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.

Although surfactants and particles are often used together in stabilization of aqueous emulsions, the contribution of each species to such stabilization at the oil-water interface is poorly understood. The situation becomes more complicated if we consider the nonaqueous oil-oil interface, i.e, the stabilization of nonaqueous oil-in-oil (o/o) emulsions by solid particles and reactive surfactants which, to our knowledge, has not been studied before. We have prepared Pickering nonaqueous simple (o/o) emulsions stabilized by a combination of kaolinite particles and a nonionic polymerizable surfactant Noigen RN10 (polyoxyethylene alkylphenyl ether). Different pairs of immiscible oils were used which gave different emulsion stabilities. Using kaolinite with equal volumes of paraffin oil/formamide system gave no stable emulsions at all concentrations while the addition of Noigen RN10 enhanced the emulsion stability. In contrast, addition of Noigen RN10 surfactant to silicon oil-in-glycerin emulsions stabilized by kaolinite resulted in destabilization of the system at all concentrations. For all systems studied here, no phase inversion in simple emulsion was observed by altering the volume fraction of the dispersed phase as compared to the known water-based simple Pickering emulsions.