双嘧达莫在汞电极上的电化学行为和吸附性质

在NaOH底液中,双嘧达莫在汞电极上有一不可逆的线性扫描还原峰,E_PC=—1.39V(vs饱和Ag/AgCl)。该峰具有明显的吸附性。当搅拌富集时间较长、双嘧达莫的浓度较小、扫描速度较快时,电极反应几乎完全为吸附态的双嘧达莫所控制。选相交流伏安等实验表明,吸附型体为双嘧达莫中性分子。测得该体系的电子转移数n为4,不可逆吸附的αn_α值为1.72。探讨了双嘧达莫的电极反应机理,建立了用吸附伏安法测定双嘧达莫的最佳条件。

ELECTROCHEMICAL BEHAVIOR AND ADSORPTIVE CHARACTERISTICS OF DIPYRIDAMOLE(PERSANTINE) AT MERCURY ELECTRODE

In a supporting electrolyte containing NaOH , an irreversible reduction peak ofdipyridamole( DPD ) was found by linear-sweep Voltammetry at Hg electrode. The peak shows apotentlaI Of 1.39 V(us Ag/AgCl)and adsorptive characteristics.When the concentration of DPDis sufficiently low ,the sweep rate sufficiently rapid and the accumulation time sufficiently long , thepeak current is almost totally contributed by the reduction of adsorbed DPD. The experiments of phaseselective AC voltammetry indicate that the adsorbed species is most probably neutral DPD molecule.The number of electrons transferred per DPD molecule,n,is 4 and the value of ana of the irreversibleadsorptive system of DPD is l.72.The mechanism of electrochemical reduction of DPD at HgeIectrode was explored. The optimized condition for measuring trace amount of DPD by adsorptivestripping voItammetry was established.