Issue 5, 2021

Electroanalytical profiling of cocaine samples by means of an electropolymerized molecularly imprinted polymer using benzocaine as the template molecule

Abstract

The analysis of ‘cutting’ or additive agents in cocaine, like benzocaine (BZC), allows police analysts to identify each component of the sample, thus obtaining information like the drugs’ provenience. This kind of drug profiling is of great value in tackling drug trafficking. Electropolymerized molecularly imprinted polymers (e-MIPs) on portable screen-printed carbon electrodes (SPCEs) were developed in this study for BZC determination. The MIPs’ electropolymerization was performed on a carbon surface using the anaesthetic BZC as the template molecule and 3-amino-4-hydroxybenzoic acid (3,4-AHBA) as the functional monomer. The build-up of this biomimetic sensor was carefully characterized by cyclic voltammetry (CV) and optimized. Cyclic voltammetric investigation demonstrated that BZC oxidation had a complex and pH-dependent mechanism, but at pH 7.4 a single, well-defined oxidation feature was observed. The BZC-MIP interactions were studied by computer-aided theoretical modeling by means of density functional theory (DFT) calculations. The electroanalytical methodology was effectively applied to artificial urine samples; BZC molecular recognition was achieved with a low limit of detection (LOD) of 2.9 nmol L−1 employing square-wave voltammetry (SWV). The e-MIPs were then used to ‘fingerprint’ genuine cocaine samples, assisted by principal component analysis (PCA), at the central forensic laboratory of the Brazilian Federal Police (BFP) with a portable potentiostat. This electroanalysis provided proof-of-concept that the drugs could be voltammetrically ‘fingerprinted’ using e-MIPs supported by chemometric analysis.

Graphical abstract: Electroanalytical profiling of cocaine samples by means of an electropolymerized molecularly imprinted polymer using benzocaine as the template molecule

Supplementary files

Article information

Article type
Paper
Submitted
24 nov 2020
Accepted
12 jan 2021
First published
12 jan 2021

Analyst, 2021,146, 1747-1759

Electroanalytical profiling of cocaine samples by means of an electropolymerized molecularly imprinted polymer using benzocaine as the template molecule

R. A. Grothe, A. Lobato, B. Mounssef, N. Tasić, A. A. C. Braga, A. O. Maldaner, L. Aldous, T. R. L. C. Paixão and L. M. Gonçalves, Analyst, 2021, 146, 1747 DOI: 10.1039/D0AN02274H

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