{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,1]],"date-time":"2026-04-01T18:51:14Z","timestamp":1775069474221,"version":"3.50.1"},"reference-count":79,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2023,8,25]],"date-time":"2023-08-25T00:00:00Z","timestamp":1692921600000},"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>This paper presents the development of cheap and selective Paper-based Analytical Devices (PADs) for selective Pd(II) determination from very acidic aqueous solutions. The PADs were obtained by impregnating two cm-side squares of filter paper with an azoic ligand, (2-(tetrazolylazo)-1,8 dihydroxy naphthalene-3,6,-disulphonic acid), termed TazoC. The so-obtained orange TazoC-PADs interact quickly with Pd(II) in aqueous solutions by forming a complex purple-blue-colored already at pH lower than 2. The dye complexes no other metal ions at such an acidic media, making TazoC-PADs highly selective to Pd(II) detection. Besides, at higher pH values, other cations, for example, Cu(II) and Ni(II), can interact with TazoC through the formation of stable and pink-magenta-colored complexes; however, it is possible to quantify Pd(II) in the presence of other cations using a multivariate approach. To this end, UV-vis spectra of the TazoC-PADs after equilibration with the metal ions solutions were registered in the 300\u2013800 nm wavelength range. By applying Partial Least Square regression (PLS), the whole UV-vis spectra of the TazoC-PADs were related to the Pd(II) concentrations both when present alone in solution and also in the presence of Cu(II) and Ni(II). Tailored PLS models obtained with matrix-matched standard solutions correctly predicted Pd(II) concentrations in unknown samples and tap water spiked with the metal cation, making the method promising for quick and economical sensing of Pd(II).<\/jats:p>","DOI":"10.3390\/s23177425","type":"journal-article","created":{"date-parts":[[2023,8,25]],"date-time":"2023-08-25T08:42:20Z","timestamp":1692952940000},"page":"7425","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":5,"title":["Colorimetric Paper-Based Analytical Devices (PADs) Backed by Chemometrics for Pd(II) Detection"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4106-2219","authenticated-orcid":false,"given":"Giancarla","family":"Alberti","sequence":"first","affiliation":[{"name":"Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-4484-4788","authenticated-orcid":false,"given":"Lisa Rita","family":"Magnaghi","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy"},{"name":"Unit\u00e0 di Ricerca di Pavia, Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Via G. Giusti 9, 50121 Firenze, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Marzia","family":"Iurato","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Camilla","family":"Zanoni","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Raffaela","family":"Biesuz","sequence":"additional","affiliation":[{"name":"Department of Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy"},{"name":"Unit\u00e0 di Ricerca di Pavia, Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (INSTM), Via G. Giusti 9, 50121 Firenze, Italy"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2023,8,25]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"36","DOI":"10.1038\/s41545-021-00127-0","article-title":"Removal of heavy metal ions from wastewater: A comprehensive and critical review","volume":"4","author":"Qasem","year":"2021","journal-title":"NPJ Clean Water"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"112879","DOI":"10.1016\/j.sna.2021.112879","article-title":"Development of semiconductor based heavy metal ion sensors for water analysis: A review","volume":"330","author":"Nigam","year":"2021","journal-title":"Sens. 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