荷移荧光光谱法测定牛奶中苄青霉素残留

Fluorescence spectrometric determination of benzylpenicillin residues in milk by charge-transfer reaction

采用荧光光谱法研究了电子供体苄青霉素降解产物与电子受体四氯苯醌(TCBQ)之间的荷移反应,结果表明TCBQ与苄青霉素的酸性降解产物在甲醇-水介质中易发生荷移反应,生成稳定的络合物,其荧光强度较苄青霉素降解产物本身有了显著的增强。据此建立一种测定苄青霉素的新方法,在最佳条件下,苄青霉素浓度在0.30～8.0 mg/L范围内与荧光强度呈良好的线性关系,检出限为0.09 mg/L。同时研究了荷移络合物的红外光谱,探讨了荷移反应的机理。利用该方法对牛奶中苄青霉素含量进行了测定,并进行了加标回收试验,回收率为88.0%～95.4%,相对标准偏差为1.3%～1.5%。

The charge-transfer reaction of benzylpenicillin degradation droduct as the donor with 2,3,5,6-tetrachloro-1,4-benzoquinone（TCBQ） as the acceptor was investigated by fluorimetry.The results showed that TCBQ was prone to react with acidic degradation products of benzylpenicillin to producea stable charge-transfer complex in a mixture of methanol and water.Fluorescence intensity of the complex was increased significantly relative to benzylpenicillin degradation product.Therefore a new method for the determination of benzylpenicillin has been developed.A linear calibration graph was obtained over the benzylpenicillin concentration ranging from 0.30~8.0 mg/L with a detection limit of 0.09 mg/L under optimal conditions.Furthermore,infrared spectroscopy of the charge-transfer complex was studied and the mechanism of charge-transfer reaction was explored.The method has been applied to the determination of benzylpenicillin in milk and spike recovery tests were carried out.The recoveries were 88.0%~95.4%,and the relative standard deviations are 1.3%~1.5%.