The effect of spin finishes on hydrolysis rates of medical grade polyester.

Purpose: The rate of alkaline hydrolysis of medical grade poly(ethylene terephthalate) of grey, scoured, and solvent extracted samples have been studied to understand their degradation behavior during surface modification which is used to produce antithrombus grafts.

Methods: The changes in properties were examined using weight loss, mechanical properties loss and infrared spectrum.

Results: It was found that the rate of hydrolysis of grey sample was always slower than the scoured, and solvent extracted samples.

Electropolymerization of 3',4'-disubstituted 2,2':5',2″-terthiophene derivatives. A theoretical and photovoltaic characterization.

In the present work a series of β-substituted thiophenes have been synthesized and their electrochemical behavior studied. The products obtained by electro-oxidation are highly dependent on the substituent, affording sometimes conducting polymers, insulating layers or soluble species. This behavior has been ascribed to specific electronic and/or steric factors.

Determination of mercury in hair by square-wave anodic stripping voltammetry at a rotating gold disk electrode after microwave digestion.

A simple and reliable method for the determination of mercury in hair on a rotating gold disk electrode using subtractive anodic stripping voltammetry without removal of oxygen is reported. Voltammetric and microwave parameters were optimized to obtain the best analytical results. Parameters such as supporting electrolyte concentration, influence of chloride in the Hg peak, deposition potential, scan rate, accumulation time, rotation rate, square-wave amplitude, and electrode conditioning were studied.

Selenium and mercury concentrations in some fish species of the Madeira River, Amazon Basin, Brazil.

Samples of 7 species of piscivorous, omnivorous, and herbivorous fish caught at 12 different sites on the Madeira River, Amazon Basin, were analyzed for selenium and mercury. Selenium was determined by anodic stripping voltammetry and mercury by cold vapor atomic absorption spectrophotometry. The means for selenium concentrations ranged from 0.

Multivessel system for cold-vapor mercury generation. Determination of mercury in hair and fish.

A multivessel system for the determination of mercury (Hg) by cold-vapor atomic absorption spectrometry (CV-AAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES) was developed. The performance of the proposed device was tested by determining total Hg in quality-control samples of hair and fishes following acid digestion. Application of the apparatus to the determination of Hg by CV-AAS following alkaline digestion was studied as well.