极谱催化波法测定地塞米松

Determination of Dexamethasone Using Its Polarographic Catalytic Wave

基于地塞米松在过硫酸钾存在下产生的极谱催化波 ,拟定了测定地塞米松的新方法。与基于还原波的差分脉冲极谱法相比 ,本方法用线性变位极谱法获得的分析灵敏度提高了两个数量级。在 2 .0× 10 - 3mol LH2 SO4 ～ 2 .0× 10 - 2 mol LK2 S2 O8底液中 ,地塞米松于 - 1 0 8V (vs .SCE)处产生一极谱催化波 ,其二阶导数峰电流与地塞米松浓度在 3.2× 10 - 8～ 3.2× 10 - 7mol L范围内呈线性关系 (r =0 .9994 ,n =6 ) ,检出限为 1.0×10 - 8mol L。讨论了极谱催化波产生的机理。

A Method for the determination of dexamethasone is proposed based on its polarographic catalytic wave in the presence of K2S2O8. As compared with the polarographic methods on basis of the reduction wave with differential pulse polarography, the proposed method by linear-potential scan polarography improved nearly two orders in magnitude in analytical sensitivity. In 2.0 x 10(-3) mol/L H2SO4-2.0 x 10(-2) mol/L K2S2O8 supporting electrolyte, the dexamethasone yields a polarographic catalytic wave with the potential - 1.08 V. The second-order derivative peak current of the catalytic wave is rectilinear to dexamethasone concentration in the range of 3.2 x 10(-8) - 3.2 x 10(-7) mol/L ( r = 0.9994, n = 6). The limit of detection is 1.0 x 10(-8) mol/L. The mechanism of the polarographic catalytic wave of dexamethasone is discussed.