Praseodymium analysis in aqueous solution by Pr~(3+)-PVC membrane sensor based on N,N'-bis (4-hydroxysalicylidene) -1-3-phenylenediamine

摘要

A new Pr~(3+) poly vinyl chloride PVC membrane sensor based on a membrane containing 3% N,N'-bis(4-hydroxysalicylidene)-l-3-phenylenediamine (HSPDA) as an ionophore, 2% sodium tetraphenyl borate (NaTPB) as an anionic additive, 65% benzyl acetate (BA) as solvent mediator and 30% poly(vinyl chloride) was prepared. This sensor responds to praseodymium ion in a wide linear dynamic range of 1.0 ×l0~(-6) to 1.0 × 10~(-2) mol L~(-1) with Nernstian slope of 19.8 ± 0.4 mV per decade and a detection limit of 5.7 × 10~(-7) mol L~(-1) in pH range of 3.1 to 9.8. It has a fast response time of ~5 s in the whole concentration range, and can be used for at least 2 months without any considerable divergences in the potentials. The proposed sensor displays an excellent selectivity for Pr~(3+) ions with respect to a large number of alkali, alkaline earth, transition and heavy metal ions. The developed sensor was successfully applied as an indicator electrode in Pr~(3+) ion potentiometric titration with EDTA, and in direct determination of fluoride ion in two mouth wash samples.