Blood Alcohol Analysis on Rtx®-BAC Plus 1

Significance of the Topic

Reliable and rapid determination of blood alcohol content is a cornerstone in forensic toxicology, clinical diagnostics, and quality control laboratories. High-resolution separation of ethanol and related volatile compounds ensures accurate legal outcomes, patient safety, and process validation in industrial settings.

Objectives and Study Overview

The study aimed to evaluate the performance of the Rtx®-BAC Plus 1 capillary GC column for headspace analysis of blood alcohol. Key goals included achieving full resolution of critical analytes such as t-butanol and acetone, minimizing run time, and demonstrating clear separation of ethanol from co-eluting compounds.

Methodology

Standards of methanol, acetaldehyde, ethanol, isopropanol, acetone, t-butanol, and n-propanol were each prepared at 50–100 µg/mL in water. A 50 µL aliquot of each standard mixture was placed in a 20 mL headspace vial and equilibrated at 60 °C for 5 minutes. The headspace‐loop injector operated in split mode (50:1) with a loop fill time of 1 minute at 20 psi. The GC oven was held at 40 °C for 3 minutes, and the transfer line was maintained at 125 °C. Analysis was completed in under 3 minutes.

Used Instrumentation

• Column: Rtx®-BAC Plus 1 (30 m×0.32 mm ID, 1.8 µm film).
• Headspace Concentrator: Tekmar HT3.
• Gas Chromatograph: Agilent/HP 6890 equipped with FID at 240 °C.
• Carrier Gas: Helium, constant flow (80 cm/s at 40 °C); make-up gas nitrogen (30 mL/min).

Main Results and Discussion

The Rtx®-BAC Plus 1 column achieved baseline resolution of all seven target volatiles, including critical separation of t-butanol and acetone peaks. Ethanol eluted at 1.158 minutes with no interference. The total cycle time was under 3 minutes, demonstrating high throughput potential.

Benefits and Practical Applications

• Rapid turnaround for forensic and clinical cases where time is critical.
• High resolution reduces false positives/negatives in DUI testing.
• Simplified sample preparation via direct headspace analysis.
• Applicability in industrial QC for beverage and fermentation processes.

Future Trends and Potential Applications

Advances may include coupling fast GC with mass spectrometry for confirmatory analysis and automation of headspace sampling for higher throughput. Emerging column technologies could further shorten analysis times and improve sensitivity for trace-level volatile compounds.

Conclusion

The Rtx®-BAC Plus 1 column delivers rapid, fully resolved blood alcohol analysis with a total run time below 3 minutes. Its robust performance makes it ideal for forensic, clinical, and industrial laboratories requiring precise volatile quantification.