用铁氰化钾分光光度法测定头孢噻肟钠

建立了以铁氰化钾测定头孢噻肟钠的分光光度法。 在0.20 mol/L NaOH溶液中，头孢噻肟钠(CTX)于100 ℃水浴中降解生成的巯基化合物能将Fe(Ⅲ)(pH=3.0)还原为Fe(Ⅱ)，根据Fe(Ⅱ)与K3[Fe(CN)6]反应生成可溶性普鲁士蓝(KFeⅢ[FeⅡ(CN)6])的吸光度，可以间接测定头孢噻肟钠的含量。 头孢噻肟钠在0.040~24 mg/L范围内与吸光度(A)呈线性关系，线性回归方程:A=0.05088+0.2166ρ(mg/L)，相关系数R=0.9986，检出限为0.01 mg/L，相对标准偏差(RSD)为1.36%(n=11)，表观摩尔吸光系数ε=2.3×105 L/(mol·cm)。 此方法可用于药物及血清中头孢噻肟钠含量的测定。

Spectrophotometric Determination of Cefotaxime Sodium with Potassium Ferricyanide

A spectrophotometric method has been set up to determine cefotaxime sodium using potassium ferricyanide as the spectroscopic probe reagent. With the presence of potassium ferricyanide, the degradation product of cefotaxime sodium can reduce Fe3+ to Fe2+ at pH 3.0, which facilitate the formation of soluble Prussian Blue (KFeⅢ[FeⅡ(CN)6]). The absorbance of soluble Prussian Blue is measured at its absorption maximum of 730 nm and the amount of cefotaxime sodium can be indirectly calculated. Under optimized conditions, a good linear relationship is obtained in the range of 0.040~24 mg/L of cefotaxime sodium. The linear regression equation is A=0.05088+0.2166ρ(mg/L) with linear correlation coefficient of 0.9986. The detection limit and relative standard deviation are 0.01 mg/L and 1.36%, respectively. Tthe apparent molar absorption coefficient of indirect determination of cefotaxime sodium is 2.3×105 L/(mol·cm). This method has been successfully applied to the determination of cefotaxime sodium in pharmaceutical and serum samples.