桑色素极谱行为的研究

研究了桑色素在pH=1～14的水溶液中的极谱行为. 于不同pH范翻内得列了四个还原波. 研究证实在pH<4条件下获得的P_1波为表面催化氢波. 其余三个波为不同形态桑色素的单电子吸附还原波, 并伴有随后化学反应过程. 测得在单分子层饱和吸附条件下, 每一个桑色素分子所占汞电极面积为1.36 nm.

STUDY ON THE POLAROGRAPHIC BEHAVIORS OF MORIN

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.