Amine Functionalized MWCNTs Modified MIP-Based Electrode for Detection of Epicatechin in Tea

The present work utilizes the molecular imprinted polymer technology for the fabrication of a stable and reproducible electrode for the detection of epicatechin (EC) in tea. The polymer-graphite composite embedded with amine functionalized multi-walled carbon nanotubes (f-MWCNTs) was prepared and used as the sensing material. The sensing materials of the MIP-EC electrode were characterized by field emission gun scanning electron microscopy, transmission electron microscopy and fourier transform infrared spectroscopy. A wide linearity change from $1~ \boldsymbol {\mu }\text{M}$ – $30~ \boldsymbol {\mu }\text{M}$ and 30 $\boldsymbol {\mu }\text{M}$ - 300 $\boldsymbol {\mu }\text{M}$ , detection limit of 51.92 nM and quantification limit of $0.17~ \boldsymbol {\mu } \text{M}$ were obtained with the electrode. To predict the content of EC, two linear regression models were developed, using the differential pulse voltammetry responses and high-performance liquid chromatography analysis results as reference data. Prediction accuracies of 92% using principal component regression (PCR) and 93.58% using partial least square regression (PLSR) were obtained. The root mean square error of calibration for PLSR and PCR was 0.29 and 0.31 using 6 and 10 latent variables, respectively. The stability of the electrode was found to be of approximately 90 days.