Accelerated Solvent Extraction (ASE) Sample Preparation Techniques for Food and Animal Feed Samples

Significance of the Topic

Proper sample preparation is critical in accelerated solvent extraction (ASE) to achieve accurate, reproducible analyte recovery from complex food and animal feed matrices. Optimized pretreatment and clean-up protect analytical instruments, reduce interferences, and support reliable QA/QC workflows.

Objectives and Study Overview

This technical note evaluates a range of pretreatment, in-cell clean-up, solvent selection, and method development strategies for ASE of food and feed samples. The goal is to maximize extraction efficiency, minimize solvent consumption, and produce clean extracts ready for analysis.

Methodology and Instrumentation

Pretreatment approaches:

• Moisture removal: air drying, lyophilization, oven or microwave drying
• Sample dispersal: mixing with diatomaceous earth (ASE Prep DE) or clean sand to prevent compaction and promote solvent penetration

In-cell clean-up and filtration:

• Cellulose or glass-fiber filters at the cell outlet to retain particulates
• Adsorbents: acidic alumina (Al₂O₃) for lipid removal, C18 bonded silica for organic contaminants retention

Solvent selection guidelines:

• Match solvent polarity to target analyte and analytical technique (e.g., hexane/isopropanol for lipids; dichloromethane/acetone for PAHs; acetonitrile or acidified methanol for polar compounds)
• Avoid strong mineral acids and caustics that damage stainless steel and pump components

ASE parameter framework:

• Standard ASE Conditions (SAC): 100 °C, 1500 psi, 1 cycle × 5 min static, 60 % flush, purge 60–100 s
• Adjust temperature, solvent, static time, and flush volume to optimize recovery and extract cleanliness

Main Results and Discussion

Increased sample surface area by grinding enhanced fat recovery in cheese compared to Mojonnier extraction. In-cell alumina effectively retained co-extracted lipids during pesticide and organochlorine analysis. Iterative method development on rodent feed showed that raising temperature improved analyte yield but risked co-extractables, while refining static time and flush volume yielded clear, high-recovery extracts.

Benefits and Practical Applications of the Method

ASE reduces extraction time and solvent volumes, delivers high reproducibility, and integrates in-cell clean-up to streamline workflows. Applications include quantitative determination of pesticides, lipids, mycotoxins, veterinary drugs, and environmental contaminants in diverse food and feed matrices.

Future Trends and Potential Applications

Emerging directions include coupling ASE with LC-MS and GC-MS for rapid screening, developing novel sorbent materials for selective in-cell clean-up, implementing greener solvent systems, and miniaturized ASE platforms for high-throughput and sustainable analysis.

Conclusion

By combining tailored pretreatment, solvent optimization, in-cell clean-up, and parameter refinement, ASE offers a robust, efficient approach for preparing food and feed samples. This methodology enhances data quality, reduces manual steps, and supports stringent analytical requirements.

Instrumentation Used

Thermo Scientific ASE® accelerated solvent extractor, models ASE 200 and ASE 300.

References

1. Application Note 326: Extraction of Drugs from Animal Feeds Using ASE.
2. Application Note 349: Organochlorine Pesticides in Animal Feed.
3. Application Note 353: Sulfonamide Residues in Animal Tissue and Infant Food.
4. Application Note 322: Selective PCB Extraction from Fish Tissue.
5. Application Note 321: Unbound Fat in Food Matrices.
6. Application Note 325: Oil Extraction from Oilseeds.
7. Application Note 329: Total Fat in Powdered Infant Formula.
8. Application Note 332: Pesticide Residues in Food.
9. Application Note 334: Fat in Meat.
10. Application Note 335: Active Ingredients from Natural Products.
11. Application Note 340: Fat in Dried Milk Products.
12. Application Note 342: PCBs in Large-Volume Fish Tissue.
13. Application Note 343: Pesticides in Large-Volume Food Samples.
14. Application Note 344: Fat Extraction from Chocolate.
15. Application Note 345: Fat Extraction from Dairy Products.
16. Application Note 350: Zearalenone in Wheat and Corn.
17. Application Note 409: Acrylamide in Food via ASE/IC.
18. Gentili A. et al., J. Agric. Food Chem. 2004, 52, 4614–4624.