pH对高效液相色谱法测定保健食品中维生素B12含量结果的影响

Effect of pH on the determination results of vitamin B12 in health food by high performance liquid chromatography

中文关键词:  pH  维生素B12  保健食品  高效液相色谱法  碳酸钙

英文关键词:pH  vitamin B12  health food  high performance liquid chromatography  calcium carbonate

中文摘要:

      目的 研究不同pH条件对高效液相色谱法检测保健食品中维生素B12 检测结果差异性的影响。方法 选取原料中添加较高含量碳酸钙且样品溶液pH>7.0的复合维生素片, 调节样品溶液pH为4.0~4.5、5.0~5.5、6.0~6.5, 采用高效液相色谱法测定样品中维生素B12的含量并记录; 检测并记录用pH分别为4.02、5.01、6.05的水稀释得到的标准中间液维生素B12的检测结果; 记录并分析pH为4.0~4.5、5.0~5.5、6.0~6.5的样品和碳酸钙溶液60 min内pH的变化。结果 不同pH样品溶液维生素B12测得的结果值有显著性差异, 调节pH为4.20~4.50时测得的结果值与样品实际结果值相符; 维生素B12标准中间液在不同pH下测得的检测结果相同。样品和碳酸钙溶液的pH在60 min内随着时间的变化发生改变, 调节溶液pH>5.0时, 溶液的酸碱性较不稳定, 在10~20 min内溶液会由酸性变为碱性; 调节溶液pH<5.0时, 溶液在60 min内较稳定始终为酸性, 碳酸钙溶液的酸碱性与样品溶液有相同的变化趋势。结论 在保健食品维生素B12的检测中需要关注样品中原辅料的种类和配比对样品溶液检测过程中酸碱性的影响, 对原料中含较高含量碳酸钙且样品溶液pH>7.0的样品, 在检测维生素B12时需用柠檬酸调节溶液pH为4.2~5.0。

英文摘要:

      Objective To study the effect of different pH conditions on the difference of detection results of vitamin B12 in health food by high performance liquid chromatography (HPLC). Methods The compound vitamin tablets with high content of calcium carbonate and pH>7.0 were selected and adjusted to pH4.0?4.5, 5.0?5.5 and 6.0?6.5. The content of vitamin B12 in the sample was determined and recorded by HPLC. The detection results of vitamin B12 in the standard intermediate solution diluted with water with pH of 4.02, 5.01 and 6.05 were detected and recorded; the pH changes of samples with pH of 4.0?4.5, 5.0?5.5, 6.0?6.5 and calcium carbonate solution within 60 min were recorded and analyzed. Results There were significant differences in the results of vitamin B12 in different pH samples. When the pH was adjusted from 4.20 to 4.50, the measured results were consistent with the actual values of samples; the detection results of vitamin B12 standard intermediate solution at different pH were the same. The pH of the sample and calcium carbonate solution changed with time within 60 min. When the pH of the solution was adjusted to be more than 5.0, the pH of the solution was unstable, and the solution changed from acidic to alkaline within 10?20 min; when the pH of the adjusted solution was less than 5.0, the solution was stable and always acidic within 60 min, and the pH of calcium carbonate solution had the same change trend as the sample solution. Conclusion In the detection of vitamin B12 in health foods, it is necessary to pay attention to the influence of the type and ratio of raw materials and excipients on the acidity and alkalinity of the sample solution. For the samples with high content of calcium carbonate and pH>7.0, citric acid should be used to adjust the pH of the solution to 4.2?5.0.