IT is well known that the cations of many nitrogenous bases which cannot be directly titrated with alkali in aqueous solution submit to titration in the presence ofa suitable concentration offormaldehyde. This is true of certain ofthe cationic groups in the proteins and their hydrolytic products. In the case of the natural amino-acids and their peptides, the various cationic groups which may oc...

The fluorimetric titration behaVIOur of naphthylammes IS abnormal In that the sum of the reduced quantum yields of conjugated aCid and base passes through a minimum. Based on fluorescence quantum yield and I1fetime measuremc'lts, we e....plaln thiS behaVIOur by two Independent mechamsms: A dlabatlc quenching of the excltcd base by protons and a decrease of the e....clted cation's protolytlc diS...

A new Schiff base ligand (L) obtained by the condensation reaction of N-acetylaceto-otoluidineand 2-aminopropanoic acid (an amino acid), is used to synthesize four mononuclearcomplexes of [MLCl] and [ML2] types (where M = Cu(II) and Zn(II); L = Schiff base) bykeeping the metal and ligand ratio as 1:1 and 1:2 respectively. This ligand and its complexeshave been characterized on the basis of diff...

Synergistic antifungal activity of 5-fluorocytosine (5-FC) and amphotericin B was studied using an abbreviated checkerboard titration scheme. 5-FC was titrated in twofold increments (100 to 0.05 mug/ml) in the absence and presence of graded increments of amphotericin B (1.0. 0.5, 0.1, 0.05, and 0.01 mug/ml) in buffered yeast nitrogen base. A limited number of experiments were performed using ex...

In this paper, the surface stoichiometry, acid-base properties as well as the adsorption of xanthate at ZnS surfaces were studied by means of potentiometric titration, adsorption and solution speciation modeling. The surface proton binding site was determined by using Gran plot to evaluate the potentiometric titration data. Testing results implied that for stoichiometric surfaces of zinc sulfid...

From the reaction mechanism, it's evident that the reagent used for the titration needs to contain the following: Alcohol methanol was used originally, but in different variations of the reagent can be replaced by ethyl carbitol, methoxypropanol, ethanol, etc. Sulfur dioxide Iodine Base pyridine was used initially, but has since been replaced by imidazole, which assures a higher rate of reactio...

*Correspondence: T. D. Silva. Departamento de Farmácia. Faculdade de Ciências Biológicas e da Saúde. Universidade Federal dos Vales do Jequitinhonha e Mucuri, Campus JK. Rodovia MGT 367, Km 583, n° 5000, 39100-000, Diamantina, MG, Brasil. E-mail: [email protected] Development and validation of alternative methods by non-aqueous acid-base titration and derivative ultraviolet spectrophoto...