Quantitative Headspace Measurement of Volatiles in Dairy Products using Vacuum Assisted Sorbent Extraction (VASE) and GCMS Analysis

Importance of the Topic

Analysis of volatile and semi-volatile compounds in dairy products is crucial for quality control, flavor profiling and detection of spoilage or contamination. Conventional headspace approaches often struggle to recover low-volatility analytes in fatty matrices, making sensitive, reproducible extraction methods highly valuable for research and industry.

Goals and Overview of the Study

This application note presents the use of Vacuum Assisted Sorbent Extraction (VASE) combined with gas chromatography mass spectrometry (GCMS) to quantify headspace volatiles in milk, eggnog, cheddar and brie cheese. The study aims to demonstrate enhanced recovery of heavier polar compounds, evaluate reproducibility, and illustrate broad dynamic range from light acids to cholesterol.

Methodology and Instrumentation

The VASE workflow utilizes sorbent pens packed with 70 mg of Tenax adsorbent placed directly into sample vials. A vacuum (<0.01 atm) is applied through a tight interface to promote static diffusion until equilibrium is reached (2–24 h, 4–70 °C). Key instruments include:

• 3801 Sorbent Pen Thermal Conditioner for pen conditioning and bake-out
• 5600 Sorbent Pen Extraction System for controlled temperature and agitation
• 5800 Sorbent Pen Desorption Unit interfaced to an Agilent 7890/5977 GCMS

Main Results and Discussion

Milk and eggnog extracts recovered formic and acetic acids, furfurals, fatty acids up to cholesterol in a single analysis. Cheese samples yielded ketones, lactones, sulfides, esters and terpenes. Duplicate extractions showed high reproducibility and no carryover after bake-out. Non-polar GC columns detected many acids, though intermediate polarity columns could improve separation of polar volatiles.

Benefits and Practical Applications

• Improved recovery of low-volatility compounds 10–50× over classical SPME
• Zero carryover and consistent performance without extensive conditioning
• Static diffusion under vacuum eliminates channeling effects in packed traps
• Compatibility with routine flavor, taint and QA/QC analyses in dairy and related matrices

Future Trends and Possibilities

Further research may explore microbial stability under vacuum, extended room-temperature storage, application of VASE to other complex food and environmental matrices, and integration with isotope-dilution protocols for absolute quantitation.

Conclusion

Vacuum Assisted Sorbent Extraction coupled with GCMS offers a sensitive, reproducible and broad-range technique for profiling volatiles in dairy products. Its high recovery of heavy polar analytes and minimal carryover make it a promising tool for industrial and academic laboratories seeking detailed aroma and safety assessments.

Reference

• Victoria L. Noad and Daniel B. Cardin Quantitative Headspace Measurement of Volatiles in Dairy Products using Vacuum Assisted Sorbent Extraction and GCMS Analysis Application Note V-3741-01 Entech Instruments 2017