Interaction of glyphosate (N-(phosphonomethyl)-glycine) with six polyamines (ethylendiamine, cadaverine, putrescine, triethylenetetramine, spermine, and tetraethylenepentamine) was studied potentiometrically. Several species of different stoichiometry are formed in the various systems, according to the general formation reaction i1 (j 2 3) (i 1 j 2 3) AH 1 H (glp) 5 A(glp)H i j i 1 j (where A 5...

The cytochrome bo quinol oxidase of Escherichia coli is one of two respiratory O2 reductases which the bacterium synthesizes. The enzyme complex contains copper and 2 mol of b-type heme. Electron paramagnetic resonance (epr) spectroscopy of membranes from a strain having amplified levels of this enzyme complex reveals signals from low- and high-spin b-type hemes, but the copper, now established...

A new method for determining chlorinity of water was developed in order to improve the old method by alleviating the environmental problems associated with the toxic chromate. The method utilizes a mediator, a weak acid that can form an insoluble salt with the titrant. The mediator triggers a sudden change in pH at an equivalence point in a titration. Thus, the equivalence point can be determin...

Kugelmass and Stuber and Lang have reported that the coagulation of blood or solutions of fibrinogen is accompanied by an increased alkalinity of the free fluid, which the former definitely ascribes to an absorption of hydrogen ions by the clot. Hirsch, however, reports an increased acidity, and suggests that it is the actual cause of coagulation; and Hekma in claiming that fibrinogen is the al...

1. The electromotive forces which arise, if two electrolyte solutions are separated from each other by a layer of any kind, are discussed. A general equation is derived comprising the known equations for diffusion, partition, and membrane (Donnan) potentials as special cases. 2. A method is proposed to analyse membranes potentiometrically with respect to their cation or anion selectivity, their...

The new ligand, [(1,4,8,11-tetraazacyclotetradecan-1-yl)methyl]phosphonic acid (H(2)te1P, H(2)L), was synthesized and its complexing properties towards selected metal ions were studied potentiometrically. The ligand forms a very stable complex with copper(ii)(logbeta(CuL)= 27.34), with a high selectivity over binding of other metal ions (i.e. logbeta(ZnL)= 21.03). The crystal structures of the ...

The system formed between bismuth(III) ion and D-gluconic acid was potentiometrically studied in aqueous solution. Measurements were carried out at 20.0 and 25.060.18C and the ionic strength was maintained at 0.100 M with NaNO . The potentiometric curves 3 showed the release of four protons in addition to the carboxylic one, leading to the formation of complexes with different degrees of deprot...

Two simple and accurate methods are described for the determination of piroxicam and tenoxicam in their pharmaceutical preparations. The spectrophotometric method involves the oxidation of these drugs with potassium iodate in acid medium with the liberation of iodine and subsequent extraction with cyclohexane followed by measuring the absorbance at lambda=522 nm. Beer's law is obeyed in the con...

Based on the nitrogenous base or tertiary amine moiety in zolmitriptan (ZMT), an anti-migraine drug, two highly accurate and selective titrimetric methods are proposed for the determination of ZMT in bulk drug and pharmaceuticals. In these methods, the drug dissolved in glacial acetic acid, was titrated with acetous perchloric acid and end point determined either visually by using crystal viole...

The interaction of [Ru(III)(edta)(H(2)O)](-) with a series of selected thiols having extra functional groups was investigated potentiometrically and kinetically. The pK(a) values of the uncoordinated carboxylic acid group and coordinated water molecule are 3.12 and 7.41, respectively, in aqueous solution at 25 degrees C and 0.1 M ionic strength. The formation constants of the complexes were det...