Analysis of Volatile Organic Compounds in Different Beverages

Importance of the Topic

Volatile organic compounds (VOCs) are low-molecular-weight chemicals that can pose acute and chronic health risks. While drinking water regulations strictly limit VOC levels, commercially available beverages remain less scrutinized. Understanding VOC content in drinks ensures consumer safety, supports quality control, and helps laboratories adopt efficient analytical workflows.

Objectives and Study Overview

This work surveyed three leading soda brands, each in regular, diet, and zero-calorie formulations, packaged in cans and plastic bottles. The primary goal was to quantify 94 USEPA Method 8260C–listed VOCs using an automated in-vial purge approach coupled with gas chromatography–mass spectrometry (GC/MS). The study aimed to demonstrate method feasibility in complex, sugar- and acid-rich matrices and to compare VOC concentrations against drinking water guidelines.

Methodology and Sample Preparation

Samples (5 mL or 5 g) were transferred into 40 mL vials containing a magnetic stir bar and sealed. The Atomx system added 10 mL reagent water and introduced inert purge gas via a three-stage needle directly into the vial. VOCs and flavor compounds were stripped onto a proprietary adsorbent trap, then thermally desorbed into the GC/MS for separation and detection. Calibration employed a 50 ppm multi-component standard covering 94 analytes, diluted to working ranges of 1–200 ppb, with a 25 ppb internal standard added via automated standard addition.

Used Instrumentation

• Teledyne Tekmar Atomx Automated VOC Sample Prep System with in-vial purge and purge-and-trap concentrator
• Agilent 6890 GC equipped with J&W DB-VRX column (30 m × 0.25 mm i.d., 1.4 µm film)
• HP 5973 Mass Selective Detector (MSD) scanning 25–300 m/z

Main Results and Discussion

Total ion chromatograms revealed two clear regions: VOCs eluting between 2.5 and 10 min, and flavoring agents between 10 and 12 min. Six VOCs were consistently identified across samples: acetone, ethyl acetate, chloroform, bromodichloromethane, benzene, and styrene. Concentrations varied by brand and container type but remained below USEPA drinking water limits:

• Total trihalomethanes (chloroform + bromodichloromethane) were under the 80 ppb regulatory threshold, with chloroform <70 ppb.
• Benzene levels did not exceed the 5 ppb limit.
• Styrene measurements (1.1–1.8 ppb) were well below its 100 ppb advisory limit.
• Acetone and ethyl acetate were the predominant VOCs but lacked specific beverage regulations.

These findings confirm that automated in-vial purge minimizes matrix effects from sugars and carbonation, enabling reliable VOC quantification in beverages.

Benefits and Practical Application of the Method

The combined Atomx and GC/MS workflow offers several advantages for routine beverage testing:

• Efficient handling of complex matrices without transferring sugars or acids into the system.
• Automated calibration and standard addition ensure precision and compliance with USEPA performance criteria.
• Flexible platform supports multiple sample types (liquids, soils) and extraction modes.
• Reduced instrument downtime and maintenance due to in-vial cleanup.

Future Trends and Opportunities for Use

As consumer interest in product safety grows, the following developments are anticipated:

• Extension of in-vial purge techniques to other beverage categories (juices, teas, alcoholic drinks).
• Integration with high-resolution MS for non-target VOC screening.
• Miniaturized and portable purge-and-trap systems for on-site testing in production facilities.
• Enhanced automation and data interpretation using advanced software and machine learning.

Conclusion

The automated in-vial purge approach, combined with GC/MS, delivers robust VOC analysis in diverse beverage matrices. All tested sodas contained VOC levels below drinking water limits, demonstrating both method suitability and product safety. The described workflow provides laboratories with a versatile, high-throughput solution for volatile compound monitoring.

References

• Mary Ellen Fleming-Jones and Robert E. Smith. Journal of Agricultural and Food Chemistry. 2003;51:8120–8127.
• USEPA Method 8260C. Volatile Organic Compounds by Gas Chromatography/Mass Spectrometry. Revision 3, August 2006.
• USEPA Drinking Water Contaminants. U.S. Environmental Protection Agency website.