{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,1,16]],"date-time":"2026-01-16T01:14:47Z","timestamp":1768526087940,"version":"3.49.0"},"reference-count":21,"publisher":"MDPI AG","issue":"6","license":[{"start":{"date-parts":[[2024,3,19]],"date-time":"2024-03-19T00:00:00Z","timestamp":1710806400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Interreg EMR Food_Screening project","award":["EMR159"],"award-info":[{"award-number":["EMR159"]}]},{"name":"Interreg Euregio Meuse-Rhin","award":["EMR159"],"award-info":[{"award-number":["EMR159"]}]},{"name":"Walloon Region of Belgium","award":["EMR159"],"award-info":[{"award-number":["EMR159"]}]},{"name":"Ministerie van Economische Zaken en Klimaat","award":["EMR159"],"award-info":[{"award-number":["EMR159"]}]},{"name":"Provincie Limburg","award":["EMR159"],"award-info":[{"award-number":["EMR159"]}]},{"name":"Die Landesregierung Nordrhein-Westfalen","award":["EMR159"],"award-info":[{"award-number":["EMR159"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Colorimetric characterisation systems based on LEDs and RBG sensors are straightforward to implement, are highly integrable allowing for portable measurement systems and can be constructed using widespread and affordable components. They have already proved to be a satisfactory solution in several applications related to chemical analysis. In this paper, we present an RGB sensor-based prototype for colorimetric characterisation, which can accommodate cuvettes with optical paths of 10 mm and 40 mm. We assessed the impact of experimental condition parameters such as the variability of the analyte volume in the cuvette, as well as the presence of floating particles or deposits at the bottom of the cuvette. While these would not impact the result given by a spectrophotometer that generally has a directional light source, they must be considered in LED\/RGB sensor analysers in which the light path is not tightly controlled. We demonstrated that there is a minimal sensor height above the bottom of the cuvette and a minimal analyte level (both depending on the prototype optical path length) above which the analyte volume and the presence of floating particles and deposits have no impact on the prototype output signal. Finally, based on these results, we proposed a test method for a quick dye-displacement assay, in which the reagent is a dye-loaded molecularly imprinted polymer that is poured directly into a cuvette.<\/jats:p>","DOI":"10.3390\/s24061960","type":"journal-article","created":{"date-parts":[[2024,3,20]],"date-time":"2024-03-20T05:04:12Z","timestamp":1710911052000},"page":"1960","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":2,"title":["Design Aspects for Portable LED-Based Colorimetric Characterisation Systems Targeting Liquid Analytes"],"prefix":"10.3390","volume":"24","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-2939-4694","authenticated-orcid":false,"given":"Fran\u00e7ois","family":"Dupont","sequence":"first","affiliation":[{"name":"Microsys Laboratory, Department of Electrical Engineering and Computer Science, University of Li\u00e8ge, 4000 Li\u00e8ge, Belgium"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5060-4086","authenticated-orcid":false,"given":"Serguei","family":"Stoukatch","sequence":"additional","affiliation":[{"name":"Microsys Laboratory, Department of Electrical Engineering and Computer Science, University of Li\u00e8ge, 4000 Li\u00e8ge, Belgium"}]},{"given":"Philippe","family":"Laurent","sequence":"additional","affiliation":[{"name":"Microsys Laboratory, Department of Electrical Engineering and Computer Science, University of Li\u00e8ge, 4000 Li\u00e8ge, Belgium"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0214-1320","authenticated-orcid":false,"given":"Kasper","family":"Eersels","sequence":"additional","affiliation":[{"name":"Sensor Engineering Department, Faculty of Science and Engineering, Maastricht University, 6200 MD Maastricht, The Netherlands"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6939-0866","authenticated-orcid":false,"given":"Bart","family":"van Grinsven","sequence":"additional","affiliation":[{"name":"Sensor Engineering Department, Faculty of Science and Engineering, Maastricht University, 6200 MD Maastricht, The Netherlands"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-9612-4312","authenticated-orcid":false,"given":"Jean-Michel","family":"Redout\u00e9","sequence":"additional","affiliation":[{"name":"Microsys Laboratory, Department of Electrical Engineering and Computer Science, University of Li\u00e8ge, 4000 Li\u00e8ge, Belgium"}]}],"member":"1968","published-online":{"date-parts":[[2024,3,19]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"187","DOI":"10.1016\/j.aca.2020.07.030","article-title":"Novel approaches for colorimetric measurements in analytical chemistry\u2014A review","volume":"1135","author":"Fernandes","year":"2020","journal-title":"Anal. 