Electrochemical Detection of Epicatechin in Green Tea Using Quercetin-Imprinted Polymer Graphite Electrode
Debangana Das, Shreya Nag, Shubham De, Ajanto Kumar Hazarika, Santanu Sabhapondit, Bipan Tudu, Rajib Bandyopadhyay, Panchanan Pramanik, Runu Banerjee Roy
Abstract
The current study utilizes molecularly imprinted polymer (MIP) technology to fabricate a cost-effective and reproducible electrode for selective determination and quantitative prediction of epicatechin (EC) in green tea. Acrylamide (AAm) co-polymerized with ethylene glycol dimethacrylate (EGDMA) and optically inactive quercetin (Q) as the template has been used to make the MIP-Q@G material. The voltammetric experiment has been performed using the MIP-Q@G electrode with the help of a three-electrode configuration. In addition to a low detection limit (LoD) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.33 ~\mu \text{M}$ </tex-math></inline-formula> , the electrode exhibited two wide ranges of linearity from <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1 ~\mu \text{M}$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100 ~\mu \text{M}$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$100 ~\mu \text{M}$ </tex-math></inline-formula> to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$500 ~\mu \text{M}$ </tex-math></inline-formula> . The limit of quantitation (LoQ) of the electrode was found to be <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.09 ~\mu \text{M}$ </tex-math></inline-formula> . Partial least square regression (PLSR) and principal component regression (PCR) models have been developed to investigate the predictive ability of the MIP-Q@G electrode using the differential pulse voltammetry (DPV) signals and the high- performance liquid chromatography (HPLC) data. Both PLSR and PCR models achieved prediction accuracies of 94.54 % and 94.41% with a root mean square error of calibration (RMSEC) of 0.113 and 0.119, respectively.