Lignin-based hydrophobic DESs extracts Sudan dyes from aqueous solution

Area of Science:

• Green Chemistry
• Analytical Chemistry
• Materials Science

Background:

• Sudan red dyes are synthetic pigments used as food additives, posing significant health risks including kidney damage and carcinogenicity.
• Accurate detection of Sudan red in food and environmental samples is crucial for public health and regulatory compliance.

Purpose of the Study:

• To develop a novel, efficient, and environmentally friendly method for synthesizing lignin-based hydrophobic deep eutectic solvents (LHDES).
• To establish a sensitive and practical analytical method utilizing LHDES for the determination of Sudan red dyes in complex matrices.
• To evaluate the efficacy of the developed method in real-world applications, including food and water samples.

Main Methods:

• One-step synthesis of LHDES using alkali lignin as a hydrogen bond donor and methyltrioctylammonium chloride as a hydrogen bond acceptor.
• Characterization of LHDES properties using various analytical techniques to understand the formation mechanism.
• Development of a vortex-assisted dispersion-liquid microextraction (VA-DLM) method employing LHDES for Sudan red dye extraction.
• Application of the VA-DLM-LHDES method for the quantitative determination of Sudan Red I in seawater, river water, and duck blood samples.

Main Results:

• Successfully synthesized LHDES with tunable properties based on varying mass ratios.
• The formation mechanism of LHDES was elucidated through comprehensive characterization.
• The VA-DLM-LHDES method demonstrated high extraction efficiency, reaching up to 98.62% for Sudan Red I.
• The method proved effective for the determination of Sudan red in diverse real-world samples, including food matrices.

Conclusions:

• Lignin-based hydrophobic deep eutectic solvents offer a sustainable and effective alternative for extracting Sudan red dyes.
• The developed vortex-assisted dispersion-liquid microextraction method using LHDES is simple, sensitive, and practical for the determination of Sudan red in food and environmental samples.
• This research contributes to enhanced food safety by providing a reliable analytical tool for detecting harmful Sudan red contaminants.