A novel hydrophobic solidified deep eutectic solvents for rapid and accurate determination of Brilliant Blue in food and beverage

In this study, a novel hydrophobic solidified deep eutectic solvent (SFDES) was prepared and applied for the extraction and determination of Brilliant Blue (BB) in food and beverage matrices. The SFDES, prepared from benzyltriethylammonium chloride and fatty acids, is considered a greener alternative to conventional organic solvents, and excellent solidification properties, enabling efficient phase separation and analyte enrichment. Its structural and functional properties were confirmed by attenuated total reflectance Fourier-transform infrared spectroscopy, demonstrating successful formation of the eutectic system. Coupling the prepared SFDES with an ultrasonic-assisted dispersive liquid–liquid microextraction procedure allowed highly efficient extraction under optimized conditions, achieving a linear range of 0.1–30.0 mg L -1 , a low limit of detection of 1.49 µg L -1 , and a high enrichment factor of 65.9. The method was validated on real food samples, including jelly, candy, and soft drinks, yielding recoveries of 98.3–101.5% and intraday RSDs below 1.8%. The interday RSD values were 3.2%. Greenness evaluation using the GAPI and AGREE tools confirmed the approach’s environmental sustainability. These findings demonstrate that the newly made SFDES is a promising green extraction medium for trace-level determination of BB in complex food matrices. • Provided recoveries of 98.3–101.5% with excellent precision • Achieved ultra-low detection limit and high enrichment • Rapid, centrifugation-free extraction completed within 20 minutes • Greenness confirmed by GAPI and AGREE evaluations • A novel hydrophobic SFDES was prepared from BTEAC and fatty acids