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

Mesoporous silica (MS) and amino-functionalized mesoporous silica (NH2-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 (NH2-FMS/CPE). NH2-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−1and 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%.