Comprehensive study of tartrazine/cationic surfactant interaction

Area of Science:

• Colloid and Surface Science
• Supramolecular Chemistry
• Food Chemistry

Background:

• Food dyes like tartrazine can interact with surfactants.
• Cationic surfactants, including conventional (TTAB) and gemini types (14,4,14 and 12,4,12), are widely used.
• Understanding these interactions is crucial for various applications.

Purpose of the Study:

• To investigate the interaction between tartrazine and cationic surfactants.
• To characterize the formation of ion pairs, premicelles, and micelles.
• To explore the structural changes induced by these interactions.

Main Methods:

• Conductometry
• Tensiometry
• UV-visible spectroscopy
• Job's method of continuous variations
• Transmission electron microscopy (TEM)
• Dynamic light scattering (DLS)
• Cyclic voltammetry

Main Results:

• Tartrazine behaves as an aromatic counterion, forming ion pairs with surfactants.
• Complex micellar structures, including dye-containing and surfactant-rich micelles, were observed.
• Insoluble J-aggregates and cylindrical micelles were identified in systems with gemini surfactants.
• Cyclic voltammetry successfully tracked species using tartrazine's reduction peak.

Conclusions:

• Tartrazine-surfactant interactions lead to the formation of diverse supramolecular structures.
• Gemini surfactants induce unique aggregate formations with tartrazine.
• The study provides a comprehensive understanding of tartrazine-surfactant systems and introduces a novel electrochemical tracking method.