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Proceedings of the 2018 IEEE SENSORS, New Delhi, India.","DOI":"10.1109\/ICSENS.2018.8589708"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"123244","DOI":"10.1016\/j.talanta.2022.123244","article-title":"RGB color sensor for colorimetric determinations: Evaluation and quantitative analysis of colored liquid samples","volume":"241","author":"Machado","year":"2022","journal-title":"Talanta"},{"key":"ref_5","doi-asserted-by":"crossref","unstructured":"Danh, L.V.Q., Thien, D.C., Binh, Q.D., Dieu, N.T., and Hoan, T.N.K. (2021, January 23\u201325). A Low-Cost Colorimetric Sensor for On-Site Automatic Monitoring of Nitrite in Aquaculture. Proceedings of the 2021 IEEE 7th International Conference on Smart Instrumentation, Measurement and Applications (ICSIMA), Bandung, Indonesia.","DOI":"10.1109\/ICSIMA50015.2021.9526324"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"108138","DOI":"10.1016\/j.microc.2022.108138","article-title":"A palm-sized wireless device for colorimetric nitrite determination in water","volume":"183","author":"Cadeado","year":"2022","journal-title":"Microchem. J."},{"key":"ref_7","doi-asserted-by":"crossref","unstructured":"Debarshi, S., and Khan, M.M. (2019, January 8\u201310). Portable and low-cost LED based Spectrophotometer for the Detection of Nitrite in simulated-Urine. Proceedings of the 2019 International Conference on Electrical, Electronics and Computer Engineering (UPCON), Aligarh, India.","DOI":"10.1109\/UPCON47278.2019.8980097"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"700","DOI":"10.3807\/JOSK.2015.19.6.700","article-title":"An array-Type RGB Sensor for Precision Measurement of pH","volume":"19","author":"Kim","year":"2015","journal-title":"J. Opt. Soc. Korea"},{"key":"ref_9","doi-asserted-by":"crossref","unstructured":"Stoukatch, S., Debliquy, M., Dupont, F., and Redout\u00e9, J.M. (2023). Low-Cost Optical pH Sensor with a Polyaniline (PANI)-Sensitive Layer Based on Commercial off-the-Shelf (COTS) Components. Micromachines, 14.","DOI":"10.3390\/mi14122197"},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"128","DOI":"10.1016\/j.measurement.2015.02.049","article-title":"Turbidimeter and RGB sensor for remote measurements in an aquatic medium","volume":"68","author":"Sampedro","year":"2015","journal-title":"Measurement"},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"792","DOI":"10.1016\/j.talanta.2007.12.014","article-title":"An inexpensive, portable and microcontrolled near infrared LED-photometer for screening analysis of gasoline","volume":"75","year":"2008","journal-title":"Talanta"},{"key":"ref_12","unstructured":"(2023, October 02). \u201cColor Analysis for Pharmaceutical Products Using UV-Visible Absorption Technique\u201d, App. Note, Thermo Scientific. Available online: https:\/\/assets.thermofisher.com\/TFS-Assets\/MSD\/Application-Notes\/color-analysis-pharmaceutical-an56364-en.pdf."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"900","DOI":"10.1039\/C7AY02644G","article-title":"A novel multicommuted flow analysis strategy for the spectrophotometric determination of cadmium in water at \u00b5g L-1 levels without using a preconcentration step","volume":"10","author":"Reis","year":"2018","journal-title":"Anal. Methods"},{"key":"ref_14","unstructured":"(2024, March 08). VLMW33S2V1-5K8L-08 Datasheet. Available online: https:\/\/www.vishay.com\/docs\/81273\/vlmw33.pdf."},{"key":"ref_15","unstructured":"(2024, March 08). VEML3328 Application Note. Available online: https:\/\/www.vishay.com\/docs\/80010\/designingveml3328.pdf."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"811","DOI":"10.1080\/09500340.2015.1007103","article-title":"High-index dielectric substrates with nearly constant reflectance for incident unpolarized or circularly polarized light over a wide range of incidence angles","volume":"62","author":"Azzam","year":"2015","journal-title":"J. Mod. Opt."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"8710","DOI":"10.1364\/AO.36.008710","article-title":"Absorption spectrum (380\u2013700 nm) of pure water, I.I. Integrating cavity measurements","volume":"36","author":"Pope","year":"1997","journal-title":"Appl. Opt."},{"key":"ref_18","doi-asserted-by":"crossref","unstructured":"Martinez Gache, S.A., Recoulat Angelini, A.A., Sabeckis, M.L., and Gonzales Flecha, F.L. (2020). Improving the stability of the malachite green method for determination of phosphate using Pluronic P68. Anal. Biochem., 597.","DOI":"10.1016\/j.ab.2020.113681"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1016\/0143-7208(95)00067-4","article-title":"Photostability of crystal violet (CI 42555)","volume":"30","author":"Denman","year":"1996","journal-title":"Dye. Pigment."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"748","DOI":"10.2146\/ajhp050438","article-title":"Accuracy and reproducibility of small-volume injections from various-sized syringes","volume":"63","author":"Erstad","year":"2006","journal-title":"Am. J. Health-Syst. Pharm."},{"key":"ref_21","first-page":"9511209","article-title":"Design of a Lab-on-Chip Cartridge for the Optical Detection of Small Molecules Based on Dye-Displacement MIPs","volume":"72","author":"Goosens","year":"2023","journal-title":"IEEE Trans. Instrum. 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