核磁共振氢谱内标法测定常山碱的绝对含量

Quantitative determination of febrifugine by proton nuclear magnetic resonance spectroscopy with internal standard method

建立测定常山碱绝对含量的核磁共振氢谱定量分析方法。采用Bruker Ascend 600 MHz超导核磁共振仪,在298 K下,以氘代二甲基亚砜为溶剂,对苯二酚为内标,在频率600 MHz,谱宽7 211 Hz,脉冲宽度（P1）9.70μs,zg30脉冲序列,扫描次数（NS）32次,弛豫时间（Dl）2 s的条件下采集常山碱样品的氢谱。以化学位移在δ7.71的常山碱双峰和化学位移在δ6.55的对苯二酚的单峰作为定量峰,将样品与内标选定峰的峰面积比对其质量比回归得到标准曲线方程为Y=0.083 3X＋0.008 6,r为0.999 6。常山碱的线性范围为2.17-17.07 g·L^-1,精密度试验RSD为0.78%（n=6）,重复性试验RSD为1.2%（n=6）,测得3批常山碱样品量分别为94.91%,95.09%和95.52%。采用高效液相色谱法测得常山碱的含量为96.44%,二者的相对误差为1.27%。结果表明,核磁共振氢谱内标法可用于常山碱绝对含量的测定。

A quantitative nuclear magnetic resonance method（q NMR） was established for determination of the absolute content of febrifugine.Proton nuclear magnetic resonance spectroscopy of febrifugine was obtained in DMSO-d6 with hydroquinone as the internal standard substance on a Bruker Ascend 600 MHz superconducting nuclear resonance spectrometer at 298 K.The specific parameters were as follows：the observing frequency was 600 MHz,spectra width was 7 211 Hz,pulse width was 9.70 μs,pulse sequence was zg30,scan times was 32 and relaxation time was 2 s.The proton signal peaked at δ 7.71 for febrifugine and δ 6.55 for hydroquinone were selected as the quantification peaks.Linear regression of quantitative peak area ratio of febrifugine-hydroquinone versus their mass ratio yielded a correlation coefficient of 0.999 6 and a regression equation of Y=0.083 3 X＋0.008 6.The linear range of febrifugine was 2.17-17.07 g·L^-1,the precision RSD was 0.78%（n=6）,the repeatability RSD was 1.2%（n=6）,and the contents of three batches of febrifugine sample were 94.91%,95.09% and 95.52%,respectively.The content of febrifugine was 96.44% determined by high performance liquid chromatography（HPLC）.The relative error of the content of febrigugine determinted by q NMR and HPLC methods was 1.27%.The results showed that the internal standard method of proton nuclear magnetic resonance spectroscopy could be used to determine the absolute content of febrifugine.