邻菲口罗啉-Fe(Ⅱ)体系光度法间接测定头孢噻肟钠

Spectrophotometric indirect determination of cefotaxime by o-phenanthroline hydrate-Iron(Ⅱ)

基于头孢噻肟钠在0.3 mol/L NaOH溶液中沸水浴降解产物具有还原性,在酸性介质中可将Fe（Ⅲ）还原为Fe（Ⅱ）,邻菲啰啉能与所生成的Fe（Ⅱ）显色生成红色络合物,最大吸收波长λ=508 nm;表观摩尔吸光系数ε=1.1×10^4L.mol^-1.cm^-1;头孢噻肟钠在0.4～80μg/mL范围内呈良好的线性关系;线性回归方程为A=-0.00204＋0.01989ρ（μg/mL）;线性相关系数r=0.9998;检出限为0.18μg/mL;RSD为1.2%（5.0μg/mL,n=11）;平均回收率为99%。初步探讨了反应机理,并优化了对头孢噻肟钠的测定条件。

A simple and sensitive spectrophotometric method is described for the determination of cefotaxime. The method is based on the degradation of cefotaxime which was carried out in 0.3 mol/L NaOH solution at 100℃, and can be oxidized by Fe（Ⅲ） in acidic solution. Fe（Ⅱ ） can form a complex with o-phenanthroline hydrate, of which the maximum absorption wavelength is at 508nm, ε= 1.1×10^4 L（mol·cm）. The Beer＇s law is obeyed in the range of 0.4 ～ 80μg/mL for cefotaxime. The linear regression equation is A = - 0.00204 ＋ 0.01989C （μg/mL）, with a linear correlation coefficient of 0.9998. The detection limit is 0.18 μg/mL. RSD is 1.2% （5.0μg/mL, n = 11）, and average recovery is 99%. The reaction mechanism is studied intensively. This proposed method has been successfttlly applied to the determination of cefotaxime with satisfactory results.