A Novel Chiral Molecularly Imprinted Electrochemical Sensor Based on β-CD Functionalized Graphene Quantum Dots for Enantioselective Detection of D-Carnitine

TL;DR

A new sensor using graphene quantum dots and cyclodextrin improves detection of D-carnitine with high selectivity and accuracy.

Contribution

A novel chiral sensor using β-CD functionalized GQDs in MIPs for enantioselective detection of D-carnitine is developed.

Findings

The sensor detects D-carnitine with a detection limit of 2.35 × 10−13 mol/L.

The sensor shows a 7.15-fold improvement in selectivity for D-carnitine recognition.

Real sample tests achieved recovery rates of 98.5% to 103.0% for D-carnitine.

Abstract

In this study, β-cyclodextrin (β-CD) functionalized graphene quantum dots (GQDs) was employed to augment the array of chiral recognition sites, thereby enhancing the affinity of GQDs/β-CD composite for imprinting molecules and realizing heightened chiral selectivity. The incorporation of GQDs/β-CD into the synthesis of molecularly imprinted polymers (MIPs), synergizing with the host-guest inclusion properties of β-CD and the abundant carboxyl groups of GQDs, enhanced the chiral recognition capacity of MIPs materials. Consequently, a novel MIPs/(GQDs/β-CD) sensor with chiral recognition capabilities tailored for D-carnitine was successfully fabricated. The binding mechanism between GQDs/β-CD and D-carnitine was elucidated via Ultraviolet-visible spectroscopy and Fourier transform infrared spectroscopy. The variation in the response signal (ΔI) of the probe molecule exhibited a linear correlation with the logarithm of D-carnitine concentration (lgC) in the range of 1.0 × 10−12 mol/L to 1.0 × 10−9 mol/L, and the detection limit (3δ/S) was calculated as 2.35 × 10−13 mol/L. These results underscore a 7.15-fold enhancement in the selectivity of MIPs/(GQDs/β-CD) sensor for D-carnitine recognition. Moreover, the sensor presented commendable efficacy in real-world scenarios, yielding recovery rates ranging from 98.5% to 103.0% during the determination of D-carnitine content in real samples.

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