1. Titration of haem with pyridine in alkaline media of low ionic strength yields a true pyridine haemochromogen, compound III, at very low concentrations of pyridine. 2. Graphical analysis of this titration gives the first spectrophotometric evidence for a dimeric haem. 3. Compound III is unstable and tends to aggregate to a second compound, compound II, whose formation is enhanced under those...

HutB, the periplasmic hemin binding protein of Photobacterium damselae subsp. piscicida, was produced as a recombinant protein. UV-Vis spectrophotometrical analysis showed absorption spectral changes in hemin upon mixing it with the recombinant protein, indicating complex formation. Spectrophotometric titration of HutB with hemin showed saturation at a heme/HutB ratio of 1:1 and a binding affin...

The 50% spectrophotometric complement titration end-point (C'H50) was found to be more reproducible than the 100% end-point. The relationship of the 100% end-point (MHD) to the (C'H50) was 1:2, 5. The use of thrombin tubes induced clotting within 2 min and enabled the process of complement preparation to be completed well within 1 hour.

A multiwavelength spectrophotometric (WApH) titration method for determinatio constants (pΚa values) of ionisable compounds developed previously was applied derivatives of pharmaceutical interest. Specifically, UV absorption spectra of the drug the course of a pH-metric titration using an optical device based on a fibre optics dip pr diode array detector. Target factor analysis was applied to d...

The acid dissociation constants of the hydroxyl groups in 25, 26, 27, 28-tetrahydroxy-5, 11, 17, 23-tetrasulphonic-calix[4]arene (SC4) were determined at 25οC by a combination of potentiometric and spectrophotometric titration method. The first and second acid dissociation constants (pKa1, pKa2) were found to be 3.19 and 12.1, which demonstrated pKa shift due to intramolecular hydrogen bonding ...

Medium or high charge density cationic polyelectrolytes are frequently used for water treatment. In the papermaking wet-end they are used as retention agents or as flocculating aids. Negative polyelectrolytes that enter the papermaking system increase the demand for cationic polyelectrolytes. Polyelectrolyte concentration can be determined by the colloidal titration method, using either of two ...

An ultraviolet spectrophotometric and a nonaqueous volumetric method for determining terbinafine hydrochloride (TH) in pharmaceutical formulations are presented. The UV spectrophotometric procedure was developed for assay of TH in raw materials, tablets, and creams. The method was tested for linearity (0.8-2.8 micrograms/mL, r = 0.9997), recovery (102.00% for creams and 99.90% for tablets) and ...

The interaction of p-sulphonatocalix [6] arene towards L-arginine and L-lysine has been studied inacidic aqueous solution (p1-1 2) using UV-Vis spectrophotometric titration technique. The psulphonatocalix[6] arene was found to be able to form 1:1 complexe with amino acids in water.The values of the association constant were determined at different temperatures to evaluate thethermodynamic funct...

spectrophotometric and electrochemical studies were successfully used in quantitative analysis of amitriptyline hydrochloride (ath) and nortriptyline hydrochloride (nth). conductometric titration were carried out in equeous solution using iodide and dopamine and serotonine as titrant. two new methods using spectrophotometry are dascribed for the determination of (ath) and (nth) with potassium b...