Determination of Salicylic Acid by Differential Pulse Voltammetry with an Electro-activated Glassy Carbon Electrode

The electrochemical behavior of salicylic acid(SA) on an electro-activated glassy carbon electrode(EGCE) was studied by cyclic voltammetry(CV) and differential pulse voltammetry(DPV).The glassy carbon electrode(GCE) was activated in pH 7.0 PBS buffer for 400 s by potentiostatic method at+1.7 V.In 0.2 mol·L-1 NaOH solution,a well-defined oxidative peak of SA was observed at 0.602 V(vs.Ag/AgCl) on the activated electrode.The anodic peak current increased linearly with scan rate from 0.02 V·s-1 to 0.2 V·s-1,revealing that the reaction was a absorption-controlled process.The experimental parameters were optimized and the correlation between peak current(Ipa) and concentration was studied by differential pulse voltammetry.Under the optimal conditions,the linear range for SA was in the range of 5.0×10-6-2.0×10-3 mol·L-1 with a correlation coefficient of 0.986 3,and the detection limit(S/N=3) was 1.2×10-7 mol·L-1.The activated glassy carbon electrode showed the advantages of simple preparation procedure and good reproducibility,and was applied in the determination of salicylic acid in pharmaceutical drugs with satisfactory results.