INVESTIGATION ON DIFFERENTIAL PULSE POLAROGRAPHY——VI.THE POLAROGRAPHIC CURRENT OF CYTOSINE ON DROPPING MERCURY ELECTRODE

The differential pulse polarography of oytosine has been studied.It is found that in 0.1M HOAc-NaOAc buffer solution(pH=4.2)on DME cytosine shows a single reduction peak whioh obeys the following equation, i_r=i_(ads)x+i_((?)ff)(1-x)=0.480 nFm~(2/3)t_1~2C_M~*(?) where Ψ=(θ_1-θ_2)/(1+θ_1)(1+θ_2); θ_1=exp (nF)/(RT)(E-E'); θ_2=θ_1exp (nF)/(RT)⊿E; E'=E~0+RT/nF·ln(D_R/D_0)~(1/2)+RT/nF ln0.81 K (?) [H~+]~(3/2) In these equations,C_M~* denotes the bulk concentration of cytosine,K,k_(?) are the chemieal equilibrium constant and the rate constant of chemical reaction respectively and β is related to x by the following equation x-(β-1)/[0.858+0.142(β-1)] The β value has been determined experimentally and the value of x calculated from the equation was 0.290.The diffusion coefficient value(D)of cytosine agrees with that obtained by the D.C.polarographic method. The theoretical values of the differential pulse polarographic currents were calcula- ted by means of the above equation and it is found that the experimental values agree with the theoretical ones.