氢核磁定量分析技术测定人参皂苷Rd对照品含量的研究

建立了氢核磁定量技术准确、快速测定人参皂苷Rd对照品含量的方法。考察了核磁共振实验条件对测定结果的影响。选择混合溶剂氘代DMSO d6∶D₂O（9∶1，V/V）为溶剂，苯甲酸为内标，观测频率400.13 MHz，脉冲延迟时间5 s，采样次数32 次，采集人参皂苷Rd和苯甲酸内标混合物的1H NMR谱图。定量峰为苯甲酸2位和6位质子信号δ 7.94，人参皂苷Rd 24位质子信号δ 5.07。结果表明，氢核磁定量测定的线性相关系数R = 0.997 8，精密度相对标准偏差为0.65%，回收率分别为98.69%～102.54%，相对标准偏差为1.92%，说明该方法准确性良好。实际测定3 批人参皂苷Rd的质量分数分别为98.87%，98.79%和98.92%。氢核磁定量技术测得对照品的质量分数略低于HPLC的面积归一化法。该方法无需待测物对照品，且对检测样品无破坏性、重现性好，可用于人参皂苷Rd对照品的含量测定和质量控制。

Quantitative 1H NMR based content determination of ginsenoside Rd

To establish an accurate and rapid method for content determination of ginsenoside Rd with quantitative ¹H NMR. Benzoic acid served as internal standard, DMSO-d6 and D₂O (9:1, V/V) as solution.¹H NMR spectra of the mixture of ginsenoside Rd and benzoic acid were acquired with spectrometer frequency 400.13 MHz scanning 32 times, relaxation delay time 4 s. Ginsenoside Rd proton peak at δ 5.07 and benzoic acid signal δ 7.94 served as quantification peaks. Linear regression equation of correlation coefficient of 0.997 8, RSD of precision were less than 0.65%, the average recoveries were in the range of 98.69% to 102.54% with RSD less than 1.92%. The contents of 3 batches of ginsenoside Rd were 98.87%, 98.79% and 98.92%. Experimental results show that the concentration of quantitative ¹H NMR determined ginsenoside Rd is slightly lower than that by HPLC without reference substance. The method is simple, accurate, and has good application value, can be used for the content determination and quality control of ginsenoside Rd.