固定pH滴定法与高效液相色谱法测定乙酰氧肟酸含量的有效性比较

Comparison of determination effectiveness of acetohydroxamic acid by fixed pH titration method and HPLC

建立了pH滴定法与高效液相色谱法（HPLC）测定极弱酸药物中间体乙酰氧肟酸（AHA）含量，并比较2种方法的有效性。固定pH滴定法用NaOH溶液为滴定剂，在空白溶液中加入不同量的AHA后进行滴定，得出固定pH，并在固定pH处进行检测。结果表明，固定pH法在pH为12时消耗NaOH溶液的体积对AHA含量具有很好的线性关系（R2=0．9999）；高效液相色谱法在AHA质量浓度为100～1000mg／L的范围内线性关系良好（R2=0．9999），平均回收率为100．3％，RSD为1．77％（n=9）。2种方法的检测结果相对误差在0．2％左右，均对AHA的检测有较高有效性。本研究对极弱酸性与极弱碱性药物中间体的纯度检测提供了方法依据。

The content of acetohydroxamic acid （ AHA ）, a pharmaceutical intermediate with very weak acidity, is determined by fixed pH titration and High Performance Liquid Chromatography （HPLC）. The effectiveness of two methods is compared as well. The results show that for fixed pH titration method, using NaOH as titrant and keeping pH at 12, the good linear relationship between volume of NaOH and content of AHA （R2 = 0. 999 9） can be obtained. For HPLC, the good linear relationship can be achieved when the content of AHA is in the range of 100 - 1 000 mg/L （R： = 0. 999 9）. The average recovery rates for two methods are both 100. 3% with RSD of 1.77% （ n = 9 ） , both of which exhibit good effectiveness for detection of AHA. It provides a promising approach for determining the pharmaceutical intermediate with very weak acidity or basicity.