Abstract

DRESSLER, Valderi L. et al. Determination of fluoride in coal using pyrohydrolysis for analyte separation. J. Braz. Chem. Soc. [online]. 2003, vol.14, n.2, pp. 334-338. ISSN 0103-5053.  http://dx.doi.org/10.1590/S0103-50532003000200024.

A method for the determination of fluoride in coal using pyrohydrolysis for sample decomposition is proposed. An apparatus was constructed, and the influence of vanadium pentoxide (V₂O₅) as a catalyst for the pyrohydrolysis reaction was investigated. It was verified that V₂O₅ does not influence the release of fluoride from coal. Certified and non-certified samples were analysed using an ion selective electrode (ISE) for analyte detection. Precise (RSD < 7%) and accurate (recovery in accordance with certified values) results were obtained. The limit of quantification (LOQ) of the method was 5.0 mgF/g of sample, using 20 mg of sample and a final dilution to 10 mL. The sample frequency was 5 samples h^-1.

Keywords : coal; fluoride; pyrohydrolysis; ion electrode; vanadium pentoxide; catalyst.