Separation of pigment formulations by high-performance thin-layer chromatography with automated multiple development

Area of Science:

• Analytical Chemistry
• Food Science
• Materials Science

Background:

• Food packaging requires quality control of printing materials for safety and appearance.
• Existing analytical methods are insufficient for analyzing complex, poorly soluble pigment formulations.
• Ensuring consistent ink quality and preventing migration of harmful components is crucial for consumer safety.

Purpose of the Study:

• To develop a simple, generic, and robust analytical method for quality assurance of pigment formulations in food packaging inks.
• To enable routine quality control of incoming pigment batches and internal production processes.
• To assess the bioactivity and toxicological potential of pigment components for enhanced consumer safety.

Main Methods:

• Development of a high-performance thin-layer chromatography (HPTLC) method using silica gel 60 plates and automated multiple development.
• Utilized multi-detection, hyphenation with high-resolution mass spectrometry (HRMS), and infrared spectroscopy (IR) for band characterization.
• Coupled HPTLC with the *A. fischeri* bioassay to evaluate toxicological potential.

Main Results:

• The HPTLC method achieved sharp resolution of pigment constituents, including additives and coating materials.
• Analysis revealed substantial variations in the composition of commercially available pigment batches.
• Hyphenation allowed characterization of unknown pigment constituents potentially causing quality issues; bioassay provided initial toxicity data.

Conclusions:

• The developed HPTLC method is precise, selective, and suitable for routine quality control of pigment formulations.
• This method ensures consistent ink quality, faultless print images, and safe food packaging products.
• Integration with bioassays aids in selecting safer pigment compositions, minimizing migration risks and enhancing consumer safety.