Simultaneous Potentiometric Determination of Thiamine and Pyridoxine in Multivitamins Using a Single Cyclodextrin-Based Thiamine-Selective Electrode

• Type: Article in International Scientific Journal
• Date: 2009

Authors

Ana Rita Pires (Author) Other; Alberto N Araujo (Author) FFUP; Joao A Lopes (Author) Other; Conceicao C B S M Montenegro (Author) FFUP

Journal

Title: Analytical Letters

Vol. 42 No. 2

Pages: 1923-1939

ISSN: 0003-2719

Publisher: Taylor & Francis

Indexing

ISI Web of Knowledge - 4 Citations

ISI Web of Science

Scopus - 5 Citations

Scientific classification

FOS: Natural sciences > Chemical sciences

CORDIS: Health sciences

Other information

Authenticus ID: P-003-P2M

DOI: 10.1080/00032710903082549

Resumo (PT): In this work, a PVC tubular ion-selective electrode without internal reference [composed of 6.35% (w/w) of β-cyclodextrin as ionophore, 1.59% (w/w) of potassium tetrakis (p-chlorophenyl) borate as lipophilic additive, and 63.5% (w/w) of 2-fluorophenyl-2-nitrophenyl ether as mediator solvent] was used to accomplish the simultaneous determination of thiamine and pyridoxine in multivitamin products. The electrode responds selectively to thiamine but presents high initial diffusion potential contribution from pyridoxine. This fact was exploited under flow conditions for the quantitative assessment of both species. A multitask flow system was optimized to dilute appropriately real samples and prepare in-line the set of calibrating solutions. The potentiometric signal was modeled by partial least squares regression, enabling the prediction of the content of each vitamin in the range of 1 10-3 to 1 10-4 mol L-1. Absolute errors of prediction inferior to 0.06 10-4 mol L-1 and 0.16 10-4 mol L-1 for pyridoxine and thiamine respectively were obtained when compared with the chromatographic method. <br> <br> Keywords: ISE; partial least squares regression; pyridoxine; SIA; thiamine <br> <a target="_blank" href="http://www.informaworld.com/smpp/content~db=all~content=a914772988~frm=titlelink"> Texto integral</a> <br> <br>

Abstract (EN): In this work, a PVC tubular ion-selective electrode without internal reference [composed of 6.35% (w/w) of -cyclodextrin as ionophore, 1.59% (w/w) of potassium tetrakis (p-chlorophenyl) borate as lipophilic additive, and 63.5% (w/w) of 2-fluorophenyl-2-nitrophenyl ether as mediator solvent] was used to accomplish the simultaneous determination of thiamine and pyridoxine in multivitamin products. The electrode responds selectively to thiamine but presents high initial diffusion potential contribution from pyridoxine. This fact was exploited under flow conditions for the quantitative assessment of both species. A multitask flow system was optimized to dilute appropriately real samples and prepare in-line the set of calibrating solutions. The potentiometric signal was modeled by partial least squares regression, enabling the prediction of the content of each vitamin in the range of 1x10-3 to 1x10-4mol L-1. Absolute errors of prediction inferior to 0.06x10-4mol L-1 and 0.16x10-4mol L-1 for pyridoxine and thiamine respectively were obtained when compared with the chromatographic method.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 17