Construction of Tm3+-PVC membrane sensor based on 1-(2-thiazolylazo)-2-naphthol as sensing material

In this study, a new thulium(III) membrane sensor was constructed. The proposed membrane sensor was fabricated based on a membrane containing 2% sodium tetraphenyl borate (NaTPB) as an anionic additive, 65% benzyl acetate (BA) as solvent mediator, 3% 1-(2-thiazolylazo)-2-naphthol (TN) as ionophore, and 30% poly(vinyl chloride) (PVC). The proposed Tm3+ electrode exhibits a Nernstian response of 19.5 ± 0.2 mV per decade of thulium concentration, and has a lower detection limit of 8.7 × 10− 7 mol L− 1. The linear range of the sensors was 1.0 × 10− 6 to 1.0 × 10− 2 mol L− 1. It works well in the pH range of 3.2–9.5. Moreover, the recommended selective sensor revealed a comparatively satisfactory selectivity regarding most of the alkali, alkaline earth, some transition and heavy metal ions. The membrane sensor was applied to the determination of fluoride ions in mouth wash samples.