{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,27]],"date-time":"2026-07-27T11:30:21Z","timestamp":1785151821157,"version":"3.55.0"},"reference-count":34,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2019,2,6]],"date-time":"2019-02-06T00:00:00Z","timestamp":1549411200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>We modified and evaluated the performance of a CuO\/Cu electrochemical electrode for chemical oxygen demand (COD) determination by covering it with a Nafion (Nf) film. The resulting modified CuONf\/Cu electrode sensor was used for the electrochemical determination of COD in river, slaughterhouse and estuarine water samples in order to evaluate its performance for this particular task. It was compared with the CuO\/Cu sensor with no Nafion. The main electrochemical characteristics of interest, resistance, sensitivity, accuracy and reproducibility, were assessed by means of Linear Sweep Voltammetry using glucose as a standard. Results of these essays indicate that the procedure used produced smooth and firmly attached Nf films covering the whole copper surface. This sensor was shown to be resistant to interferences and effective in electro-oxidation of a wide range of organic compounds and therefore very useful for COD determination. Using the newly developed CuONf\/Cu electrode an analytical linear range of 50 to 1000 mg\u00b7L\u22121 COD, with a detection limit of 2.11 mg\u00b7L\u22121 (n = 6) COD was achieved. The comparison shows that the CuONf\/Cu sensor is more appropriate for COD determination than its counterpart with no Nafion.<\/jats:p>","DOI":"10.3390\/s19030669","type":"journal-article","created":{"date-parts":[[2019,2,6]],"date-time":"2019-02-06T11:51:12Z","timestamp":1549453872000},"page":"669","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":32,"title":["A Nafion Film Cover to Enhance the Analytical Performance of the CuO\/Cu Electrochemical Sensor for Determination of Chemical Oxygen Demand"],"prefix":"10.3390","volume":"19","author":[{"given":"Tanya","family":"Carchi","sequence":"first","affiliation":[{"name":"Grupo BIOeng, Escuela de Ingenier\u00eda Qu\u00edmica, Universidad T\u00e9cnica de Machala, Apartado 070151, Machala, Ecuador"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8556-1442","authenticated-orcid":false,"given":"Byron","family":"Lapo","sequence":"additional","affiliation":[{"name":"Grupo BIOeng, Escuela de Ingenier\u00eda Qu\u00edmica, Universidad T\u00e9cnica de Machala, Apartado 070151, Machala, Ecuador"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jos\u00e9","family":"Alvarado","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica, Universidad Sim\u00f3n Bol\u00edvar, Apartado 89000, Caracas, Venezuela"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0592-8652","authenticated-orcid":false,"given":"Patricio J.","family":"Espinoza-Montero","sequence":"additional","affiliation":[{"name":"Pontificia Universidad Cat\u00f3lica del Ecuador, Escuela de Ciencias Qu\u00edmicas, Avenida 12 de octubre y Roca, Apartado 17-01-2184, Quito, Ecuador"},{"name":"Escuela Polit\u00e9cnica Nacional, Escuela de Formaci\u00f3n de Tecn\u00f3logos, Apartado 17-01-2759, Quito, Ecuador"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7447-9582","authenticated-orcid":false,"given":"Jordi","family":"Llorca","sequence":"additional","affiliation":[{"name":"Institut de T\u00e8cniques Energ\u00e8tiques and Centre for Research in Nanoengineering, Universitat Polit\u00e8cnica de Catalunya, Barcelona 08034, Spain"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lenys","family":"Fern\u00e1ndez","sequence":"additional","affiliation":[{"name":"Departamento de Qu\u00edmica, Universidad Sim\u00f3n Bol\u00edvar, Apartado 89000, Caracas, Venezuela"},{"name":"Pontificia Universidad Cat\u00f3lica del Ecuador, Escuela de Ciencias Qu\u00edmicas, Avenida 12 de octubre y Roca, Apartado 17-01-2184, Quito, Ecuador"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2019,2,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2334","DOI":"10.1021\/ac00289a036","article-title":"Comparison of the microcolorimetric and macrotitrimetric methods for chemical oxygen demand of oil shale wastewater","volume":"57","author":"Jones","year":"1985","journal-title":"Anal. 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