Deep eutectic solvent induced silver-gel as a flexible SERS substrate for sensitive detection of antibiotics under low temperature conditions.

Antibiotic residues pose a significant threat to global health. Traditional detection methods for antibiotics are cumbersome, time-consuming and often incapable of achieving non-destructive detection at low temperatures. This research introduces a groundbreaking innovation in antibiotic detection: a flexible Surface-Enhanced Raman Scattering substrate based on a silver composite deep eutectic solvent (DES) gel, specifically engineered for low-temperature antibiotic detection. To address the challenge of low SERS response for antibiotics, we utilize R6G (Rhodamine 6 G) to effectively label them. This unique SERS substrate exhibits exceptional mechanical robustness, stability, and frost-resistance. Remarkably, it enables the direct and sensitive detection of six types of labeled antibiotics across four categories in frozen chicken wings at -25 °C, with a limit of detection (LOD) below 1.3 × 10-9 mol/L. Additionally, the substrate demonstrates outstanding homogeneity (relative standard deviation (RSD< 6.4 %), reproducibility (RSD < 6.2 %), and long-term stability over 30 days, ensuring highly sensitive and quantitative antibiotic detection. Theoretical insights reveal that the labeled antibiotics exhibit higher binding energy with silver, further enhancing detection sensitivity. This novel, flexible substrate holds immense potential for quantifying antibiotics in frozen foods and heralds a new era of expanded detection capabilities for a broader spectrum of antibiotics at low temperatures.