Acta Phys. -Chim. Sin. ›› 1993, Vol. 9 ›› Issue (02): 175-180.doi: 10.3866/PKU.WHXB19930207

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Study on the Polarographic Behaviors of Morin

Li Nan-Qiang; Xu You-Xuan   

  1. Department of Chemistry, Peking University, Beijing 100871
  • Received:1991-10-07 Revised:1992-04-02 Published:1993-04-15
  • Contact: Li Nan-Qiang

Abstract: The electrochemical properties of morin(MOR)over the entire pH range were studied. Four reduction waves were obtained. P_1 is a surface catalytic hydrogen wave. The other three waves have been proved as adsorptive waves. The electrode processes have been verified as being an EC mechanism. The reduction electron number of P_2 was determined as one by using DC polarography. At pH 6.6, on the surface of mercury electrode, the adsorption of MOR obeys Temkin isotherm. The adsorption coef-ficient β=9.3×10~6 and the experimental constant g=2.2×10~(-10) mol·cm~(-2) has been calculated. The adsorption type is considered as a flat orientation on the surface of the mercury electrode.
In 0.2 mol·L~(-1) sodium hydroxide solution, P_3 and P_4 can be obtained. n_3=1, n_4=1 have been determined by using DC adsorptive current formula and peak area measurement. The potential of P_3 and P_4 shift positively with the increase of pH. It has been suggested that hydroxide ion participates in the electrode reaction.

Key words: Morin, Polarographic catalytic hydrogen wave, Polarographic adsorption waves, Voltammetry