抗痫灵的电化学行为及吸附伏安法研究

抗痫灵在0.20 mol/L H₂SO₄底液、富集电位-0.70 V(vs Ag/AgCl)、扫速100 mV/s等条件下,用吸附伏安法得一灵敏的还原峰,峰电位-0.94 V,峰电流与抗痫灵浓度在3.0×10^-9～1.0×10^-8mol/L(富集时间t_ac=120 s),1.0×10^-8～7.0×10^-8mol/L(t_ac=90 s),7.0×10^-8～7.0×10^-7mol/L(t_ac=60 s),7.0×10^-7～3.0×10^-6mol/L(t_ac=45 s)范围内成线性关系,检测限可达1.0×10^-9mol/L,并用于片剂及病人尿样的测定,得到满意的结果。以多种电化学手段研究抗痫灵的电化学行为及反应机理。实验表明属不可逆吸附波。测得扩散系数D为7.7×10^-6cm²/s,电极反应速率常数k₁为1.5×10^-3cm/s,电极反应电子数n为2,电子转移系数α=0.52。抗痫灵的还原基团为分子中碳碳双键。

STUDIES ON ELECTROCHEMICAL BEHAVIOUR OF ANTIEPILEPSIRINE AND ITS ADSORPTIVE VOLTAMMETRY

Antiepilepsirine is a kind of new antiepileptic drug. In this paper, a new method, adsorptive voltammetry(ADV) has been established for the determination of antiepilepsirine. In 0. 20 mol/L H₂SO₄ solution, a sensitive reduction wave of antiepilepsirine was obtained by ADV after preconcentration on the surface of hanging mercury drop electrode (HMDE) (Ei= 0.7V, v =100 mV/s), the peak potential was--0.94V(vs Ag/AgCl). The linear range between the peak current and the concentration of antiepilepsirine was 3. 0×10^-9～3. 0×10^-6mol/L with a detection limit of 1.0×10^-9mol/L. Antiepilepsirine in tablet and urine samples was determined by using this method. The electrochemical behaviour of the system and its electrode reaction mechanism were studied by means of linear sweep and cyclic voltammetry, constant potential coulometry, normal pulse polarography (NPP), etc. The diffusion coefficient D was 7.7×10^-6cm²/s. The electrode reaction rate constant was 1.5×10^-3cm/s. The number of reduction electron n was 2. The electron transfer coefficient was 0.52. The electrode reduction process was shown to be irreversible with the adsorptive characteristics.