Portal de Periódicos da CAPES

Voltammetric Determination of Free and Total Sulfur Dioxide in Beer

2003; Wiley; Volume: 15; Issue: 5-6 Linguagem: Inglês

10.1002/elan.200390073

1521-4109

Paulo Almeida, José A. Rodrigues, Luís F. Guido, João Rodrigo Santos, Aquiles A. Barros, Arnold G. Fogg,

Electrochemical sensors and biosensors

Abstract A voltammetric method for the determination of free and total sulfur dioxide in beer is described. First, volatile aldehydes (mainly acetaldehyde) are purged with nitrogen from a beer sample diluted in alkaline medium, collected in an appropriate electrolyte trapping solution and determined, after derivatization with hydrazine, by voltammetry using a hanging mercury drop electrode. Then, the remaining beer solution is strongly acidified and (total) sulfur dioxide is purged with nitrogen, collected in an appropriate electrolyte trapping solution and determined by voltammetry. The free sulfur dioxide concentration is calculated by difference between (total) sulfur dioxide and acetaldehyde concentrations. The proposed method has a relative standard deviation of about 2.1% and 4.4%, respectively for (total) sulfur dioxide and free sulfur dioxide concentrations normally found in beer, and results are in good agreement with those obtained by the p ‐rosaniline reference method.