Analysis of Blood Alcohol Content with the 120-Vial Agilent 8697 Headspace Sampler -XL Tray and Dual-FID Agilent 8890 GC System

Importance of the Topic

Blood alcohol content (BAC) analysis is a cornerstone of forensic toxicology and traffic safety enforcement. Accurate, rapid, and reliable quantification of ethanol in blood is essential for legal determinations and public safety. Headspace gas chromatography with flame ionization detection (HS-GC-FID) is widely adopted due to its minimal sample preparation, high selectivity for volatile compounds, and protection of column integrity from nonvolatile matrix components.

Objectives and Study Overview

This study evaluates a high-throughput HS-GC-FID workflow coupling the Agilent 8697 Headspace Sampler with an expanded 120-vial tray (XL Tray) to the Agilent 8890 GC system configured with dual columns (DB-BAC1 Ultra Inert and DB-BAC2 Ultra Inert) and dual FIDs. Key performance metrics include linearity across typical forensic BAC ranges, reproducibility, carryover, and overall cycle time to address laboratory backlogs.

Instrumentation

The analytical setup comprises:

• Agilent 8697 Headspace Sampler – XL Tray (120-vial capacity) with heat-traced transfer line
• Agilent 8890 GC with split/splitless inlet
• Two Agilent J&W columns: DB-BAC1 UI (primary) and DB-BAC2 UI (confirmatory)
• Dual FIDs for simultaneous detection
• Internal standard: n-propanol

Methodology

Samples consisted of 450 µL internal standard solution (0.1% n-propanol) and 50 µL blood or calibration standard in 20 mL vials. Headspace conditions: 70 °C oven, 80 °C loop, 7 min equilibration, 1 min injection. GC conditions: 150 °C inlet, helium carrier at constant pressure (21 psi), split 10:1, isothermal oven at 40 °C for 5 min. Cycle time was optimized to 6 min to balance throughput with chromatographic resolution.

Main Results and Discussion

Calibration across 0.025–0.3% ethanol showed excellent linearity (R²>0.9999 on both FIDs). Repeatability tests with a 12-compound blood alcohol checkout mix at 50 mg/dL yielded retention time RSD <0.05% and area RSD <2.1%. Carryover assessment at 0.4% ethanol demonstrated no detectable residual peaks in subsequent blanks. System robustness was confirmed by consistent peak shapes and resolution across both columns.

Benefits and Practical Applications

This dual-column, dual-FID HS-GC approach provides:

• High sample throughput (up to 10 samples per hour)
• Minimal sample prep and low maintenance
• Robustness against matrix effects and reduced column fouling
• Simultaneous primary and confirmatory analyses for forensic compliance

Future Trends and Potential Applications

Advancements may include integration with laboratory information management systems for automated data processing, expansion to other volatile forensic analytes (e.g., ketones, drugs), and miniaturized headspace modules for point-of-care toxicology.

Conclusion

The Agilent 8697 HS Sampler XL Tray combined with the 8890 GC dual-FID configuration delivers fast, precise, and carryover-free BAC analysis, supporting forensic laboratories in meeting high throughput demands without compromising analytical performance.

References

• Agilent Technologies. Blood Alcohol Analysis with the Integrated Agilent 8697 Headspace Sampler on 8890 GC-Dual FID System, Application Note 5994-3126EN, 2022.