 280 nm, then quantified by external standard method. Results Caffeine can be separated well and had a good linearity in the range of 0.001~0.05 mg/mL (r=1.000), the recovery was 95%~105%, and RSD was 1.0%; the limit of quantitation was 92.78 μg/g, and the limit of detection was 29.03 μg/g. Conclusion The method is quick, simple and accurate, and has a good reproducibility and clear separation. It can be applied for the determination of caffeine in tea theanine extracts.