SiO2-modified carbon paste electrode for electrochemical determination of pyrogallol

A silica gel-modified carbon paste electrode (Si-CPE) was fabricated and used for determination of pyrogallol. Cyclic and differential pulse voltammetric studies show that Si-CPE lowers oxidation potential remarkably increases its oxidation peak current and improves electrochemical behavior of pyrogallol, compared to unmodified CPE. The effects of pH value, amount of silica, accumulation potential and time on the oxidation peak current of pyrogallol were examined. As a result, a sensitive, rapid and convenient electroanalytical method was developed for pyrogallol. The linear range is from 2 to 300 mu M, and the limit of detection is 0.7 mu M after 4.0 min accumulation. Interferences from some inorganic salts and organic compounds were studied. Finally, the method was successfully used to determine pyrogallol in tap water, green tea and artificial urine samples.