Adsorptive Voltammetric Behavior of Riboflavine Tetrabut yrate and Its Measurement of Rate Constant at the Mercury Electrode / 分析化学

ABSTRACT

Cyclic voltammetry shows that, in a supporting ele ctrolyte of NaOH,riboflavine tetrabutyrate（RT）has a pair of cathodic and anodi c peaks at Hg electrode. The peak potentials Epc=Epa=-0.64　 V（vs.Ag/Agcl）.　The adsorptive characteristics of RT are explored in detai ls with various methods.　The adsorbed species is most probably neutral molecule of RT.The saturated adsorption amount of RT at Hg electrode is 5.42×10-11 　mol/cm2 and every RT molecule occupied 3.06　nm2. On the surface of HMDE ，the adsorption of RT obeys Frumkin dasorption isotherm. The adsorptive coeffic ient β，the attractive factor γ are 4.60×105，1.10 and the adsorption free energy ΔG, is　－32.30　kJ/mol, respectively. The electrode proc ess kinetic behavior has also been studied by using cyclic voltammetry. Under th e experimental conditions the rate constants for electron transfer are determine d. The values of ks are in good agreement with literature′s results.