2026-04-27T13:13:30Zhttps://riubu.ubu.es/oai/request

oai:riubu.ubu.es:10259/43792022-04-29T12:02:47Zcom_10259_4376com_10259_5086com_10259_2604col_10259_4377

Alvarado Gámez, Ana Lorena Alonso Lomillo, Mª Asunción Domínguez Renedo, Olga Arcos Martínez, Julia alkaline phosphatase chronoamperometry 2-phospho-L-ascorbic acid trisodium salt screen printed carbon electrode tungsten This paper presents a chronoamperometric method to determine tungsten in water using screen-printed carbon electrodes modified with gold nanoparticles and cross linked alkaline phosphatase immobilized in the working electrode. Enzymatic activity over 2-phospho-L-ascorbic acid trisodium salt, used as substrate, was affected by tungsten ions, which resulted in a decrease of chronoamperometric current, when a potential of 200 mV was applied on 10 mM of substrate in a Tris HCl buffer pH 8.00 and 0.36 M of KCl. Calibration curves for the electrochemical method validation, give a reproducibility of 5.2% (n = 3), a repeatability of 9.4% (n = 3) and a detection limit of 0.29 ± 0.01 μM. Enriched tap water, purified laboratory water and bottled drinking water, with a certified tungsten reference solution traceable to NIST, gave a recovery of 97.1%, 99.1% and 99.1% respectively (n = 4 in each case) and a dynamic range from 0.6 to 30 μM. This study was performed by means of a Lineweaver–Burk plot, showing a mixed kinetic inhibition. 2017-03-17 2017-03-17 2015-02 info:eu-repo/semantics/article http://hdl.handle.net/10259/4379 eng Sensors, 2015, V. 15, n. 2, p. 2232-2243 http://dx.doi.org/10.3390/s150202232 http://creativecommons.org/licenses/by/4.0/ info:eu-repo/semantics/openAccess Attribution 4.0 International MDPI