A direct potentiometric titration method was applied for determination of Ranitidine Hydrochloride. The method is based on the treatment of the primary data with nonlinear regression procedure using commercial software. A general formula valid for every type of acid base titration, derived before is used as a direct input. The acid-base constants of N, N dimethyl-5 [2-(1-methylamine-2-nitroviny...

This contribution describes the practical and computational aspects relevant for the quantitative analysis of chemical equilibria. First a systematic nomenclature based on stability constants is introduced. Next, practical aspects of potentiometric pH titrations and spectrophotometric titrations are discussed. The description of the computational aspects includes the NewtonRaphson algorithm tha...

A number of potentiometric biosensors based on coimmobilization of enzymes with different types of zeolite on pH-ion-sensitive field-effect transistor (ISFET) have been developed. Their working characteristics have been determined and compared. It was shown that clinoptilolite and zeolite Beta polymorph A (BEA) are more promising for creating biosensors than zeolite A. Changing the concentratio...

The reaction between phenothiazine and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) in the presence of p-toluenesulfonic acid in chloroform was investigated by potentiometry, voltammetry and spectrophotometry, and the reaction pathways were proposed. The conditions for the oxidimetric titration of phenothiazines with a standard chloroform solution of DDQ were optimized and the potentiometric...

The formation of complexes of Zn(II), Cd(II), Hg(II), and Pb(II) and N -carboxymethylD,L-threonine (H2CMT, H2L) in aqueous solutions has been studied by spectrophotometric and potentiometric methods. The complexation model for each system has been established by the HYPERQUAD program from the potentiometric data. Three different behaviors are found: ML2H, MLH, ML, MLOH, and ML2 complexes are fo...

The half-cell potential of the Activated carbon (AC), due to its high double layer capacitance (EDL), remains stable in high ionic electrolyte. The open circuit potential (OCV) of the AC, with EDL of 40 – 50 F, shows a stable potential (10 mV variation) over two weeks in the cement pore solution (sat. Ca(OH)2). The OCV is less sensitive to the pH change from pH 8 to 12 (range inside concrete). ...

A potentiometric enzyme biosensor is a convenient detector for quantification of urea concentrations in industrial processes, or for monitoring patients with diabetes, kidney damage or liver malfunction. In this work, poly(3-hexylthiophene-co-3-thiopheneacetic acid) (P(3HT-co-3TAA)) was chemically synthesized, characterized and spin-coated onto conductive indium tin oxide (ITO) glass electrodes...

A thiocyanate poly(vinyl chloride) (PVC) membrane electrode based on [1,2-bis(diphenylphosphino)ethane]dihalopalladium(II), [(dppe)PdX2, X = Cl (L), X = I (L)] as active sensor has been developed. The diiodopalladium complex, [(dppe)PdI2](L) displays an anti-Hofmeister selectivity sequence: SCN‒ > I‒ > ClO4‒ > Sal‒ > Br‒ > NO2‒ > HPO4‒ > AcO‒ > NO3‒ > H2PO4‒ > CO32‒. The electrode exhibits a Ne...

The effect of 1-decanol on the potentiometric response of three ion-selective electrodes to large cationic species is analyzed. The electrodes were constructed with plasticized PVC membranes. The results suggest that 1-decanol alters the ionic transport through the membrane/water interface to an extent that depends on the strength of the active ion pair. The water solubility of the cation, its ...