Electrochemical behavior of gallic acid at electro-activated glassy carbon electrode and its voltammetric determination

Electrochemical behavior of gallic acid(GA)at electro-activated glassy carbon electrode(EGCE)was studied by cyclic voltammetry(CV)and linear sweep voltammetry(LSV).The glassy carbon electrode(GCE)was activated in pH 7.0 phosphate buffer solution(PBS)for 400 s by potentiostatic method at+1.7 V.In pH 3.0 Citrate buffer solution(CBS),a well defined redox peak of gallic acid was observed at 0.479 V and 0.442 V with the activated electrode,The anodic peak current increased linearly with scan rate from 0.02 to 0.40 V·s-1,revealing that the reaction was a surface-controlled process.Experimental parameters were optimized and the correlation between peak current and concentration was studied by linear sweep voltammetry.Under the optimal conditions,the linear range for the detection of gallic acid was 1×10-6 to 1×10-4 mol·L-1 with a correlation coefficient of 0.980 6,and the low detection limit was 7.6×10-7 mol·L-1(S/N=3).The activated glassy carbon electrode is easy to be prepared with good reproducibility.The proposed methodology was successfully applied to the detection of gallic acid in Jianming Yanhou tablets with satisfactory results.