Based on international standard procedures, the degree of unsaturation on biodiesel was evaluated, called iodine value. Two titration techniques were used to determine the iodine value: colorimetric and potentiometric techniques. The uncertainty of measurement was used to evaluate the quality of the results. The potentiometric technique showed better quality in the determination of the iodine v...

A first step towards a microfabricated potentiometric thin-film sensor array for the simultaneous detection of Pb, Cd and Cu has been realized. The sensitive layers used are on the basis of chalcogenide glass materials. These thin-film chalcogenide glass materials that consist of mixtures of Pb-Ag-As-I-S, Cd-Ag-As-I-S or Cu-Ag-As-Se have been prepared by pulsed laser deposition technique. The d...

In the previous communication (l), it was shown that the free energy of the bivalent fumarate ion at 25” is -144,630 calories. In the present communication the measurement of the equilibrium at 25” between fumaric acid and malic acid in the presence of fumarase is reported, and from the values obtained computations are made of the free energy and heat of formation of the bivalent I-malate ion a...

The highly enantioselective molecular recognition of the malate dianion by a synthetic receptor in aqueous solution has been studied by potentiometric titrations, mass spectrometry (ESI-MS), diffusion measurements (PGSE NMR) and molecular modeling.

in this work, the results concerning to the mean activity coefficient measurements for nacl in the (glycerol + water) system using the potentiometric method are reported. the potentiometric measurements were performed on the galvanic cells without liquid junction of the type: ag|agcl|nacl (m), glycerol (wt%), h2o (1 - wt)%|na-ise, in various mixed solvent systems containing 0, 5, 10, 20 and 30 ...

A new approach to potentiometric sensing utilizing paper-based microfluidic sampling is studied in this work. A solid-contact ion-selective electrode and a solid-contact reference electrode are pressed against a filter paper into which the sample solution is absorbed. The filter paper acts simultaneously as a sampling unit and as a sample container during potentiometric sensing. The paper subst...

In this work, the results relating to the mean activity coefficient measurements for ionic liquid of 1- propyl -3 methylimidazolium bromide, [PMIm]Br in ethanol+ water mixtures have been reported using potentiometric measurements at T=( 298.2, 308.2 and 318.2)K. The electromotive force (emf) measurements were performed on the galvanic cell of the type:Br-ISE│[PrMIm] (m) ethanol (wt.%), H2O (1−w...

in this research complexation of dioxovanadium(v) with nitrilotriacetic acid (nta) at differentionic strengths (0.1 to 1.0 mol dm-3) of sodium perchlorate as supporting electrolyte and ph rangeof 1.00-2.50 at 25 °c has been investigated by a combination of potentiometric and uvspectrophotometric measurements. stability constants of two species, v0211l- and vo2h2l havebeen calculated. ionic stre...