Analysis of Oil and Fat containing foods by fully automated sample preparation using a PAL3 coupled with a 7890 GC and a 5977 MSD system according to AOAC 996.01

Importance of the Topic

The precise analysis of oils and fats is critical for nutritional labeling, regulatory compliance and quality assurance in food, agriculture and related industries. Fatty acid profiles influence product stability, health claims and consumer choices. Automated workflows reduce manual handling of hazardous reagents, improve laboratory safety and support high‐throughput demands.

Objectives and Study Overview

This study presents a fully automated sample preparation and GC–MS analysis of fatty acid methyl esters (FAMEs) in oils and fat‐containing foods based on AOAC Method 996.01. The goal is to demonstrate increased throughput, reduced solvent consumption and enhanced reproducibility by integrating a PAL3 robotic tool change (RTC) platform with an Agilent 7890B GC and 5977A MSD.

Methodology

The automated protocol follows these key steps:

• Aliquot extracted fat into sample vial and add internal standard (ISTD).
• Perform alkaline saponification with 0.5 M NaOH in methanol at reflux for 5 minutes.
• Esterify in situ by adding 12 % boron trifluoride in methanol and heating for 10 minutes.
• Extract FAMEs with heptane and promote phase separation with saturated NaCl solution.
• Transfer the organic layer to a GC vial for direct injection.

Used Instrumentation

• PAL3 RTC85 robotic sampler with MHE Module, Agitator and Fast Wash Station
• Agilent 7890B Gas Chromatograph with split Single-Taper SSL injector
• Agilent 5977A Mass Selective Detector operating in electron ionization mode
• MassHunter GC/MS software version B.07.03.2129

Main Results and Discussion

The automated workflow processed six samples in 1 hour 50 minutes, compared to 44 minutes per sample manually. Solvent and reagent usage dropped by a factor of ten, lowering costs and exposure risks. Reproducibility was evaluated in palm oil, fish oil and milk chocolate:

• Palm oil showed RSDs of 4–10 % across major FAMEs (C14–C18).
• Fish oil omega-3 EPA and DHA exhibited RSDs below 5 %, consistent with EU nutritional standards.
• Cocoa butter in milk chocolate matched literature profiles, with RSDs around 5–7 %.

These results confirm that automation yields comparable or better precision than manual methods.

Benefits and Practical Applications

• Enhanced laboratory safety by minimizing exposure to caustic and flammable reagents.
• Higher throughput enabling same‐day reporting for multiple samples.
• Reduced operational costs via lower solvent and consumable usage.
• Improved data consistency suitable for QC, regulatory audits and contract laboratories.

Future Trends and Potential Applications

Automation in lipid analysis is poised to expand with integrated online derivatization, coupling to LC–MS for polar lipid profiling and real‐time process monitoring. Advances in robotics and analytics will enable dynamic method adaptation for emerging food matrices and nutraceuticals.

Conclusion

The PAL3 automated sample preparation combined with Agilent GC–MS delivers a robust, high‐throughput solution for FAME analysis. It meets AOAC 996.01 requirements while significantly improving safety, reducing costs and maintaining excellent reproducibility across diverse food matrices.

References

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