Development of standardized method for the quantification of azo dyes by UV-Vis in binary mixtures

Area of Science:

• Analytical Chemistry
• Spectroscopy
• Dye Chemistry

Background:

• Azo dyes like Yellow 5, Red 2, and Blue 1 are widely used but challenging to quantify in mixtures due to spectral overlap.
• Traditional UV-Vis spectroscopy methods struggle with the shielding effect in dye mixtures, impacting accuracy.
• Existing quantification methods may lack the precision required for complex dye formulations.

Purpose of the Study:

• To develop and validate a novel CIE algorithm for accurate quantification of azo dye binary mixtures.
• To compare the accuracy of the CIE algorithm against traditional linear methods and UHPLC.
• To assess the applicability of the CIE algorithm for diverse dye mixtures within specific concentration and pH ranges.

Main Methods:

• UV-Vis spectroscopy was employed to study Yellow 5, Red 2, and Blue 1 in solutions and binary mixtures.
• A CIE algorithm based on the tristimulus chromaticity diagram, developed in Visual Basic for Applications (VBA), was utilized.
• The algorithm was tested as an alternative to overcome spectral interference in dye mixtures and compared with linear methods and UHPLC.

Main Results:

• The CIE algorithm achieved high accuracy rates of 97-99% in quantifying dye mixtures.
• Linear methods demonstrated lower accuracy, ranging from 78-98%.
• The algorithm's results were comparable to the UHPLC reference method, indicating high reliability.

Conclusions:

• The CIE algorithm provides an accessible and reliable method for quantifying binary azo dye mixtures.
• This approach effectively addresses the shielding effect, offering superior accuracy to linear UV-Vis methods.
• The study suggests potential application of this algorithm to other dyes within the established quantification limits (0.076-24.56 mg/L) and pH range (2-10).