表面活性剂增敏硝普钠分光光度法测定甲硝唑

Spectrophotometric determination of metronidazole with sodium nitroprusside based on the sensitization effect of surfactant

本文建立了十四烷基二甲基苄基铵增敏作用下硝普钠分光光度法测定甲硝唑的方法。研究表明：在碱性条件下,甲硝唑与硝普钠反应生成化学计量比为1∶1的红褐色产物,其最大吸收波长λmax=500 nm,表观摩尔吸光系数为ε=9.8×103L.mol-1.cm-1。甲硝唑在0.70~30μg.mL-1浓度范围内与吸光度成良好线性关系,线性回归方程为A=-0.031＋0.057C（μg.mL-1）,线性相关系数r=0.9994,RSD为0.34%,检测限（3σ/k）为0.61μg.mL-1。本方法可用于甲硝唑注射液含量的测定,回收率为99.0~102.0%。

A novel spectrophotometry for the determination of metronidazole was developed.The method is based on the reaction between metronidazole and sodium nitroprusside with the sensitization effect of tetradecyl benzyl dimethyl ammonium chloride in basic medium.The reaction stoichiometric ratio is 1∶1 and a russety product is formed with the maximum absorption wavelength at 500 nm.The apparent molar absorption coefficient（ε500）is 9.8×103 L·mol-1·cm-1.A good linear relationship between the concentration of metronidazole and the absorbance is in the range of 0.70-30 μg·mL-1 and the liner regression equation is A=-0.031＋0.057C（μg·mL-1）with a correlation coefficient r=0.9994.The relative standard deviation（RSD）and the limit of detection（3σ/k）are 0.34% and 0.61μg·mL-1,respectively.The proposed method has been applied to the determination of metronidazole in parenteral solution with the recoveries of 99.1%-102%.