Bismetalloporphyrin-based ISE sensitive to fluoroborate

Abstract

Several μ-oxo-bismetalloporphyrin complexes were synthesized for preparing fluoroborate sensors. The electrode based on μ-oxo-bis[tetra(p-chlorophenyl)porphinatomanganese(III )] with an optimized membrane composition shows a potentiometric response towards fluoroborate ion over the concentration range from 4.3 × 10⁻⁷ to 1.0 × 10⁻¹ mol l⁻¹ with a Nernstian slope, a wide working pH range from 5.5 to 12.0 and a fast response time of 30 s. The electrode shows anti-Hofmeister selectivity towards BF₄⁻ with respect to common co-existing ions, which is an improvement over methods reported so far. As electroactive materials, several μ-oxo-bismetalloporphyrins with different substituents on the benzene rings were compared for potentiometric response characteristics. The interaction between BF₄⁻ and bismetalloporphyrin was investigated using UV/VIS spectrophotometry. The electrode was applied to the determination of fluoroborate in electroplating solutions.