在pH 7.53的Tris-盐酸缓冲溶液中,溴百里酚蓝与甲砜霉素反应生成稳定缔合物,导致显色剂溴百里酚蓝吸光度降低,据此建立了褪色分光光度法测定甲砜霉素的含量。在波长604 nm处测定,甲砜霉素的质量浓度在5.3 mg·L-1以内与反应体系吸光度的降低呈线性关系,表观摩尔吸光率为3.12×104L·mol-1·cm-1。方法用于市售甲砜霉素药物中甲砜霉素的测定,测定值与标示量相符。用标准加入法以人尿样品作基体,测得方法的回收率在98.3%~102%之间。

A stable association complex was formed by the reaction of thiamphenicol with bromothymol blue in Tris-HCl buffer solution of pH 7. 53, leading to decrease of absorption of bromothymol blue. Linear relationship between the magnitude of decrease in absorbance at 604 nm and the mass concentration of thiamphenicol was obtained in the range within 5.3 mg·L-1, and value of apparent molar absorptivity found was 3.12×104L·mol-1·cm-1. The proposed method was used in the determination of thiamphenicol in samples of commodity thiamphenicol medicine, the results obtained was checked quite well with the labelled values, and values of recovery found by standard addition method using human urine sample as matrix were in the range of 98.3%-102%.