{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T11:33:04Z","timestamp":1789471984134,"version":"build-2803163510"},"reference-count":27,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2017,12,22]],"date-time":"2017-12-22T00:00:00Z","timestamp":1513900800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100000038","name":"Natural Sciences and Engineering Research Council of Canada","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000038","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000196","name":"Canada Foundation for Innovation","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000196","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>In this study, simultaneous electrochemical detection of ascorbic acid (AA), dopamine (DA), and uric acid (UA) was performed using a modified graphite paste electrode (MGPE) with epigallocatechin gallate (EGCG) and green tea (GT) powder. It was shown that the anodic peak current increased in comparison with that of the graphite paste electrode (GPE) in the cyclic voltammograms. The optimal pH for simultaneous determination of a quaternary mixture of AA\u2013DA\u2013UA was determined to be pH 2. The anodic peak potentials for a mixture containing AA\u2013DA\u2013UA were well separated from each other. The catalytic peak currents obtained at the surface of the MGPE\/EGCG were linearly dependent on the AA, DA, and UA concentrations up to 23, 14, and 14 \u00b5M, respectively. The detection limits for AA, DA, and UA were 190, 90, and 70 nM, respectively. The analytical performance of this sensor has been evaluated for simultaneous detection of AA, DA, and UA in real samples. Finally, a modified electrode was prepared using GT and used for simultaneous determination of AA, DA, and UA. Based on the results, MPGE\/GT showed two oxidation peaks at 0.43 and 0.6 V for DA and UA, respectively, without any oxidation peak for AA. The calibration curves at the surface of MGPE\/GT were linear up to 14 \u00b5M with a detection limit of 0.18 and 0.33 \u00b5M for DA and UA, respectively. MGPEs provide a promising platform for the future development of sensors for multiplexed electrochemical detection of clinically important analytes.<\/jats:p>","DOI":"10.3390\/s18010023","type":"journal-article","created":{"date-parts":[[2017,12,22]],"date-time":"2017-12-22T11:38:04Z","timestamp":1513942684000},"page":"23","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":25,"title":["Epigallocatechin Gallate-Modified Graphite Paste Electrode for Simultaneous Detection of Redox-Active Biomolecules"],"prefix":"10.3390","volume":"18","author":[{"given":"Hashwin","family":"Ganesh","sequence":"first","affiliation":[{"name":"Department of Physical and Environmental Sciences, University of Toronto, Scarborough 1265 Military Trail, Toronto, ON M1C 1A4, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Meissam","family":"Noroozifar","sequence":"additional","affiliation":[{"name":"Analytical Research Laboratory, Department of Chemistry, University of Sistan and Baluchestan, P.O. Box 98135-674, Zahedan, Iran"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-3511-8570","authenticated-orcid":false,"given":"Kagan","family":"Kerman","sequence":"additional","affiliation":[{"name":"Department of Physical and Environmental Sciences, University of Toronto, Scarborough 1265 Military Trail, Toronto, ON M1C 1A4, Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2017,12,22]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"334","DOI":"10.1016\/0091-7435(92)90041-F","article-title":"Green tea composition, consumption, and polyphenol chemistry","volume":"21","author":"Graham","year":"1992","journal-title":"Prev. Med."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"139","DOI":"10.1007\/s11130-007-0054-8","article-title":"Chemical composition of green tea (Camellia sinensis) infusions commercialized in Portugal","volume":"62","author":"Reto","year":"2007","journal-title":"Plant Foods Hum. Nutr."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"136","DOI":"10.4103\/2231-4040.97298","article-title":"Evaluation of anti-inflammatory effects of green tea and black tea\u2014A comparative in vitro study","volume":"3","author":"Chatterjee","year":"2012","journal-title":"J. Adv. Pharm. Technol. Res."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1186\/1476-9255-4-1","article-title":"Green tea increases anti-inflammatory tristetraprolin and decreases pro-inflammatory tumor necrosis factor mRNA levels in rats","volume":"4","author":"Cao","year":"2007","journal-title":"J. Inflamm."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"435","DOI":"10.1007\/s10555-010-9236-1","article-title":"Cancer and metastasis: Prevention and treatment by green tea","volume":"29","author":"Khan","year":"2011","journal-title":"Cancer Metastasis Rev."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"520","DOI":"10.5306\/wjco.v5.i3.520","article-title":"Green tea compounds in breast cancer prevention and treatment","volume":"5","author":"Li","year":"2014","journal-title":"World J. Clin. Oncol."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"41","DOI":"10.1111\/j.1753-4887.2011.00440.x","article-title":"Therapeutic potential of green tea in nonalcoholic fatty liver disease","volume":"70","author":"Masterjohn","year":"2012","journal-title":"Nutr. Rev."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"259","DOI":"10.1039\/c3mt20106f","article-title":"Electroanalysis of the interaction between (\u2212)-epigallocatechin-3-gallate (EGCG) and amyloid-\u03b2 in the presence of copper","volume":"5","author":"Zhang","year":"2013","journal-title":"Metallomics"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"2049","DOI":"10.1021\/ac303181q","article-title":"Surface plasmon resonance imaging of amyloid-\u03b2 aggregation kinetics in the presence of epigallocatechin gallate and metals","volume":"85","author":"Cheng","year":"2013","journal-title":"Anal. Chem."