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We investigated the properties of 1-decyl-3-methylimidazolium bromide (DMImBr), a molten salt at room temperature, and its mixtures with water in the whole proportions.At low concentrations, this salt behaved like a classical cationic amphiphile. Its critical micellar concentration (cmc) was determined by conductimetry and by measuring electromotive forces (EMF) with bromide or cationic surfactant-selective...
The characteristics, performance, and application of an electrode, namely, Pt|Hg|Hg 2 (PABzt) 2 | graphite, where PABzt stands for p-aminobenzoate ion, are described. This electrode responds to PABzt with sensivity of (58.1+/-1.0) mV per decade over the range 1.0x10 -4 to 1.0x10 -1 moll -1 at pH 6.5-8.0 and a detection limit of 3.2x10 - ...
The formation of open chain polyammonium cation-fluoride and -carbonate complexes was studied by potentiometric and calorimetric techniques at t=25 o C. Several species of H i AL (A=amine; L=F - , CO 32- ) are formed in both systems with a mean stability logK=1.0ζ (ζ=|z anion xz cation |) and logK=2...
A new, highly sensitive, fast responding and stable potentiometric biosensor for creatinine determination is developed. The biosensor is based on an ammonium ion-selective electrode. Creatinine deiminase (EC 3.5.4.21) is chemically immobilized on the surface of the polymeric ion-sensitive membrane in the form of monomolecular layer using a simple, one-step carbodiimide covalent attachment method....
This paper describes a potentiometric method for determination of l-histidine (l-his) in aqueous media, using a carbon paste electrode modified with tetra-3,4-pyridinoporphirazinatocopper(II) (Cu (3,4tppa)). The electrode exhibits linear response to the logarithm of the concentration of l-histidine from 2.4 x 10 -5 to 1.0 x 10 -2 M, with a response slope of -49.5 +/- 1mV...
A new PVC membrane potentiometric sensor that is highly selective to Fe(III) ions was prepared by using 2-[(2-hydroxy-1-propenyl-buta-1,3-dienylimino)-methyl]-4-p-tolylazo-phenol [HPDTP] as a suitable carrier. The electrode exhibits a linear response for iron(III) ions over a wide concentration range (3.5 x 10 -6 to 4.0 x 10 -2 ) with a super Nernstian slope of 28.5 (+/-0...
The Wickbold decomposition method in combination with differential potentiometric detection via fluoride ion-selective electrode has been applied to analysis of total fluorine in biological matrices. The performance of the method has been evaluated for determination of total fluorine in rat blood. Total mineralization of the biological sample is achieved by combustion of the sample in oxygen/hydrogen...
The Na + association constants, K 11 and β 12 , of 1/1 and 1/2 stoichiometry of macrocycles of (1,2)dibenzo[15]crown-5, (1,3)dibenzo[18]crown-6, (1,4)dibenzo[21]crown-7, (2,3)dibenzo[21]crown-7, (2,4)dibenzo[24]-crown-8 and dicyclohexano[24]crown-8 were determined in THF/water, (50/50), mixtures. We used a Methrom Na + ISE for the potentiometric measurements...
The possibility of applying natural monocrystaline pyrite as a sensor for the potentiometric titration of weak acids in N,N-dimethylformamide, methylpyrrolidone and pyridine was investigated. The potential of this electrode in N,N-dimethylformamide, methylpyrrolidone and pyridine exhibits a sub-Nernst dependence. In N,N-dimethylformamide the slope (mV/pH) is 39.0 and in methylpyrrolidone it is 45...
Four thiacalix[4]biscrown ethers with 1,3-alternate conformation were examined for the potentiometric responses in poly(vinyl chloride) membrane electrodes. Their potentiometric selectivities toward potassium and cesium ions over other alkali, alkaline earth, and transition metal ions were measured by the fixed interference method (FIM). Among the ionophores, 1,3-alternate thiacalix[4]biscrown-6,6...
