核磁共振定量法测定脒基吡唑含量

目的： 建立核磁共振定量法（qNMR法）测定脒基吡唑盐酸盐中脒基吡唑含量。 方法： 以对苯二酚为内标，氘代甲醇为溶剂测定¹H核磁共振谱，通过比较样品定量峰与内标物质响应峰峰面积，计算脒基吡唑的含量。 结果： 同一样品在相同条件下测定6次，定量峰与内标响应峰比值的RSD为0.38%；平行配制5份样品溶液，定量峰与内标响应峰比值的RSD为0.29%。采用不同样品定量峰计算的脒基吡唑含量分别65.6%、65.8%、66.3%，RSD分别为0.71%、0.97%、1.4%，与质量平衡法测定结果65.7%接近。 结论： 本文建立的qNMR法可以有效避免盐酸干扰，经方法验证可用于测定脒基吡唑含量。

Objective: To establish a quantitative NMR(qNMR)method to determine the content of 1H-pyrazole-1-carboxamidine in 1H-pyrazole-1-carboxamidine hydrochloride. Methods: Hydroquinone was used as an internal standard,methanol-d₄ as solvent in ¹H-NMR to characterize 1H-pyrazole-1-carboxamidine,and calculate the content of 1H-pyrazole-1-carboxamidine by comparing the response peak area of sample(A_s)and internal standard(A_r). Results: One sample solution was characterized under the same NMR conditions for six times,RSD of A_s/A_r was 0.38.For five sample solutions which were parallel prepared,RSD of A_s/A_r was 0.29%.Meanwhile,based on different peaks,the content of 1H-pyrazole-1-carboxamidine calculated was 65.6%,65.8% and 66.3% respectively,RSD was 0.71%,0.97% and 1.4% respectively.The results were consistent with the result from mass balance method(65.7%). Conclusion: Using qNMR to characterize the content of 1H-pyrazole-1-carboxamidine can avoid the effect of hydrochloride.This method can be used for determination of the content of 1H-pyrazole-1-carboxamidine according to the method validation.

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