Metabisulfite anion is widely used as an antioxidant agent and preservative of a number of industrialized products. The interaction of this agent with pararosaniline dye can reduce the absorption band of the pigment within the visible area. From the best experimental conditions such as Britton-Robinson buffer solution, pH 5.0, and dye in a solution of 1.0x10-4 mol L-1, it was possible to obtain a relation between concentration of metabisulfite and absorbance in a range from 1,3x10-6 mol L-1 to 3.0x10-5 mol L-1. The detection limit was calculated in 5.0x10-7 mol L-1. The methodology was applied on real samples.
Metabisulfite; Pararosaniline; Spectrophotometry
