Publications by authors named "Miguel A Botelho"

This paper integrates perspectives from analytical chemistry, environmental engineering, and industrial hygiene to better understand how workers may be exposed to perfluorinated carboxylic acids when handling them in the workplace in order to identify appropriate exposure controls. Due to the dramatic difference in physical properties of the protonated acid form and the anionic form, this family of chemicals provides unique industrial hygiene challenges. Workplace monitoring, experimental data, and modeling results were used to ascertain the most probable workplace exposure sources and transport mechanisms for perfluorooctanoic acid (PFOA) and its ammonium salt (APFO).

View Article and Find Full Text PDF

Perfluorooctanoate (PFO) is the anion of perfluorooctanoic acid. As the ammonium salt, PFO has been used for 50 years as a processing aid in the commercial production of perfluorinated and highly fluorinated polymers. To assess the effectiveness of industrial hygiene controls in processes involving PFO products and intermediates, a wipe test was developed and validated to determine quantitatively the PFO concentration on six surfaces: stainless steel, polycarbonate, Formica, butyl acid suit material, laminated disposable suit material, and a painted surface.

View Article and Find Full Text PDF

To determine the optimum conditions for the complete extraction of perfluorooctanoate (PFO) from polytetrafluoroethylene fluoropolymers, sample preparation and pressurized solvent extraction (PSE) conditions were investigated. Solvent extraction temperature, solvent residence time, relaxation time between extractions, and the effects of heating before PSE showed that methanol at 150 degrees C extraction temperature and a 12 min solvent residence time were the most efficient conditions. Preheating the polymer before extraction at 150 degrees C for 24 h significantly enhanced the quantity of PFO removed.

View Article and Find Full Text PDF