试验表明:在pH 3.8的乙酸盐缓冲介质中,克林霉素磷酸酯(CLP)能将铁(Ⅲ)还原为铁(Ⅱ),而所生成的铁(Ⅱ)与邻菲啰啉反应生成有色络合物(λmax=508 nm),且生成的铁(Ⅱ)量与CLP之间存在定量关系,经换算所测得吸光度与CLP的质量浓度在0.70~140 mg·L-1之间呈线性关系。据此并结合流动注射技术(FI)提出了FI-分光光度法间接测定药物中CLP的新方法优化的分析条件如下:① 乙酸盐缓冲溶液的加入量:2.5 mL;② 铁(Ⅲ)溶液质量浓度:10.0 mg·L-1;③ 邻菲啰啉溶液浓度:1.5×10-3mol·L-1;④ 反应温度:85 ℃。该方法的检出限为0.060 mg·L-1。应用此方法测定了药物中CLP的含量,测定值与国家药品标准方法的测定值相符。

It was found that in an acetate buffer medium of pH 3.8, Fe(Ⅲ) ion was reduced to Fe(Ⅱ) ion by clindamycin phosphate (CLP) which in turn reacted with o-phenanthroline solution to form a colored complex (λmax=508 nm) and that linear relationship was kept between values of absorbance and mass concentration of CLP ［calculated indirectly from the amount of Fe(Ⅱ) ion found］ in the range of 0.70-140 mg·L-1. Based on this fact and by applying the FIA technique, an indirect FI-spectrophotometric method for determination of CLP was proposed. The optimum analytical conditions found were as follows: ① amount of the acetate buffer solution added: 2.5 mL; ② mass concentration of Fe(Ⅲ) solution: 10.0 mg·L-1; ③ concentration of o-phenanthroline solution: 1.5×10-3mol·L-1; ④ temperature of reaction: 85 ℃. Detection limit (3s/k) of the method found was 0.060 mg·L-1. The proposed method was applied to determination of CLP in drug samples, giving results in consistency with those found by the method of national standard of drugs.