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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)2s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批常山碱样品的含量分别为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。
To establish a method for the quantitative analysis of abscisic acid by 1H-NMR. Using a Bruker Ascend 600 MHz superconducting nuclear magnetic resonance instrument, deuterated dimethyl sulfoxide as solvent and hydroquinone as an internal standard at 298 K, with a spectral width of 7 211 Hz and a pulse width (P1 ) 9.70μs, zg30 pulse sequence, the number of times of scanning (NS) 32 times, relaxation time (Dl) With the chemical shift in the δ7.71 bimodal peak and the chemical shift of δ5.65 in the hydroquinone single peak as a quantitative peak, the sample and internal standard peak area ratio of the mass ratio of the standard regression The curve equation is Y = 0.083 3X + 0.008 6, r is 0.999 6. The linear range of Changshan alkali was 2.17-17.07 g · L-1, the RSD of precision test was 0.78% (n = 6), RSD of repeatability test was 1.2% (n = 6) Respectively 94.91%, 95.09% and 95.52%. The content of Changshan base measured by HPLC was 96.44%, the relative error between the two was 1.27%. The results show that the internal standard method of 1H NMR can be used for the determination of the content of Changshan alkali.