Abstract
A poly vinyl chloride (PVC) membrane sensor for Sm(III) ions based on [1-phenyl-3′(2-nitrophenyl) spiro[Oxirane-2.4-Pyrazoline]-3,5-dione] (PNSOP) as a membrane carrier was developed. This sensor exhibits a rapid and good Nernstian response towards Sm(III) ions in the range of 10
−1
to 10
−6
mol l
−1
with a slope of 19.3±0.2 mV per decade and a detection limit of 6.1×10
−7
mol l
−1
. The sensor response and selectivity remained almost unchanged for at least 4 months. It has a fast response time about of 5 s. The sensor can be used in a pH range from 4.0 to 8.2 and demonstrates good discriminating power over a wide variety of other metal ions. The formation constant of ionophore complex with Sm(III) was calculated by using the segmented sandwich membrane method. The nature of the PNSOP ionophore and its Sm(III) complex is examined using Fourier-transform infrared analysis and elemental analysis technique. The proposed sensor was successfully applied as an indicator electrode in potentiometric titration of oxalate and carbonate ions and determination of acetylsalicylate and carbonate ions in some drugs.