Vitamin B₁ Sensitive Poly(vinyl chloride) Membrane Electrode Based on Hydrophobic Tetraphenylborate Derivatives and Their Application

A vitamin B₁ sensitive poly(vinyl chloride) membrane electrode based on hydrophobic tetraphenyiborate derivatives is described. The sensing membrane contains an ion pair of vitamin B₁-tetrakis[3, 5-bis(2-methoxyhexafluoro-2-propyl)-phenyl] borate (HFPB) or -tetrakis[3, 5-bis(trifluoromethyl)-phenyl] borate (TFPB) as a novel electroactive component, and it is plasticized with o-nitrophenyl octyl ether. The electrodes based on HFPB and TFPB exhibit Nernstian response down to 10^−7.5 and 10⁻⁷ M vitamin B₁ at pH 4, respectively. Response time is 5–10s for Increasing concentrations of sample solutions. Interferences from common Inorganic cations, some organic acids, and conventional dopes in oral solutions are negligible. The vitamin B₁ electrode is successfully applied to the determination of vitamin B₁ contents In an oral solution for both batch and flow infection systems. The results show good correlation with those obtained by conventional HPLC-UV detection with a coefficient of correlation of 0.99.