Determination of Fe(III) using digital images: study of corrosion in steel plates using a polyester laser printed device

Autor(es)

Passaretti Filho, Juliano ; Gomes Valente Junior, Marco Antonio ; de Lima Gomes, Paulo Clairmont F. ; Fugivara, Cecilio Sadao ; Cardoso, Arnaldo Alves

• Tipo de documento: Artigo Científico
• Fonte: ANALYTICAL METHODS; v. 9, n. 4, p. 655-663, 2017.
• Citações Web of Science: 4

Resumo

The marketing of metals and metal alloys requires strategies for controlling the integrity of these materials. Corrosion of iron alloys results in the formation of oxides on the metal surface and can be quantified in units of mass loss of the metal. In this article, a method was developed for determining the mass of iron oxide formed on the surface of metal using a polyester laser printed spot device. The technique involves the oxidation of Fe(II) to Fe(III) and a subsequent reaction of Fe3+ with SCN- to form a colored species. This reaction, which is widely used in chemical methods, employs reagents that are readily available and inexpensive. A template with 90 spots of diameter 3.4 mm was printed on a transparency sheet using a commercial laser printer. Each spot was impregnated with 4 mu L of 0.190 mol L-1 ammonium thiocyanate solution. The reaction of Fe3+ with SCN- resulted in a product that absorbed in the visible region. Detection of the colored spots formed was performed automatically by acquisition of images with a scanner and a cell phone. The method developed was applied to the determination of corrosion rates in samples subjected to controlled corrosion processes. For comparison purposes, the corrosion was also determined by the gravimetric standard method. No significant differences between the results of both methods were observed, showing good performance with respect to the ASTM conventional reference method. The method developed offers advantages for routine analyses, with several spots that can be analyzed simultaneously and only a few units of mu L of sample were required. Other advantages inherent in the method are drastic reduction in the use of reagents and the analytical cost, as well as waste generation. (AU)

• Processo FAPESP: 15/23265-5 - Desenvolvimento de equipamento miniaturizado baseado mudança de propriedade óptica e gerenciamento por hardware livre para determinação de gases minoritários presente na atmosfera
• Beneficiário: Arnaldo Alves Cardoso
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/03369-3 - Desenvolvimento de sistemas microfluídicos a base de papel aplicados na análise de fármacos em águas residuárias
• Beneficiário: Paulo Clairmont Feitosa de Lima Gomes
• Modalidade de apoio: Auxílio à Pesquisa - Regular