125965 20241125101136.0 doi 10.1007/s00604-023-05698-y sideral 133474 ART-2023-133474 eng Camacho-Aguayo, J. Universidad de Zaragoza (orcid)0000-0003-1654-3803 In situ enzymatic generation of Au/Pt nanoparticles as an analytical photometric system: proof of concept determination of tyramine 2023 Access copy available to the general public Unrestricted In situ enzymatic generation of bimetallic nanoparticles, mainly Au/Pt, overcomes the drawbacks (continuous absorbance drift, modest LOQ, and long-time reaction) observed when AuNP alone are produced. In this study, Au/Pt nanoparticles have been characterized by EDS, XPS, and HRTEM images using the enzymatic determination of tyramine with tyramine oxidase (TAO) as a model. Under experimental conditions, the Au/Pt NPs show an absorption maximum at 580 nm which can be related to the concentration of tyramine in the range 1.0 × 10-6M to 2.5 × 10-4M with a RSD of 3.4% (n = 5, using 5 × 10-6M tyramine). The Au/Pt system enables low LOQ (1.0 × 10−6 M), high reduction of the absorbance drift, and a significant shortening of the reaction time (i.e., from 30 to 2 min for a [tyramine] = 1 × 10−4M); additionally, a better selectivity is also obtained. The method has been applied to tyramine determination in cured cheese and no significant differences were obtained compared to a reference method (HRP:TMB). The effect of Pt(II) seems to involve the previous reduction of Au(III) to Au(I) and NP generation from this oxidation state. Finally, a three-step (nucleation-growth-aggregation) kinetic model for the generation of NPs is proposed; this has enabled us to obtain a mathematical equation which explains the experimentally observed variation of the absorbance with time. info:eu-repo/grantAgreement/ES/DGA/E25-20R info:eu-repo/grantAgreement/ES/MICINN/PID2019-105408GB-I00 info:eu-repo/semantics/openAccess by http://creativecommons.org/licenses/by/3.0/es/ 5.4 2023 CHEMISTRY, ANALYTICAL 15 / 106 = 0.142 2023 Q1 T1 0.848 2023 Analytical Chemistry 2023 Q1 9.8 2023 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion Marcos, S. de Universidad de Zaragoza (orcid)0000-0002-7902-6005 Felices, C. Galbán, J. Universidad de Zaragoza (orcid)0000-0002-8973-5104 2009 750 Universidad de Zaragoza Dpto. Química Analítica Área Química Analítica 190, 4 (2023), 114 [9 pp.] Mikrochim. acta Microchimica Acta 0026-3672 807468 http://zaguan.unizar.es/record/125965/files/texto_completo.pdf Versión publicada 2439603 http://zaguan.unizar.es/record/125965/files/texto_completo.jpg?subformat=icon icon Versión publicada oai:zaguan.unizar.es:125965 articulos driver 2024-11-22-12:00:52 ARTICLE