{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,10,10]],"date-time":"2025-10-10T01:07:17Z","timestamp":1760058437438,"version":"build-2065373602"},"reference-count":22,"publisher":"MDPI AG","issue":"4","license":[{"start":{"date-parts":[[2025,4,2]],"date-time":"2025-04-02T00:00:00Z","timestamp":1743552000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"FCT\u2014Funda\u00e7\u00e3o para a Ci\u00eancia e Tecnologia","doi-asserted-by":"publisher","award":["2022.08713.PTDC","UIDB\/50016\/2020"],"award-info":[{"award-number":["2022.08713.PTDC","UIDB\/50016\/2020"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Faculty of Chemistry under the Strategic Programme Excellence Initiative","award":["2022.08713.PTDC","UIDB\/50016\/2020"],"award-info":[{"award-number":["2022.08713.PTDC","UIDB\/50016\/2020"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Chemosensors"],"abstract":"<jats:p>This paper focuses on the development of an environmentally friendly sequential injection (SI) method for the determination of chloride in water samples from dynamic water systems. Chloride quantification is highly relevant, as it may affect metal ion bioavailability and potential toxicity to the environment. The approach was established based on the catalytic reaction of chloride ions in the colorimetric reaction between 3,3\u2032,5,5\u2032-tetramethylbenzidine (TMB) and hydrogen peroxide. Optimisation studies were performed regarding several parameters such as reaction pH, reagent volume and concentration, reaction time, and flow rates. As such, it was possible to obtain a wide dynamic range of 60 to 1000 mM, with a limit of detection and quantification of 17 and 58 mM, respectively, and a relative standard deviation of 7%. Validation was performed by analysing 13 water samples from dynamic water systems, namely seawater, estuarine water, and estuarine harbour water, with the SI method developed and by comparing the results obtained to potentiometric titration as the reference method. The relative error of these comparisons was not significant (&lt;10%). Interference studies were also performed and showed no significant effect on the performance of the system (interference percentage &lt; 10%), proving that a robust and sensitive system was developed.<\/jats:p>","DOI":"10.3390\/chemosensors13040124","type":"journal-article","created":{"date-parts":[[2025,4,2]],"date-time":"2025-04-02T07:47:44Z","timestamp":1743580064000},"page":"124","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Chloride Catalytic Determination as Potential Tool to Assess Metal Ion Bioavailability in Water"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-2952-3510","authenticated-orcid":false,"given":"Mafalda G.","family":"Pereira","sequence":"first","affiliation":[{"name":"CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina, Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Universidade Cat\u00f3lica Portuguesa, CBQF, R. de Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9244-9080","authenticated-orcid":false,"given":"Justyna","family":"Paluch","sequence":"additional","affiliation":[{"name":"Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387 Krak\u00f3w, Poland"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7745-1860","authenticated-orcid":false,"given":"Raquel B. R.","family":"Mesquita","sequence":"additional","affiliation":[{"name":"CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina, Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Universidade Cat\u00f3lica Portuguesa, CBQF, R. de Diogo Botelho 1327, 4169-005 Porto, Portugal"}]},{"given":"Ant\u00f3nio O. S. S.","family":"Rangel","sequence":"additional","affiliation":[{"name":"CBQF\u2014Centro de Biotecnologia e Qu\u00edmica Fina, Laborat\u00f3rio Associado, Escola Superior de Biotecnologia, Universidade Cat\u00f3lica Portuguesa, CBQF, R. de Diogo Botelho 1327, 4169-005 Porto, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2025,4,2]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"142","DOI":"10.1016\/j.chemosphere.2019.04.198","article-title":"Removal of heavy metals from water sources in the developing world using low-cost materials: A review","volume":"229","author":"Joseph","year":"2019","journal-title":"Chemosphere"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"124364","DOI":"10.1016\/j.chemosphere.2019.124364","article-title":"Global evaluation of heavy metal content in surface water bodies: A meta-analysis using heavy metal pollution indices and multivariate statistical analyses","volume":"236","author":"Kumar","year":"2019","journal-title":"Chemosphere"},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"136810","DOI":"10.1016\/j.scitotenv.2020.136810","article-title":"DGT: A promising technology for in-situ measurement of metal speciation in the environment","volume":"715","author":"Gao","year":"2020","journal-title":"Sci. Total Environ."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"69","DOI":"10.1007\/s10311-015-0491-9","article-title":"Metal bioavailability and toxicity in freshwaters","volume":"13","author":"Baptista","year":"2015","journal-title":"Environ. Chem. Lett."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"48","DOI":"10.1002\/etc.4558","article-title":"Bioavailability Assessment of Metals in Freshwater Environments: A Historical Review","volume":"39","author":"Adams","year":"2020","journal-title":"Environ. Toxicol. Chem."