Abstract:

Using the ability of basic orange Ⅱ to develop color, a fast method was presented for the determination of this dye. The optimal conditions for color development were investigated. A reagent system composed of potassium ferricyanide and Iron (Ⅲ) was found to the best color developer through comparative analysis of color developing effects of different color developers and observation of absorbance change, and the optimal ratio of potassium ferricyanide solution (3 g/L) to ferric chloride solution (4.5 g/L) was 1:1. The optimal reaction conditions were determined based on absorbance at 755 nm wavelength as follows: color developer amount, 0.7 mL; and reaction temperature, 50 ℃ for a reaction duration of 20 min.

Key words: basic orange Ⅱ, colorimetry, ast determination