Evaluation of a New Analytical Trap for Gasoline Range Organics Analysis

Importance of the Topic

Gasoline range organics (GRO) are key environmental contaminants monitored in water and soil. Accurate trace-level detection of volatile hydrocarbons such as MTBE and BTEX is critical for regulatory compliance and environmental risk assessment.

Objectives and Study Overview

This study evaluates the performance of Teledyne Tekmar’s new #11-VPH-Trap across three analytical platforms to improve recovery and reduce methanol interference in GRO analysis using purge & trap and headspace techniques combined with GC/FID.

Methodology and Instrumentation

• Systems Tested: Atomx automated VOC prep with U-shaped trap, Velocity XPT purge & trap with AQUATek 100 autosampler, and HT3 headspace analyzer.
• Chromatography: Agilent 6890 GC with FID, Restek RTX-VMS column.
• Parameters: Specific P&T and GC temperature, flow, and timing conditions optimized for water, soil, and methanol extraction applications.

Key Results and Discussion

• Calibration Linearity: 5–200 ppb GRO standards showed excellent linearity (r² ≥ 0.9978–0.9999) across all systems.
• Detection Limits: LODs ranged from 1.22 ppb to 1.854 ppb; LOQs from 3.90 ppb to 5.89 ppb, meeting Wisconsin GRO criteria.
• Quality Control: RLCS and DLCS recoveries between 86.1 % and 105.1 % with RSDs below 4.2 %.
• Methanol Retention: #11-VPH-Trap retained significantly less methanol than competing traps, preventing overlap with MTBE peak at low ppb levels.
• Bake-Back Pressure: The #11-VPH-Trap showed stable bake pressure comparable to the #9 trap and outperformed the M-Trap, indicating longer trap lifetime.

Benefits and Practical Applications

The #11-VPH-Trap enables reliable quantitation of GRO compounds down to 5 ppb on multiple sample prep platforms, reduces solvent interference, and lowers operational costs by extending trap service life.

Future Trends and Applications

Emerging demands for lower detection limits and broader compound screening will drive further trap material innovations. Integration with advanced GC–MS and real-time monitoring systems could expand applications in field-based environmental analysis and industrial process control.

Conclusion

The Teledyne Tekmar #11-VPH-Trap delivers improved methanol handling, robust calibration performance, and extended trap longevity, making it an effective solution for trace-level GRO analysis in environmental laboratories.

References

• Modified GRO Method for Determining Gasoline Range Organics, Wisconsin DNR, September 1995, PUBL-SW-140.