Sensitive and Rapid Determination of Capsaicin Using Acetylene Black Nanoparticles Modified Electrode

Acetylene black (AB) nanoparticles were readily dispersed into N, N-dimethylformamide (DMF) via ultrasonication. After evaporation of DMF, the surface of glassy carbon electrode (GCE) was fully covered with AB nanoparticles as confirmed by scanning electron microscopy. From the transmission electron microscopy measurements, it was found that AB nanoparticles possessed porous structure. The electrochemical behavior of capsaicin was studied, and an irreversible oxidation peak was observed in pH 6.5 phosphate buffer. Compared with the unmodified GCE, AB nanoparticles-modified GCE greatly increased the oxidation peak current of capsaicin, exhibiting remarkable signal enhancement. The influences of pH value, amount of AB and accumulation time on the oxidation peak current of capsaicin were studied. As a result, a novel electrochemical method was developed for the detection of capsaicin. The linear range was from 5 to 300 mu g L-1, and the detection limit was 2.5 mu g L-1 (8.19 x 10(-9) M). Finally, this method was used to detect the content of capsaicin in different hot pepper samples, and the recovery was over the range from 98.2% to 99.1%.