{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,7]],"date-time":"2026-02-07T09:23:42Z","timestamp":1770456222566,"version":"3.49.0"},"reference-count":48,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2021,2,7]],"date-time":"2021-02-07T00:00:00Z","timestamp":1612656000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"CEMMPRE","award":["UIDB\/EMS\/00285\/2020"],"award-info":[{"award-number":["UIDB\/EMS\/00285\/2020"]}]},{"name":"European Social Fund, Human Capital Operational Programme 2014-2020","award":["POCU\/380\/6\/13\/125171"],"award-info":[{"award-number":["POCU\/380\/6\/13\/125171"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>A novel hybrid composite of conductive poly(methylene blue) (PMB) and carbon nanotubes (CNT) was prepared for the detection of 5-aminosalicylic acid (5-ASA). Electrosynthesis of PMB with glassy carbon electrode (GCE) or with carbon nanotube modified GCE was done in ethaline deep eutectic solvent of choline chloride mixed with ethylene glycol and a 10% v\/v aqueous solution. Different sensor architectures were evaluated in a broad range of pH values in a Britton-Robinson (BR) buffer using electrochemical techniques, chronoamperometry (CA), and differential pulse voltammetry (DPV), to determine the optimum sensor configuration for 5-ASA sensing. Under optimal conditions, the best analytical performance was obtained with CNT\/PMBDES\/GCE in 0.04 M BR buffer pH 7.0 in the range 5\u2013100 \u00b5M 5-ASA using the DPV method, with an excellent sensitivity of 9.84 \u03bcA cm\u22122 \u03bcM\u22121 (4.9 % RSD, n = 5) and a detection limit (LOD) (3\u03c3\/slope) of 7.7 nM, outclassing most similar sensors found in the literature. The sensitivity of the same sensor obtained in CA (1.33 \u03bcA cm\u22122 \u03bcM\u22121) under optimal conditions (pH 7.0, Eapp = +0.40 V) was lower than that obtained by DPV. Simultaneous detection of 5-ASA and its analogue, acetaminophen (APAP), was successfully realized, showing a catalytic effect towards the electro-oxidation of both analytes, lowering their oxidation overpotential, and enhancing the oxidation peak currents and peak-to-peak separation as compared with the unmodified electrode. The proposed method is simple, sensitive, easy to apply, and economical for routine analysis.<\/jats:p>","DOI":"10.3390\/s21041161","type":"journal-article","created":{"date-parts":[[2021,2,10]],"date-time":"2021-02-10T04:33:46Z","timestamp":1612931626000},"page":"1161","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Hybrid Nanocomposite Platform, Based on Carbon Nanotubes and Poly(Methylene Blue) Redox Polymer Synthesized in Ethaline Deep Eutectic Solvent for Electrochemical Determination of 5-Aminosalicylic Acid"],"prefix":"10.3390","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3579-5195","authenticated-orcid":false,"given":"Oana","family":"Hosu","sequence":"first","affiliation":[{"name":"Department of Chemistry, CEMMPRE, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal"},{"name":"Department of Analytical Chemistry, Faculty of Pharmacy, \u201cIuliu Ha\u0163ieganu\u201d University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania"}]},{"given":"Madalina M.","family":"Barsan","sequence":"additional","affiliation":[{"name":"Department of Chemistry, CEMMPRE, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal"},{"name":"National Institute of Material Physics, 077125 Magurele, Romania"}]},{"given":"Robert","family":"S\u0103ndulescu","sequence":"additional","affiliation":[{"name":"Department of Analytical Chemistry, Faculty of Pharmacy, \u201cIuliu Ha\u0163ieganu\u201d University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4158-3324","authenticated-orcid":false,"given":"Cecilia","family":"Cristea","sequence":"additional","affiliation":[{"name":"Department of Analytical Chemistry, Faculty of Pharmacy, \u201cIuliu Ha\u0163ieganu\u201d University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1972-4434","authenticated-orcid":false,"given":"Christopher M. A.","family":"Brett","sequence":"additional","affiliation":[{"name":"Department of Chemistry, CEMMPRE, Faculty of Sciences and Technology, University of Coimbra, 3004-535 Coimbra, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2021,2,7]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"30","DOI":"10.1016\/j.apmt.2017.11.005","article-title":"Deep eutectic solvents for the production and application of new materials","volume":"10","author":"Brett","year":"2018","journal-title":"Appl. Mater. Today"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.coelec.2018.05.016","article-title":"Deep eutectic solvents and applications in electrochemical sensing","volume":"10","author":"Brett","year":"2018","journal-title":"Curr. Opin. 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