Extraction of Drugs and other Chemical Residues from Tissues using SPE Trapping Techniques

Significance of the Topic

Isolation of trace-level drug residues from complex tissue matrices is vital for ensuring food safety, pharmaceutical quality control, and environmental monitoring. Conventional extraction techniques often suffer from lipid co-extraction and extensive solvent use leading to lengthy cleanup steps.

Objectives and Study Overview

This work aims to establish a streamlined method combining supercritical fluid extraction (SFE) with solid phase extraction (SPE) trapping to efficiently separate and recover pharmaceutical residues from biological tissues while minimizing lipid interference.

Methodology and Instrumentation

The approach integrates CO2-based supercritical extraction with offline and inline SPE trapping:

• Offline trapping uses an Applied Separations Spe-ed SFE system equipped with an inline sorbent trap and an external micrometering valve directing extract to an SPE column.
• Inline trapping packs the SPE sorbent within a Teflon sleeve inside the extraction vessel, followed by a conventional SPE column for cleanup.

Instrumentation and materials:

• Supercritical Extraction System: Applied Separations Spe-ed SFE-2 or Helix.
• Sorbents: Spe-ed Matrix and Spe-ed Wool.
• Extraction Fluid: Supercritical CO2 (SFE grade).

Main Results and Discussion

The method was validated across a range of analytes and tissue matrices with recovery rates demonstrating robust performance:

• Nitrobenzamides in chicken liver (1 ppm): 82–96 %
• Nitrosamines in frankfurters (20 ppb): 88–101 %
• Sulfonamides in chicken tissues (1 ppm): 77–89 %
• Anabolic steroids in chicken liver (500 ppb): 53–100 %
• Melengestrol acetate in bovine fat (25 ppb): 90–124 %
• Steroids in urine (12 ppb): 91–94 %
• Clenbuterol in bovine liver (0.5 ppb): 82–112 %
• Avermectins in bovine, ovine, porcine liver (2 ppb): 76–97 %
• Organochlorine pesticides in eggs (50 ppb): 82–108 %

These results confirm effective analyte recovery with minimal lipid co-extraction, streamlining sample cleanup.

Benefits and Practical Applications

This combined SFE/SPE method offers several advantages:

• Reduced organic solvent usage and waste.
• Faster sample preparation and cleanup.
• High recoveries across diverse analytes and matrices.
• Applicability to food safety testing, pharmaceutical analysis, and doping control.

Future Trends and Potential Applications

Advancements may include integration of automated inline SPE modules, coupling with high-resolution mass spectrometry for direct analysis, development of novel sorbents for improved selectivity, and expansion to environmental and clinical matrices, further aligning with green analytical chemistry principles.

Conclusion

The SFE/SPE trapping technique provides a robust, efficient, and environmentally friendly platform for trace-level drug residue extraction from tissue samples, overcoming challenges associated with lipid interference and solvent use.

Reference

No literature references were provided in the source document.