离子色谱-直接电导法检测盐酸二甲双胍药物中二甲胺的残留

目的：建立离子色谱-直接电导法测定盐酸二甲双胍药物中二甲胺残留的方法。方法：盐酸二甲双胍药物用水溶解后直接进样，采用20 mmol·L^-1甲磺酸水溶液为淋洗液，以Dionex Ionpac CS12A（4 mm×250 mm）色谱柱进行分离，流速为1.0 mL·min^-1，CSRS 500-4 mm阳离子抑制器和电导检测器抑制并直接检测，抑制电流60 mA，柱温30℃，进样体积25 μL。结果：二甲胺在0.1~10.0 μg·mL^-1范围内线性关系良好（r=0.999 4），方法的检测限为0.032 8 μg·mL^-1（S/N=3），方法的定量下限为0.12 μg·mL^-1（S/N=10），平均回收率为97.6%~99.5%，RSD均不超过3%。结论：该方法操作简单、灵敏度高、重现性好，可用于盐酸二甲双胍药物中二甲胺残留的检测。

Objective: To establish an ion chromatography method for the determination of dimethylamine residues in metformin hydrochloride substances.Method: After dissolved by water, the sample solution was loaded onto the instrument.The determination was performed on a Dionex Ionpac CS12A(4 mm×250 mm) column.The eluent was 20 mmol·L^-1 methanesulfonic acid solution at a flow rate of 1.0 mL·min^-1.Dimethylamine was detected by suppressed conductivity with a CERS 500-4 mm suppressor at a current of 60 mA, the column temperature was 30℃ and the injection volume was 25 μL.Results: The calibration curves showed good linearity in the range of 0.1-10.0 μg·mL^-1(r=0.999 4);the limit of detection(LOD) of the method was 0.0328 μg·mL^-1(S/N=3) and the limit of quantification(LOQ) of the method was 0.12 μg·mL^-1(S/N=10).The recovery of dimethylamine ranged from 97.6% to 99.5% with RSD not more than 3%。Conclusion: The method has the advantages of simple operation, high sensitivity, good reproducibility, and can be used for the detection of dimethylamine in metformin hydrochloride substances.