Electrochemical Detection of Capsaicin in Chili Pepper Using Molecular Imprinted Poly β-Cyclodextrin Embedded Graphite (MIP-β-CD@G) Electrode

In this paper, a molecular imprinted poly $\beta $ cyclodextrin embedded graphite (MIP- $\beta $ -CD@G) electrode is reported, which has been developed for electrochemical determination of capsaicin (CP). MIP- $\beta $ -CD@G has been synthesized by copolymerization of $\beta $ -cyclodextrin ( $\beta $ -CD), ethylene glycol dimethacrylate (EGDMA) along with graphite powder and CP molecule in presence of benzoyl peroxide (BP). In the ultra violet – visible (UV-Vis.) spectrum, the disappearance of absorption peak of CP confirms the successful leaching out of the target molecule upon its extraction during the formation of MIP. Cyclic voltammetry (CV) responses revealed that MIP- $\beta $ -CD@G electrode showed remarkable increase in peak current towards electro-oxidation of CP as compared to non-imprinted polymer (NIP) electrode. Under optimized experimental condition, MIP- $\beta $ -CD@G maintained linear relationship between concentration of CP vs. peak current in the range of $0.1~\mu \text{M} - 1.0~\mu \text{M}$ and $1.0~\mu \text{M} - 180~\mu \text{M}$ for the $\beta $ cyclodextrin embedded graphite electrode. The lower limit of detection (LOD) towards CP was found to be $0.007~\mu \text{M}$ (S/N = 3) with the fabricated electrode. The practical applicability of MIP- $\beta $ -CD@G electrode was tested with green chili pepper extracts which yielded satisfactory results.