An on-line system for enrichment and determination of lead(II) is presented. It is based on the adsorption of lead(II) ions on a minicolumn packed with active carbon loaded with Pyrogallol Red. After preconcentration step, the metal ions are eluted automatically by 5.0 ml of 0.50 M nitric acid solution and the lead ion contents were determined by atomic absorption spectrometry. The influence of...

abstract kinetic properties of root of peroxidase of gundelia tournefortii investigated at different ph, temperature and different inhibitors. maximum activity of peroxidase achieved at ph 5.5-6 in according to type of substrate. activity of peroxidase increased at constant concentration of h2o2 and different concentration of guaiacol, catechol and pyrogallol. the maximum activity in presence o...

UNLABELLED Clinical and experimental study. Introduction. Of debatable etiology, Recurrent Aphthous Ulcerations (R.A.U), is most of the time considered an immunological deficiency. AIM The aim of this paper is to review the literature and clinical investigations regarding IgA-s, total proteins salivary concentration and basal salivary flow of patients with R.A.U. during activity and quiescenc...

We introduce pyrogallol end-functionalized telechelic PEGs that are crosslinked with di- or trivalent ions to result in self-healing, adhesive hydrogels whose mechanical properties can be varied over an unprecedented range.

This work presents a sensitive method for the determination of trace antimony based on the antimony-pyrogallol red (PGR) adsorption at a carbon paste electrode (CPE). The optimal conditions were to use an electrode containing 25% paraffin oil and 75% high purity graphite powder as working electrode, a 0.10 mol/L HCl solution containing 3.0×10 mol/L PGR as accumulation medium and a 0.20 mol/L HC...

The anti-peroxyl radical quality of two aqueous rooibos infusions and solutions of their most abundant glycosylated polyphenols was evaluated using pyrogallol red and fluorescein-based oxygen radical absorbance ratios. It was observed that the artificial infusions, prepared using only the most abundant polyphenols present in rooibos and at concentrations similar to those found in the natural in...

Polyphenol oxidase (PPO) from tomatoes was extracted and partially purified through  (NH4)2SO4 precipitation, dialysis and ion exchange chromatography. The activity of polyphenol oxidase was investigated in solanum lycopersicum. Spectrophotometric method was used to assay the enzyme activity and the kinetic constants - maximum enzyme velocity (Vmax) and Michealis - Menten constant (Km). Of the ...

Ii(loleacetic acid is inactivated by mushroom tyrosinase or a tyrosinase present in dialyzed extracts of Osmunda leaves, but only when catechol or pyrogallol are also added. Tyrosine and DOPA do not promote IAA inactivation, although these phenols are oxidized by the enzvme. It appears probable that a reaction occurs between IAA and one of the intermediate compounds formed during the oxidation ...