Distilled Spirit Analysis using the New 100 % Aqueous Stable Zebron™ ZB-WAXplus

Importance of the topic

Accurate analysis of volatile congeners in distilled spirits is essential for quality control, flavor profiling and fraud detection in the beverage industry. Traditional polyethylene glycol GC phases degrade upon water exposure, limiting direct analysis of high-water content samples. The new Zebron ZB-WAXplus column overcomes these limitations, offering a stable platform for repeated direct injections of aqueous matrices.

Objectives and overview of the study

This application note evaluates the performance of the Zebron ZB-WAXplus column for direct GC analysis of distilled spirits. Key aims include demonstrating phase stability, reproducibility of congener quantitation at low ppm levels and extended analysis to include fatty acid components in a single run.

Methodology and instrumentation

• Column: Zebron ZB-WAXplus, 30 m × 0.25 mm i.d., 0.25 µm film thickness
• Injection: 0.2 µL split 30:1 at 140 °C, direct injection of undiluted whiskey
• Carrier gas: Helium at 1.4 mL/min (constant flow)
• Oven program: 35 °C (5 min) to 85 °C at 10 °C/min, then to 200 °C at 25 °C/min (1 min hold)
• Detector: FID at 200 °C

Key results and discussion

Baseline resolution was achieved for critical congeners including acetaldehyde, ethyl acetate and methanol. Repeated injections showed relative standard deviations below 5 %, indicating excellent reproducibility despite 60 % water content. The low surface activity of the bonded phase allowed late-eluting fatty acids—such as butanoic and hexanoic acids—to be quantified in the same chromatographic run. The absence of acetic acid in the sample suggested proper storage and an intact bottle seal.

Benefits and practical applications of the method

• Direct, split injection of high-water content spirits without sample dilution or headspace preparation
• Extended column lifetime and reproducible retention for aqueous matrices
• Simultaneous quantitation of volatile congeners and fatty acids in one analysis
• Support for quality assurance, counterfeit detection and production troubleshooting in distilleries

Future trends and applications

Advances in robust bonded phases like Zebron ZB-WAXplus open pathways to direct GC analysis of other challenging aqueous and bio-matrix samples. Integration with automated sampling systems and coupling with mass spectrometry could further expand sensitivity and compound identification in food, environmental and clinical laboratories.

Conclusion

The Zebron ZB-WAXplus column delivers reliable aqueous stability, low analyte activity and consistent quantitation of volatile congeners and fatty acids in distilled spirits. Its performance addresses longstanding challenges in GC analysis of water-rich samples, streamlining workflows and enhancing data quality for beverage quality control.

References

1. Countryman S, Kelly K. Distilled Spirit Analysis using the New 100 %Aqueous Stable Zebron™ ZB-WAXplus. Phenomenex Inc.; GC TN-2025.