An automated approach for the determination of gasoline range organics (GRO) in water by gas chromatography coupled with static headspace sampling

Significance of the Topic

Gasoline range organics (GRO) are volatile hydrocarbons (C6–C10) commonly found in groundwater and soil following spills and leaks. Accurate quantitation of GRO in water is essential for environmental monitoring, regulatory compliance and remedial action planning.

Objectives and Study Overview

The study aimed to evaluate the analytical performance—linearity, sensitivity, precision and robustness—of the Thermo Scientific TriPlus 500 Gas Chromatography Headspace Autosampler interfaced with the TRACE 1310 GC and Flame Ionization Detector (FID) for quantitative determination of GRO in water samples.

Methodology and Instrumentation

• Sample introduction by static headspace using TriPlus 500 HS autosampler with direct column connection.
• Gas chromatography on a TraceGOLD TG-1MS column (30 m × 0.32 mm × 3 µm) with Instant Connect SSL injector (split 20:1) and FID detection.
• Headspace conditions: 85 °C incubation, 30 min; 200 kPa vial pressurization; 1 mL loop volume.
• GC oven ramp from 50 °C to 220 °C at 15 °C/min, total runtime <13 min.
• Data acquisition and processing in Chromeleon CDS software with automated integration and reprocessing capabilities.

Main Results and Discussion

Linearity was excellent (R2 = 1.000) over 6.25–10 000 µg/L for nine GRO components. Average method detection limit (MDL) was 1.4 µg/L and limit of quantitation (LOQ) was 4.6 µg/L. Component recoveries in spiked tap water at 12.5 µg/L averaged 105%. System precision showed peak area RSDs of 0.91% (standards) and 1.1% (raw gasoline matrix) for ten consecutive injections. Matrix spikes at 1000 and 10 000 µg/L yielded recoveries between 89% and 116% (average 96%). Quantitation of spiked real samples using single-component and total peak area (EPA 8015 C and Wisconsin methods) followed by software integration demonstrated consistent results. No analyte carryover was detected in blank runs.

Benefits and Practical Applications

• Fully automated workflow from sampling to reporting enhances throughput and traceability.
• Minimal sample preparation and rapid analysis (<13 min) support high sample loads.
• High sensitivity and broad linear range enable detection of trace-level contamination.
• Robustness and inertness of the autosampler and column ensure reproducible results and low carryover.

Future Trends and Potential Applications

Advances in static headspace automation and integration with mass spectrometry are expected to further improve sensitivity, selectivity and data management. Expansion of in-field HS-GC platforms and real-time monitoring systems will enhance environmental surveillance. Coupling with LIMS and cloud-based analytics can streamline regulatory reporting and decision support in site remediation.

Conclusion

The combined Thermo Scientific TriPlus 500 HS autosampler and TRACE 1310 GC-FID system delivers a robust, sensitive and high-throughput solution for quantitative analysis of gasoline range organics in water. Its superior linearity, low detection limits, excellent precision and fully automated operation make it well suited for routine environmental laboratories.

Used Instrumentation

• TriPlus 500 Gas Chromatography Headspace Autosampler
• TRACE 1310 Gas Chromatograph with Instant Connect split/splitless injector and Flame Ionization Detector
• TraceGOLD TG-1MS GC column (30 m × 0.32 mm × 3 µm)
• Chromeleon CDS software v7.2

References

1. EPA Definition and Procedure for the Determination of the Method Detection Limit (MDL), Revision 2, 2016.
2. Wisconsin DNR Modified GRO Method for Determining Gasoline Range Organics, PUBL-SW-140, 1995.
3. EPA Method 8015 C Nonhalogenated Organics by Gas Chromatography, Revision 3, 2007.
4. Thermo Fisher Scientific Chromeleon CDS Enterprise Brochure, BR72617-EN0718S.