Exploiting pi-acceptors for the determination of thyroid hormones (T3 and T4) using a single interface flow system

• Tipo: Artigo em Revista Científica Internacional
• Data: 2009

Autores

Cristina I C Silvestre (Autor) Outra; Joao L M Santos (Autor) FFUP; Jose L F C Lima (Autor) FFUP; Elias A G Zagatto (Autor) Outra

Revista

Título: Talanta

Vol. 79 Nº 4

Páginas: 1177-1180

ISSN: 0039-9140

Editora: Elsevier

Indexação

ISI Web of Knowledge - 4 Citações

Scopus - 3 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Química

Outras Informações

ID Authenticus: P-003-FSN

DOI: 10.1016/j.talanta.2009.01.043

Abstract (EN): A fully automated methodology was developed for the determination of the thyroid hormones levothyroxine (T4) and liothyronine (T3). The proposed method exploits the formation of highly coloured charge-transfer (CT) complexes between these compounds, acting as electron donors, and pi-acceptors such as chloranilic acid (CIA) and 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ). For automation of the analytical procedure a simple, fast and versatile single interface flow system (SIFA)was implemented guaranteeing a simplified performance optimisation, low maintenance and a cost-effective operation. Moreover, the single reaction interface assured a convenient and straightforward approach for implementing job's method of continuous variations used to establish the stoichiometry of the formed CT complexes. Linear calibration plots for levothyroxine and liothyronine concentrations ranging from 5.0 x 10(-5) to 2.5 x 10(-4) mol L(-1) and 1.0 x 10(-5) to 1.0 x 10(-4) mol L(-1), respectively, were obtained, with good precision (R.S.D. <4.6% and <3.9%) and with a determination frequency of 26 h(-1) for both drugs. The results obtained for pharmaceutical formulations were statistically comparable to the declared hormone amount with relative deviations lower than 2.1%. The accuracy was confirmed by carrying out recovery studies, which furnished recovery values ranging from 96.3% to 103.7% for levothyroxine and 100.1% for liothyronine.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 4