Ahmed A. Abdel Gaber

Novel mercury (II) ion-selective polymeric membrane sensor based on ethyl-2-benzoyl-2-phenylcarbamoyl acetate.

Mercury (II) ion-selective PVC membrane sensor based on ethyl-2-benzoyl-2-phenylcarbamoyl acetate (EBPCA) as a novel nitrogen containing sensing material is successfully developed. The sensor exhibits good linear response of 30 mV per decade within the concentration range 10(-6)-10(-3) mol l(-1) Hg(II). The sensor shows good selectivity for mercury (II) ion in comparison with alkali, alkaline earth, transition and heavy metal ions. The EBPCA-based sensor is suitable for use with aqueous solutions of pH 2.0-4.5 and exhibits minimal interference by Ag(I) and Fe(III), which are known to interfere with other previously suggested sensors. The nature and composition of the sensing material and its mercury complex are examined using Fourier-transform infrared analysis, elemental analysis and X-ray fluorescence techniques. The proposed sensor is applied as a sensor for the determination of Hg(II) content in some amalgam alloys. The results show good correlation with data obtained by atomic absorption spectrometric method.

Novel Sm(III) ion-Selective polymeric membrane sensor based on spiro[oxirane-pyrazolidinedione] derivative ionophore

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.

A Novel Hg(II) PVC Membrane Sensor Based on Simple Ionophore Ethylenediamine Bis‐Thiophenecarboxaldehyde

Abstract A mercury (II) ion‐selective polyvinyl chloride (PVC) membrane sensor based on ethylenediamine bisthiophenecarboxaldehyde (EDBT) as a novel nitrogen‐ and sulfur‐containing sensing material was successfully developed. The ionophore was produced through Schiffs base formation between ethylenediamine and 2‐thiophenecarboxaldehyde. These two reagents have the advantages of low cost and simple chemical compounds. Ortho‐nitro phenyl pentyl ether (o‐NPPE) as solvent and sodium tetraphenyl borate (NaTPB) as a lipophilic salt were chosen. The sensor exhibited a good linear response of 30.0±0.4 mV per decade within the concentration range of 10−7–10−2 and a detection limit of 7.0×10−8 mol L−1 Hg(II). The sensor showed good selectivity and fast response for the mercury (II) ion with respect to some alkali, alkaline earth, transition, and heavy metal ions. The EDBT–based sensor was suitable for aqueous solutions of pH range from 2.0 to 4.5. It can be used for about 3 months without any considerable divergence in potential. The formation constant of ionophore complex with Hg(II) ion was calculated by using the segmented sandwich membrane method. The structure of both the ionophore and its Hg(II) complex were examined using infrared spectra and elemental analysis. The proposed sensor was applied for the determination of Hg(II) content in some dental amulgum alloys and as an indicator electrode for potentiometric titration of Hg(II) ion with EDTA solution, as well as with I−, OH−, and IO3 − ions. In addition, the solubility products of the previous ions were determined by using this sensor.

A Novel PVC Membrane Sensor for Selective Determination of Cerium(III) Ions

Abstract A PVC membrane of azomethine of piperonylidine-4-[2.2]paracyclophanylamine reveals a Nernstian potentiometric response (with slope of 19.3 ± 0.3 mV/decade) for Ce(III) over a wide concentration range (10−1−2.5 × 10−5 mol L−1). The potential of this electrode is independent of pH in the range of 4.5–8.0. It has a fast response time of 30 s and can be used for a period of two months with good reproducibility. The detection limit of this membrane electrode is 1.2 × 10−5 mol L−1. The nature of the azomethine compound and its cerium(III) complex is examined using Fourier-transform infrared analysis, elemental analysis, and X-ray fluorescence techniques. This sensor exhibits a very good selectivities for Ce(III) over a wide variety of metal ions. The proposed sensor has been used as an indicator electrode in the potentiometric titration of carbonate and oxalate ions and in determination of acetyl salicylate content in some drugs.

Divalent transition metal ion mixed ligand complexes with aliphatic dicarboxylic acids and imidazoles

SummaryMixed ligand metal complexes of CoII, NiII and CuII with dicarboxylic aliphatic acids, H2L (succinic, malic and tartaric) as primary ligands and with imidazoles, L′ (imidazole and 2-methylimidazole) as secondary ligands were prepared and characterized. MLL′2 and ML′4 molecular formulae were suggested for these complexes were Formation constants of the different complexes were determined pH-metrically at T = 25 ± 0.1°C and μ = 0.1 mol dm−3 (NaClO4). The stability of the mixed ligand complexes increased as the effective basicity of the dicarboxylic aliphatic acid anion increased, namely, tartarate < malate < succinate acid.