Extraction of Sulfonamides from Chicken Liver using Supercritical Fluoroform (CHF3)

Importance of the Topic

Supercritical fluid extraction (SFE) provides an efficient and environmentally friendly approach to isolate trace analytes from complex biological samples. It reduces solvent usage and lowers coextracted interferences, making it valuable for food safety and pharmaceutical analysis.

Objectives and Overview of the Study

This application note presents a method for extracting sulfonamide antibiotics from fortified chicken liver using supercritical fluoroform as the primary solvent. The study aims to achieve high recovery rates while minimizing coextracted lipids and reducing solvent consumption compared to conventional techniques.

Methodology and Instrumentation

• Sample Preparation:
  • Homogenize 1 g of chicken liver and spike with a sulfonamide mixture (sulfamethazine, sulfadimethoxine, sulfaquinoxaline).
  • Mix with Spe-ed Matrix and pack into a 10 mL extraction vessel between SPE wool plugs.
• Extraction Conditions:
  • Solvent: Supercritical fluoroform modified with methanol (200 µL/min).
  • Pressure: 6500 psi; Temperature: 40 °C; Dynamic extraction time: 30 minutes.
  • CHF3 flow rate: 2 L/min; Valve temperature: 120 °C.
  • Collection: C18 SPE cartridge; Elution with 5 mL of 0.5 M phosphate buffer/methanol (50/50).
• Instrumental Setup:
  • Supercritical extraction system: Spe-ed™ SFE-2 or Helix.
  • SFE modifier pump and sample collection assembly with SPE cartridges and Spe-ed wool.
  • HPLC Analysis: Waters 6000 pump; C18 column (250 × 4.6 mm, 5 µm); mobile phase 60/40 phosphate buffer (pH 7.1)/methanol; flow rate 1 mL/min; UV detection at 265 nm.

Main Results and Discussion

• Extraction Efficiency:
  • Sulfamethazine: 99.8 % recovery (RSD 4 %).
  • Sulfadimethoxine: 85.8 % recovery (RSD 12 %).
  • Sulfaquinoxaline: 31.2 % recovery (RSD 14 %).
• The high recovery for sulfamethazine and sulfadimethoxine demonstrates the selectivity of methanol-modified CHF3 for medium-polar analytes, while lower sulfaquinoxaline recovery suggests optimization potential.
• Fluoroform reduced lipid coextraction, simplifying downstream cleanup and improving extract clarity.

Benefits and Practical Applications

• Significantly cleaner extracts with reduced fat content.
• Efficient off-line SPE collection without additional cleanup steps.
• Lower solvent usage and faster processing times compared to conventional extraction methods.
• Applicable to routine QA/QC of veterinary drug residues in food matrices.

Future Trends and Opportunities

Advancements in SFE technology and solvent modifiers may further enhance extraction selectivity for a wider range of analytes. Integration with automated SPE and on-line coupling to LC–MS platforms could streamline workflows. Research into alternative green supercritical fluids and nanomaterials as stationary phases holds promise for improved sensitivity and throughput in pharmaceutical and food safety testing.

Conclusion

The use of supercritical fluoroform modified with methanol provides a robust and environmentally friendly approach for extracting sulfonamides from chicken liver. High recoveries, reduced lipid interference, and simplified cleanup demonstrate its value as an alternative to traditional solvent-intensive protocols.

References

1. Ashraf-Khorassani, M.; Taylor, L. Comparison of Supercritical CHF3 and CO2 and Methanol-modified CHF3 and CO2 for Extraction of Sulfonamides from Chicken Liver. Journal of AOAC International 1996, 22 (5), 1043–1049.