},{"doi-asserted-by":"crossref","unstructured":"Hong, Y., Zhu, Z., Liao, W., Yan, Z., Feng, C., and Xu, D. (2023). Freshwater Water-Quality Criteria for Chloride and Guidance for the Revision of the Water-Quality Standard in China. Int. J. Environ. Res. Public Health, 20.","key":"ref_6","DOI":"10.3390\/ijerph20042875"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"121415","DOI":"10.1016\/j.jclepro.2020.121415","article-title":"Selective liquid phase micro-extraction of metal chloro-complexes from saline waters using ionic liquids","volume":"262","author":"Pirkwieser","year":"2020","journal-title":"J. Clean. Prod."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"301","DOI":"10.1016\/0039-9140(94)80126-6","article-title":"Discontinuous-flow pontetiometric determination of chloride in a lagre-volume wall-jet cell using an ion-selective electrode based on a silver chloride filme chemically deposited on a silver iodide support","volume":"41","author":"Lexa","year":"1994","journal-title":"Talanta"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"412","DOI":"10.1039\/an9739800412","article-title":"Determination of Chloride in Aqueous Soil Extracts and Water Samples by Means of a Chloride-selective Electrode","volume":"98","author":"Oien","year":"1973","journal-title":"Analyst"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"965","DOI":"10.1016\/j.talanta.2004.08.028","article-title":"Flow injection spectrophotometric method for chloride determination in natural waters using Hg(SCN)2 immobilized in epoxy resin","volume":"65","author":"Silva","year":"2005","journal-title":"Talanta"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1577","DOI":"10.1007\/s00216-009-2745-5","article-title":"Multisyringe flow injection analysis hyphenated with liquid core waveguides for the development of cleaner spectroscopic analytical methods: Improved determination of chloride in waters","volume":"394","author":"Maya","year":"2009","journal-title":"Anal. Bioanal. Chem."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"193","DOI":"10.1016\/j.microc.2012.10.020","article-title":"An environmentally friendly flow-based procedure with photo-induced oxidation for the spectrophotometric determination of chloride in urine and waters","volume":"108","author":"Rocha","year":"2013","journal-title":"Microchem. J."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.aca.2019.02.048","article-title":"Instrument-free argentometric determination of chloride via trapezoidal distance-based microfluidic paper devices","volume":"1063","author":"Rahbar","year":"2019","journal-title":"Anal. Chim. Acta"},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/S0039-9140(99)00103-4","article-title":"Determination of Chloride in Drinking and Ground Water by Alcl Molecular Absorption Spectrometry Using Graphite Furnace Atomic Absorption Spectrometer","volume":"50","author":"Parvinen","year":"1999","journal-title":"Talanta"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"663","DOI":"10.1016\/j.talanta.2006.11.036","article-title":"An improved flow system for chloride determination in natural waters exploiting solid-phase reactor and long pathlength spectrophotometry","volume":"72","author":"Marcolino","year":"2007","journal-title":"Talanta"},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"1186","DOI":"10.1016\/j.talanta.2007.01.010","article-title":"Use of tetramethylbenzidine for the spectrophotometric sequential injection determination of free chlorine in waters","volume":"72","author":"Mesquita","year":"2007","journal-title":"Talanta"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"7861","DOI":"10.1007\/s00216-020-02918-9","article-title":"3,3\u2032,5,5\u2032-tetramethylbenzidine as multi-colorimetric indicator of chlorine in water in line with health guideline values","volume":"412","author":"Palladino","year":"2020","journal-title":"Anal. Bioanal. Chem."},{"doi-asserted-by":"crossref","unstructured":"Zhang, Z., Zhao, W., Hu, C., Cao, Y., Liu, Y., and Liu, Q. (2021). A Convenient and Label-Free Colorimetric Detection for L-Histidine Based on Inhibition of Oxidation of 3,3\u2032,5,5\u2032-Tetramethylbenzidine-H2O2 System Triggered by Copper Ions. Front. Chem., 9.","key":"ref_18","DOI":"10.3389\/fchem.2021.773519"},{"unstructured":"World Health Organization (2022). Guidelines for Drinking-Water Quality: Fourth Edition Incorporating the First and Second Addenda, World Health Organization.","key":"ref_19"},{"unstructured":"European Protection Agency (1998). Ambient Water Quality Value for Protection of Sources of Potable Water: Nitrite.","key":"ref_20"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"1699","DOI":"10.1351\/pac199567101699","article-title":"Nomenclature in evaluation of analytical methods including detection and quantification capabilities (IUPAC Recommendations 1995)","volume":"67","author":"Currie","year":"1995","journal-title":"Pure Appl. Chem."},{"unstructured":"Miller, J.N., and Miller, J.C. (2010). Statistics and Chemometrics for Analytical Chemistry, Prentice Hall. [6th ed.].","key":"ref_22"}],"container-title":["Chemosensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2227-9040\/13\/4\/124\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,9]],"date-time":"2025-10-09T17:08:33Z","timestamp":1760029713000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2227-9040\/13\/4\/124"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,4,2]]},"references-count":22,"journal-issue":{"issue":"4","published-online":{"date-parts":[[2025,4]]}},"alternative-id":["chemosensors13040124"],"URL":"https:\/\/doi.org\/10.3390\/chemosensors13040124","relation":{},"ISSN":["2227-9040"],"issn-type":[{"type":"electronic","value":"2227-9040"}],"subject":[],"published":{"date-parts":[[2025,4,2]]}}}