Highly sensitive determination of capsaicin using a carbon paste electrode modified with amino-functionalized mesoporous silica.

Mesoporous silica (MS) and amino-functionalized mesoporous silica (NH(2)-FMS) were prepared and characterized using the techniques of transmission electron microscopy (TEM) and nitrogen adsorption-desorption. Voltammetry was used to investigate the electrochemical behavior of capsaicin at the amino-functionalized mesoporous silica, which was modified through carbon paste electrode (NH(2)-FMS/CPE). NH(2)-FMS/CPE showed better performance for the electrochemical oxidation of capsaicin, when compared with bare carbon paste electrode (CPE) and mesoporous silica modified carbon paste electrode (MS/CPE). We optimized the experimental conditions influencing the determination of capsaicin. Under optimal conditions, the oxidation peak current was proportional to capsaicin concentration in the range of 0.040-0.40 μmol L(-1)and 0.40-4.0 μmol L(-1), when the detection limit was 0.020 μmol L(-1) (S/N=3). The above method was successfully applied to determine capsaicin in hot pepper samples, yielding satisfactory results. The spiked recoveries were in the range of 93.1-100.7%.