Halogenated hydrocarbons, C2 – C2 - Analysis of halogenated hydrocarbons in hydrocarbon/water matrix

Significance of the Topic

Volatile halogenated hydrocarbons are commonly found in environmental samples and industrial effluents. Accurate measurement of these compounds at low parts-per-million levels in complex hydrocarbon/water matrices is crucial for regulatory compliance, pollution control, and safety monitoring. Reliable analytical methods help laboratories maintain quality control and protect human health and ecosystems.

Objectives and Study Overview

This application note demonstrates a gas chromatography method for quantifying C1 and C2 halogenated hydrocarbons at 1–4 ppm in a 50 % hydrocarbon/50 % water matrix. The study aims to achieve baseline separation of target analytes, minimize co-elution with hydrocarbon components, and maintain accuracy within 5 % using an electrolytic conductivity detector (ELCD) and a polar porous polymer column.

Methodology

Sample analysis was performed using a wide-bore gas chromatograph with split injection. The column was operated isothermally at 150 °C. Helium served as carrier gas at 80 kPa (0.8 bar). Calibration standards of chloromethane, vinyl chloride, and chloroethane were prepared at 1, 2 and 3.5 ppm levels in a 50 % hydrocarbon/50 % nitrogen matrix. Detector response was evaluated in chloride mode.

Used Instrumentation

• Gas chromatograph with wide-bore inlet and split mode injector at 200 °C
• Agilent PoraPLOT U column, 0.53 mm × 25 m, 20 µm film (Part No. CP7584)
• Electrolytic Conductivity Detector (ELCD), chloride mode
• Reactor gas: hydrogen; reactor temperature: 850 °C; electrolyte: n-propanol

Main Results and Discussion

Baseline separation of the three analytes was achieved without interference from hydrocarbon matrix components. The PoraPLOT U column’s polar porous structure minimized co-elution and delivered sharp, well-resolved peaks. Detector response was linear across the 1–4 ppm range, with measurement accuracy better than 5 %. Retention times correlated consistently with concentration levels.

Benefits and Practical Applications

• Low detection limits for environmental monitoring of halogenated hydrocarbons
• Robust performance in complex hydrocarbon/water matrices
• High selectivity and accuracy for regulatory compliance
• Ease of method implementation in routine QA/QC laboratories

Future Trends and Applications

Advancements may include coupling this approach with mass spectrometric detection for enhanced identification, integrating automated sample preparation for higher throughput, and developing miniaturized, field-deployable GC systems. New stationary phases may further improve selectivity for emerging halogenated pollutants.

Conclusion

The described GC–ELCD method using a PoraPLOT U column provides a reliable, accurate, and reproducible approach for measuring C1 and C2 halogenated hydrocarbons in challenging hydrocarbon/water matrices. It meets stringent accuracy requirements and can be readily adopted by environmental and industrial laboratories.

Reference

Agilent Technologies, Inc. Halogenated Hydrocarbons, C2–C2: Analysis of Halogenated Hydrocarbons in Hydrocarbon/Water Matrix. Application Note A01324, October 31, 2011.