过硫酸钾存在下吸附缔合/平行催化波法测定酮洛芬

Determination of Ketoprofen Using Its Adsorbed Association/Parallel Polarographic Catalytic Wave in the Presence of Persulfate

应用线性扫描极谱法和循环伏安法,在0.10 mol/L NH4C l-NH3.H2O（pH 9.5）-0.01 mol/L K2S2O8底液中,对酮洛芬（KPF）的电化学行为进行了研究。在该底液中KPF于峰电位-1.37 V（vs.SCE）处产生1个灵敏的吸附缔合/平行催化波。该极谱催化波中S2O82-有双重作用：①S2O82-作为配位体与吸附在电极表面的质子化KPF形成缔合物,引起峰电位负移;②S2O82-及其还原中间产物SO4-作为氧化KPF羰基经单电子单质子还原的自由基,产生了极谱催化,使峰电流显著增加。该极谱催化波的二阶导数峰峰电流与KPF浓度在1.97×10^-8~3.94×10^-6mol/L范围内呈线性关系,检出限为6.57×10^-9mol/L（3σ）。对3.94×10^-7mol/LKPF溶液进行13次平行测定,RSD为1.24%。该催化波的分析灵敏度比相应还原波提高20倍。该方法已用于药剂中KPF的测定。

The electrochemistry behavior of ketoprofen in 0.10 mol/L NH4Cl-NH3·H2O-0.01 mol/L K2S2O8 base solution at pH 9.5 was developed by linear scanning polarography and cyclic voltammetry.In the base solution,ketoprofen yielded a sensitive adsorbed association/parallel catalytic wave with the peak potential of the catalytic wave at-1.37 V（vs.SCE）.The catalytic wave showed the distinct characteristics such as the negative shift of the peak potential and the great increase of the peak current in ketoprofen-persulfate system.Persulfate as ligand formed an association complex with protonated ketoprofen adsorbed at electrode surface.Also persulfate and its reduction species as oxidants oxidized the carbonyl radical of ketoprofen which acted as catalyst involving in an 1e-/1H＋ reduction reaction.The 2nd-order derivative peak current of the catalytic wave varied linearly with the KPF concentration over the range from 1.97×10-8 to 3.94×10^-6 mol/L with detection limit of 6.57×10^-9 mol/L.RSD（n=13） was 1.24% at the concentration level of 3.94×10^-7 mol/L.The sensitivity of the catalytic wave of KPF was 20 times higher than that of the corresponding reduction wave.The proposed method has been applied to the determination of KPF in capsules with satisfactory results.