High Sensitivity Detection of Capsaicin in Red Pepper Oil Based on Reduced Graphene Oxide Enhanced by β-Cyclodextrin

Red pepper oil is a kind of condiment used in food factories, and its spicy degree can be reflected by the content of capsaicin. However, the classification method of red pepper oil is too subjective to be applied in food factories. In our work, a sensitivity electrochemical sensor for detecting capsaicin was constructed based on the glassy carbon electrode (GCE) modified with β-cyclodextrin (β-CD) assisted reduced graphene oxide (rGO). The results showed that the introduction of β-CD made rGO more dispersed, increasing the electrochemical active surface area of β-CD/rGO, thus improving the charge transfer rate. Furthermore, polycyclodextrin with selective recognition ability was dispersed on the surface of rGO, providing the possibility of capsaicin enrichment on the surface of the sensor. Based on these reasons, the sensor had a lower detection limit (0.05 μg/mL), and acceptable stability and anti-interference. Most importantly, β-CD/rGO/GCE displayed a satisfactory recovery rate (94.83 ~ 115.75%) in the detection of red pepper oil, and there was no statistical significance difference between this method and the LC–MS method.