Adsorptive Catalytic Voltammetric Determination of Chrysophanol at Carbon Paste Electrode

In an ammoniacal buffer solution of pH 9.5,and by accumulation at 0 V(vs.SCE) for 60 s scanning linearly from 0 to -1.0 V at the rate of 250 mV·s-1,a sensitive adsorptive catalytic voltammetric peak given by chrysophanol was observed at the carbon paste electrode at the potential of -0.61 V (vs.SCE).Linear relationship between values of 2nd derivative of peak current and concentration of chrysophanol was obtained in the range of 2.0×10-10-1.0×10-8mol·L-1,with its detection limit (3S/N) of 1.0×10-10mol·L-1.A preliminary discussion on the voltammetric behavior and electrochemical mechanism of electrode reaction of chrysophanol at both the carbon paste electrode and mercury electrode was also given.This method was used in the determination of chrysophanol in sample of seminacassiae,and using this sample as matrix,recovery was tested by standard additon method,giving results of recovery in the range of 96.8% to 104.8%.