Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample Analysis

Dopamine (DA) is a neurotransmitter responsible for important functions in mammals’ bodies, including mood, movement and motivation. High or low dopamine levels are associated mainly with mental illnesses such as schizophrenia and depression. Therefore, contributing to the development of electrochem...

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Main Authors: Alencastro Gabriel Ribeiro Lopes, Rafael Matias Silva, Orlando Fatibello-Filho, Tiago Almeida Silva
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Chemosensors
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Online Access:https://www.mdpi.com/2227-9040/13/7/254
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author Alencastro Gabriel Ribeiro Lopes
Rafael Matias Silva
Orlando Fatibello-Filho
Tiago Almeida Silva
author_facet Alencastro Gabriel Ribeiro Lopes
Rafael Matias Silva
Orlando Fatibello-Filho
Tiago Almeida Silva
author_sort Alencastro Gabriel Ribeiro Lopes
collection DOAJ
description Dopamine (DA) is a neurotransmitter responsible for important functions in mammals’ bodies, including mood, movement and motivation. High or low dopamine levels are associated mainly with mental illnesses such as schizophrenia and depression. Therefore, contributing to the development of electrochemical devices to precisely determine the DA levels in urine samples, a simple and low-cost sensor is proposed in this work. The proposed sensor design is based on crosslinked chitosan films combining carbon black (CB) and deep eutectic solvents (DESs), incorporated onto the surface of a glassy carbon electrode (GCE). Fourier Transform Infrared Spectroscopy (FT-IR) was applied to characterize the produced DESs and their precursors, while the films were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The sensor modified with CB and DES–ethaline (DES (ETHA)-CB/GCE) showed a significantly enhanced analytical signal for DA using differential pulse voltammetry under the optimized working conditions. Moreover, a better heterogeneous electron transfer rate constant (<i>k</i><sup>0</sup>) was obtained, about 45 times higher than that of the bare GCE. The proposed sensor achieved a linear response range of 0.498 to 26.8 µmol L<sup>−1</sup> and limits of detection and quantification of 80.7 and 269 nmol L<sup>−1</sup>, respectively. Moreover, the sensor was successfully applied in the quantification of DA in the synthetic urine samples, with recovery results close to 100%. Furthermore, the sensor presented good precision, as shown from the repeatability tests. The presented method to electrochemically detect DA has proven to be efficient and simple compared to the conventional methods commonly reported.
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spelling doaj-art-4dde0d6d1dda49c585923778ea2c54482025-08-20T03:35:37ZengMDPI AGChemosensors2227-90402025-07-0113725410.3390/chemosensors13070254Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample AnalysisAlencastro Gabriel Ribeiro Lopes0Rafael Matias Silva1Orlando Fatibello-Filho2Tiago Almeida Silva3Department of Chemistry, Federal University of Viçosa, Viçosa 36570-900, MG, BrazilDepartment of Chemistry, Federal University of Viçosa, Viçosa 36570-900, MG, BrazilDepartment of Chemistry, Federal University of São Carlos, São Carlos 13565-905, SP, BrazilDepartment of Chemistry, Federal University of Viçosa, Viçosa 36570-900, MG, BrazilDopamine (DA) is a neurotransmitter responsible for important functions in mammals’ bodies, including mood, movement and motivation. High or low dopamine levels are associated mainly with mental illnesses such as schizophrenia and depression. Therefore, contributing to the development of electrochemical devices to precisely determine the DA levels in urine samples, a simple and low-cost sensor is proposed in this work. The proposed sensor design is based on crosslinked chitosan films combining carbon black (CB) and deep eutectic solvents (DESs), incorporated onto the surface of a glassy carbon electrode (GCE). Fourier Transform Infrared Spectroscopy (FT-IR) was applied to characterize the produced DESs and their precursors, while the films were characterized by scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV). The sensor modified with CB and DES–ethaline (DES (ETHA)-CB/GCE) showed a significantly enhanced analytical signal for DA using differential pulse voltammetry under the optimized working conditions. Moreover, a better heterogeneous electron transfer rate constant (<i>k</i><sup>0</sup>) was obtained, about 45 times higher than that of the bare GCE. The proposed sensor achieved a linear response range of 0.498 to 26.8 µmol L<sup>−1</sup> and limits of detection and quantification of 80.7 and 269 nmol L<sup>−1</sup>, respectively. Moreover, the sensor was successfully applied in the quantification of DA in the synthetic urine samples, with recovery results close to 100%. Furthermore, the sensor presented good precision, as shown from the repeatability tests. The presented method to electrochemically detect DA has proven to be efficient and simple compared to the conventional methods commonly reported.https://www.mdpi.com/2227-9040/13/7/254electrochemical sensorsneurotransmittergreen solventscarbonaceous materialsgreen chemistry
spellingShingle Alencastro Gabriel Ribeiro Lopes
Rafael Matias Silva
Orlando Fatibello-Filho
Tiago Almeida Silva
Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample Analysis
Chemosensors
electrochemical sensors
neurotransmitter
green solvents
carbonaceous materials
green chemistry
title Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample Analysis
title_full Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample Analysis
title_fullStr Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample Analysis
title_full_unstemmed Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample Analysis
title_short Electrochemical Sensing of Dopamine Neurotransmitter by Deep Eutectic Solvent–Carbon Black–Crosslinked Chitosan Films: Charge Transfer Kinetic Studies and Biological Sample Analysis
title_sort electrochemical sensing of dopamine neurotransmitter by deep eutectic solvent carbon black crosslinked chitosan films charge transfer kinetic studies and biological sample analysis
topic electrochemical sensors
neurotransmitter
green solvents
carbonaceous materials
green chemistry
url https://www.mdpi.com/2227-9040/13/7/254
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