Sequential injection with “Lab-at-Valve (LAV)” approach is demonstrated for potentiometric determination of chloride. The LAV flow-through electrode system consists of two Ag/AgCl electrodes: one as a reference electrode, silver chloride activated surface-silver wire soaked in a constant-concentration chloride ion solution in a small tube covered with a polymer-membrane, another as a working electrode...
The feasibility of a newly synthesized Rh(III) complex, Rh[(trpy)(bpy)Cl](PF 6 ) 2 , as a novel ionophore for the preparation of anion-selective polymeric membrane electrodes was tested. The ionophore exhibited anti-Hofmeister behavior with enhanced potentiometric selectivity toward thiocyanate ion compared to other anions. The influence of some experimental parameters such as membrane...
Calculation and reporting procedures are described, which aim to improve the quality and comparability of published formation constant values obtained by glass-electrode potentiometry. Ways in which the processing of data by computer optimization programs can be standardized are the main concern, particularly in respect of improving the usefulness of equilibrium data through incorporation into large...
Four glutathione (GSH)-selective electrodes were developed with different techniques and in different polymeric matrices. Precipitation-based technique with bathophenanthroline–ferrous as cationic exchanger in polyvinyl chloride (PVC) matrix was used for sensor 1 fabrication. β-Cyclodextrin (β-CD)-based technique with either tetrakis(4-chlorophenyl)borate (TpClPB) or bathophenanthroline–ferrous as...
A highly selective poly(vinyl chloride) (PVC) membrane electrode based on butane -2,3-dione bis(salicylhydrazonato) zinc(II) [Zn (BDSH)] complex as carrier for thiocyanate-selective electrode is reported. The influence of membrane composition, pH and possible interfering anions were investigated on the response properties of the electrode. The sensor responds to thiocyanate in linear range from 1...
A new highly Tl(I)-selective PVC membrane electrode based on tetrathia macrocycle 6,7: 14,15-dibenzo-5,8,13,16-tetraoxo-1,4,9,12-tetrathiacyclohexadecane [Bz 2 O 4 (16)aneS 4 ] (I) as membrane carrier, o-nitrophenyloctyl ether (o-NPOE) as solvent mediator and potassium tetrakis(p-chlorophenyl)borate (KTpClPB) as lipophilic additive has been developed. The best performance was...
A chemically modified carbon paste electrode with 3,4-tetra pyridinoporphirazinatocobalt(II) (Co(3,4 tppa) was applied to the determination of free cyanide ion. The electrode has a linear range between 1.5×10 −5 M and 1.0×10 −2 M with a Nernstian slope of 60±1.5mV/decade and its detection limit is 9×10 −6 M. The response time of electrode is 5min. The proposed electrode was...
A novel solid-contact potentiometric sensor for ascorbic acid based on cobalt phthalocyanine nanoparticles (NanoCoPc) as ionophore was fabricated without any need of auxiliary materials (such as membrane matrix, plasticizer, and other additives). The electrode was prepared by simple drop-coating NanoCoPc colloid on the surface of a glassy carbon electrode. A smooth, bright and blue thin film was strongly...
The characteristics, performance, and application of an electrode, namely Pt|Hg|Hg 2 (DCF) 2 |graphite, where DCF stands for diclofenac ion, are described. This electrode responds to diclofenac with sensitivity of (58.1±0.8)mV/decade over the range 5.0×10 −5 to 1.0×10 −2 moll −1 at pH 6.5–9.0 and a detection limit of 3.2×10 −5 moll −1 . The electrode...
The polyamines, octyl-[2-(2-octylamino-ethylamino)-ethyl]-amine (L 1 ) and octyl-{2-[2-(2-octylamino-ethylamino)-ethylamino]-ethyl}-amine (L 2 ), have been used as anion ionophores in PVC-based membrane ion-selective electrodes. Different electrodes were prepared containing L 1 , or L 2 , and o-nitrophenyl octyl ether (NPOE) or bis(2-ethylhexyl)sebacate (DOS) as plasticizers...
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