A thionine-based reversible redox sensor in a sequential injection system

• Tipo: Artigo em Revista Científica Internacional
• Data: 2010

Autores

Marieta L C Passos (Autor) Outra; Lucia L M F S Saraiva (Autor) FFUP; Jose L F C Lima (Autor) FFUP

Revista

Título: Analytica Chimica Acta

Vol. 668 Nº 1

Páginas: 41-46

ISSN: 0003-2670

Editora: Elsevier

Indexação

ISI Web of Knowledge - 7 Citações

Scopus - 8 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

CORDIS: Ciências da Saúde

Outras Informações

ID Authenticus: P-003-6NF

DOI: 10.1016/j.aca.2010.01.060

Resumo (PT): Chemistry and regarding the need for lower reagent consumption with improved analytical performance, an automatic methodology with a flow-through optosensor incorporating solid-phase spectrophotometric detection was developed. The sensor used in this work was based on the redox state of thionine whose oxidized form is blue and reduced form is colorless with monitoring carried out at 621 nm. This redox indicator was immobilized on gel beads and subsequently packed into a flow-through cell. It was then assembled into a sequential injection system and was shown to be an excellent alternative to monitor enzymatic redox reactions automatically as the redox catalysis is performed by glucose dehydrogenase. This enzyme is a representative dehydrogenase enzyme and uses NAD+ as cofactor, promoting the oxidation of glucose to glucono-lactone and reduction of NAD+ to NADH. The produced NADH promotes color depletion on the surface of the sensor. The calibration graph for glucose was linear between 5.74 × 10−4 and 2.00 × 10−3 mol L−1 and detection limit was 1.72 × 10−4 mol L−1. Glucose concentration in different samples including sera, salines, perfusion solutions, powder for preparing oral solutions and solutions for hemodialysis was determined. The method proved to be reproducible with a RSD < 5% for glucose determinations. <br> <br> Keywords: Sequential injection analysis; Glucose; Glucose dehydrogenase; Redox sensor; Immobilized thionine; Solid-phase spectrophotometry <br> <a target="_blank" href="http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TF4-4YB5M6D-8&_user=2460038&_coverDate=05%2F23%2F2010&_rdoc=1&_fmt=high&_orig=search&_sort=d&_docanchor=&view=c&_acct=C000057398&_version=1&_urlVersion=0&_userid=2460038&md5=bf38262721aafd7515d128a92a0dfcfd"> Texto integral </a> <br> <br>

Abstract (EN): According to the current demands of Green Analytical Chemistry and regarding the need for lower reagent consumption with improved analytical performance, an automatic methodology with a flow-through optosensor incorporating solid-phase spectrophotometric detection was developed. The sensor used in this work was based on the redox state of thionine whose oxidized form is blue and reduced form is colorless with monitoring carried out at 621 nm. This redox indicator was immobilized on gel beads and subsequently packed into a flow-through cell. It was then assembled into a sequential injection system and was shown to be an excellent alternative to monitor enzymatic redox reactions automatically as the redox catalysis is performed by glucose dehydrogenase. This enzyme is a representative dehydrogenase enzyme and uses NAD as cofactor, promoting the oxidation of glucose to glucono-lactone and reduction of NAD(+) to NADH. The produced NADH promotes color depletion on the surface of the sensor. The calibration graph for glucose was linear between 5.74 x 10(-4) and 2.00 x 10(-3) mol L(-1) and detection limit was 1.72 x 10(-4) mol L(-1). Glucose concentration in different samples including sera, salines, perfusion solutions, powder for preparing oral solutions and solutions for hemoclialysis was determined. The method proved to be reproducible with a RSD <5% for glucose determinations. (C) 2010 Elsevier B.V. All rights reserved.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Notas: autor para correspondência