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"7710","DOI":"10.1073\/pnas.0910723107","article-title":"EGCG remodels mature \u03b1-synuclein and amyloid-\u03b2 fibrils and reduces cellular toxicity","volume":"107","author":"Bieschke","year":"2010","journal-title":"Proc. Natl. Acad. Sci. USA"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1038\/nchembio.719","article-title":"Small-molecule conversion of toxic oligomers to nontoxic \u03b2-sheet\u2013rich amyloid fibrils","volume":"8","author":"Bieschke","year":"2011","journal-title":"Nat. Chem. Biol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"558","DOI":"10.1038\/nsmb.1437","article-title":"EGCG redirects amyloidogenic polypeptides into unstructured, off-pathway oligomers","volume":"15","author":"Ehrnhoefer","year":"2008","journal-title":"Nat. Struct. Mol. Biol."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1007\/s12263-009-0143-4","article-title":"Neuroprotective molecular mechanisms of (\u2212)-epigallocatechin-3-gallate: A reflective outcome of its antioxidant, iron chelating and neuritogenic properties","volume":"4","author":"Weinreb","year":"2009","journal-title":"Genes Nutr."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"249","DOI":"10.1016\/j.jelechem.2003.09.018","article-title":"Electrochemical modification of benzo-15-crown-5 ether on a glassy carbon electrode for alkali metal cation recognition","volume":"563","author":"Morita","year":"2004","journal-title":"J. Electroanal. Chem."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"5126","DOI":"10.1016\/j.electacta.2005.01.056","article-title":"Electrocatalytic oxygen reduction on glassy carbon grafted with anthraquinone by anodic oxidation of a carboxylate substituent","volume":"50","author":"Vaik","year":"2005","journal-title":"Electrochim. Acta"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"5566","DOI":"10.1016\/j.electacta.2009.04.060","article-title":"Electrochemical stability of citrate-capped gold nanoparticles electrostatically assembled on amine-modified glassy carbon","volume":"54","author":"Cruickshank","year":"2009","journal-title":"Electrochim. Acta"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"1899","DOI":"10.1007\/s00216-006-1065-2","article-title":"Amperometric biosensor for the determination of creatine","volume":"387","author":"Ramanavicius","year":"2007","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"790","DOI":"10.1016\/j.bios.2010.06.023","article-title":"Enzymatically synthesized polyaniline layer for extension of linear detection region of amperometric glucose biosensor","volume":"26","author":"Mazeiko","year":"2010","journal-title":"Biosens. Bioelectron."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"6426","DOI":"10.1016\/j.electacta.2009.06.015","article-title":"EDTA modified glassy carbon electrode: Preparation and characterization","volume":"54","author":"Ustundag","year":"2009","journal-title":"Electrochim. Acta"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"1924","DOI":"10.1039\/C5AY02911B","article-title":"Graphite paste electrode modified with Lewatit\u00ae FO36 nano-resin for simultaneous determination of ascorbic acid, acetaminophen and tryptophan","volume":"8","author":"Rajabi","year":"2016","journal-title":"Anal. Methods"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"11763","DOI":"10.20964\/2017.12.56","article-title":"Modified graphite paste electrode with strontium phen-dione complex for simultaneous determination of a ternary mixture of dopamine, acetaminophen and xanthine (Part II)","volume":"12","author":"Shahbakhsh","year":"2017","journal-title":"Int. J. Electrochem. Sci."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"10911","DOI":"10.20964\/2017.11.09","article-title":"Modified graphite paste electrode with strontium phen-dione complex for simultaneous determination of a ternary mixture of 4-aminophenol, uric Acid and tryptophan (Part I)","volume":"12","author":"Narouie","year":"2017","journal-title":"Int. J. Electrochem. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"239","DOI":"10.1016\/j.snb.2012.10.138","article-title":"Tailoring properties of polyaniline for simultaneous determination of a quaternary mixture of ascorbic acid, dopamine, uric acid, and tryptophan","volume":"177","author":"Srivastava","year":"2013","journal-title":"Sens. Actuators B Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"97","DOI":"10.1016\/j.colsurfb.2013.05.023","article-title":"Simultaneous and sensitive determination of ascorbic acid, dopamine, uric acid, and tryptophan with silver nanoparticles-decorated reduced graphene oxide modified electrode","volume":"111","author":"Kaur","year":"2013","journal-title":"Colloids Surf. B"},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"232","DOI":"10.1016\/j.snb.2014.12.120","article-title":"Simultaneous determination of ascorbic acid, uric acid, tryptophan and adenine using carbon-supported NiCoO2 nanoparticles","volume":"210","author":"Yang","year":"2015","journal-title":"Sens. Actuators B Chem."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"464","DOI":"10.1021\/acssensors.6b00250","article-title":"Wearable chemical sensors: Present challenges and future prospects","volume":"1","author":"Bandodkar","year":"2016","journal-title":"ACS Sens."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"468","DOI":"10.1021\/acssensors.7b00045","article-title":"Ingestible sensors","volume":"2","author":"Ha","year":"2017","journal-title":"ACS Sens."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/1\/23\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T18:55:09Z","timestamp":1760208909000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/18\/1\/23"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2017,12,22]]},"references-count":27,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2018,1]]}},"alternative-id":["s18010023"],"URL":"https:\/\/doi.org\/10.3390\/s18010023","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2017,12,22]]}}}