贵州不同产地石韦中咖啡因的含量测定及提取工艺研究

A Study on Content Determination and Extraction Technology of Caffeine in Shiwei from Different Producing areas in Guizhou

目的:建立贵州不同产地石韦中咖啡因的HPLC含量测定的方法以分析不同批次的咖啡因的含量差异;探究石韦中咖啡因的提取工艺。方法:采用Wondasil C18(5μm, 250 mm×4.6 mm)色谱柱测定咖啡因含量,进行梯度洗脱,以流动相为乙腈(A)-0.2%磷酸水(B),柱温为25℃,检测波长为274 nm,流速为0.8 mL/min。以咖啡因的含量为指标,在单因素考察的基础上确定其最佳提取工艺。结果:在上述色谱条件下,咖啡因在10.58~211.60μL(r=0.999 5)范围内线性关系良好,平均加样回收率为97.32%,RSD=2.1%(N=6);通过分析发现,贵州不同产地石韦中的咖啡因含量存在显著性差异。进一步实验表明,最佳提取工艺条件为精密称定石韦粉末1.00 g,加入20 mL 50%甲醇,超声提取50 min。结论:所建立的测定方法可靠易行、准确性高、重复性好,可用于石韦中咖啡因的含量测定,为控制其利尿活性的质量提供参考。

Objective: To establish an HPLC method for the determination of caffeine in Shiwei from different producing areas in Guizhou Province to analyze the content difference of caffeine in different batches. To study the extraction technology of caffeine in Shiwei. Methods: The caffeine content was determined by Wondasil C18(5 μm, 250 mm*4.6 mm) chromatographic column with gradient elution. The mobile phase was acetonitrile(A)-0.2% phosphoric acid water(B). The column temperature was 25 °C, the detection wavelength was 274 nm, and the flow rate was 0.8 mL/min. Taking the caffeine content as an indicator, on the basis of single factor investigation, the optimal extraction process was determined. Results: Under the above chromatographic conditions, caffeine had a good linear relationship in the range of 10.58~211.60 μL(r=0.999 5), with an average recovery of 97.32%,RSD=2.1%(N=6). Through analysis, it was found that there were significant differences in the caffeine content in Shiwei from different producing areas in Guizhou. Further experiments showed that the optimal extraction conditions were as follows: accurately weighing 1.00 g of Shiwei powder produced in Guizhou, adding 20 mL of 50% methanol, and ultrasonically extracting for 50 min. Conclusion: The established method is reliable, accurate and reproducible, and can be used for the determination of caffeine content in Shiwei, which provides a reference for the quality control of its diuretic activity.