Spectrophotometric Determination of Iodate in Table Salt

• Autor(a) principal: Silva,Rosa Lina G.N P.
• Data de Publicação: 1998
• Outros Autores: Oliveira,A. Fernando de, Neves,Eduardo Almeida
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50531998000200009
• topic: iodized salt; spectrophotometry; salt; iodate

Potassium iodate in table salt can be spectrophotometrically determined at two well defined UV absorption maxima (288 and 352 nm), after being converted to I3- by reaction with iodide in the presence of phosphoric acid Calibration curves with slopes of 7.320 x 10(4) and 1.103 x 10(5) L mol-1 cm-1 were obtained at 352 and 288 nm, respectively, at 22 °C. Typical results of 37.39 (±0.15) and 63.67 (±0.16) mg KIO3 per kg of salt were obtained with samples of 0.15-0.21 g, comparable with results from a standard but less precise iodometric titration of large samples (20-50 g). The method has been found adequate for checking homogeneity of iodine distribution in table salt, as small weighed samples are normally required.