Lauback R G, Balitz D F, Mays D L
J Chromatogr Sci. 1976 May;14(5):240-5. doi: 10.1093/chromsci/14.5.240.
An improved gas chromatographic method is described for the simultaneous determination of carboxylic acid chlorides and related carboxylic acids used in the production of some commercial semisynthetic penicillins. The acid chloride reacts with diethylamine to form the corresponding diethylamide. Carboxylic acid impurities are converted to trimethylsilyl esters. The two derivatives are separated and quantitated in the same chromatographic run. This method, an extension of the earlier procedure of Hishta and Bomstein (1), has been applied to the acid chlorides used to make oxacillin, cloxacillin, dicloxacillin, and methicillin (Figure 1); it shows promise of application to other acid chlorides. The determination is more selective than the usual titration methods, which do not differentiate among acids with similar pK's. Relative standard deviations of the acid chloride determination are 1.0-2.5%. Residual carboxylic acid can be repetitively determined within a range of 0.6% absolute.
本文描述了一种改进的气相色谱法，用于同时测定某些商业半合成青霉素生产中使用的羧酸氯化物和相关羧酸。酰氯与二乙胺反应形成相应的二乙酰胺。羧酸杂质被转化为三甲基硅酯。这两种衍生物在同一色谱运行中进行分离和定量。该方法是对希什塔和博姆斯坦早期方法（1）的扩展，已应用于制备苯唑西林、氯唑西林、双氯西林和甲氧西林所用的酰氯（图1）；它有望应用于其他酰氯。该测定方法比通常的滴定法更具选择性，后者无法区分具有相似pK值的酸。酰氯测定的相对标准偏差为1.0 - 2.5%。残留羧酸可在绝对误差0.6%的范围内重复测定。
