Determination of Acid Dissociation Constants of Degradable Catecholamines by CZE

Determination of the acid dissociation constants of the p-sulphonato-calix[4]arene

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 ...

Multiwavelength spectrophotometric determination of acid dissociation constants of ionizable drugs.

A multiwavelength spectrophotometric approach has been developed to determine acid dissociation constants (pKa values) of sparingly soluble drug compounds. UV absorption spectra of the drug solution are acquired using a versatile device based on a fiber optics dip probe, a light source and a photodiode array (PDA) detector while the PH and the ionic strength of the chemical system is manipulate...

Determination of acid dissociation constant of degradable tetrabromophenolphthalein ethyl ester by capillary zone electrophoresis.

An acid dissociation constant of tetrabromophenolphthalein ethyl ester (TBPE) was determined through the measurement of electrophoretic mobility by capillary zone electrophoresis (CZE). Although TBPE is degradable in acidic pH region and it gradually degraded at pH conditions around and below its pKa values in the time scale of the CZE measurement, equilibrium species of interest were detected ...

First Principles Determination of Dissociation Rate Constants

Determination of Acidity Constants of p-Rosolic acid and Bromoxylenol Blue by Solution Scanometric Method

Recently solution scanometry, as a new, simple, fast, portable, and economic method was introduced for determination of acidity constants of indicator and dyes. In this study, a method was applied for the determination of the acidity constant of p-Rosolic acid (RA) and Bromoxylenol blue (BXB) indicators. The method is based on scanning of Plexiglas® sheet containing colored solutions with a fla...