Fe2O3–MgO–CuO@MWCNT Nanocomposite for Highly Sensitive Electrochemical Detection of l -Cysteine at Low Potential in Biological Samples
- 1Universidade Federal do Maranhão , Avenida dos Portugueses, No 1966, Bacanga , , ,
- 2Instituto Federal de Educação, Ciência e Tecnologia do Maranhão , Avenida Getúlio Vargas, No 04, Monte Castelo , , ,
Abstract
A Fe2O3–MgO–CuO composite integrated with multiwalled carbon nanotubes (MWCNTs) was employed to develop a platform for the indirect electrochemical detection of l-cysteine (l-CYS). The material was characterized by XRD, FTIR, SEM, EDS, and EIS, confirming the formation of a hybrid nanostructure. After optimization of the experimental parameters, the modified glassy carbon electrode exhibited a well-defined cathodic response at −0.25 V vs Ag/AgCl (saturated KCl). Although l-CYS undergoes electrochemical oxidation at positive potentials (approximately +0.25 V), quantitative analysis was based on the effect of the presence of l-CYS on the cathodic response of the modified electrode. The determination of the analyte was performed using linear sweep voltammetry, yielding two linear response ranges of 0.5–100 μmol L–1 (R2 = 0.992) and 100–1000 μmol L–1 (R2 = 0.996). The lowest detectable concentration of l-CYS with the Fe2O3–MgO–CuO@MWCNT/GCE electrode was 0.5 μmol L–1. The sensor exhibited high selectivity, excellent repeatability (RSD = 1.58%), and reproducibility (RSD = 1.82%). The sensor was evaluated for l-CYS determination in urine and breast milk samples, providing satisfactory recovery values.
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BibTeX
@article{ribeiro2026fe2o3mgocuomwcnt,
title = {{Fe2O3–MgO–CuO@MWCNT Nanocomposite for Highly Sensitive Electrochemical Detection of l -Cysteine at Low Potential in Biological Samples}},
author = {Danilo B. Ribeiro and Carolina A. Carvalho and Natilene M. Brito and Flavio S. Damos and Rita C. S. Luz},
journal = {ACS Omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c05509},
url = {https://pubs.acs.org/acsodf/article/11/42/64840/5451449/Fe2O3-MgO-CuO-MWCNT-Nanocomposite-for-Highly},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Fe2O3–MgO–CuO@MWCNT Nanocomposite for Highly Sensitive Electrochemical Detection of l -Cysteine at Low Potential in Biological Samples
AU - Danilo B. Ribeiro
AU - Carolina A. Carvalho
AU - Natilene M. Brito
AU - Flavio S. Damos
AU - Rita C. S. Luz
PY - 2026
DA - 2026/10/14
JO - ACS Omega
DO - 10.1021/acsomega.6c05509
UR - https://pubs.acs.org/acsodf/article/11/42/64840/5451449/Fe2O3-MgO-CuO-MWCNT-Nanocomposite-for-Highly
AB - A Fe2O3–MgO–CuO composite integrated with multiwalled carbon nanotubes (MWCNTs) was employed to develop a platform for the indirect electrochemical detection of l-cysteine (l-CYS). The material was characterized by XRD, FTIR, SEM, EDS, and EIS, confirming the formation of a hybrid nanostructure. After optimization of the experimental parameters, the modified glassy carbon electrode exhibited a well-defined cathodic response at −0.25 V vs Ag/AgCl (saturated KCl). Although l-CYS undergoes electrochemical oxidation at positive potentials (approximately +0.25 V), quantitative analysis was based on the effect of the presence of l-CYS on the cathodic response of the modified electrode. The determination of the analyte was performed using linear sweep voltammetry, yielding two linear response ranges of 0.5–100 μmol L–1 (R2 = 0.992) and 100–1000 μmol L–1 (R2 = 0.996). The lowest detectable concentration of l-CYS with the Fe2O3–MgO–CuO@MWCNT/GCE electrode was 0.5 μmol L–1. The sensor exhibited high selectivity, excellent repeatability (RSD = 1.58%), and reproducibility (RSD = 1.82%). The sensor was evaluated for l-CYS determination in urine and breast milk samples, providing satisfactory recovery values.
SN - 2470-1343
ER -