Headspace Analysis of Chlorinated Solvents

Importance of Topic

Chlorinated solvents are pervasive environmental contaminants posing health risks even at trace levels. Rapid, sensitive analysis of these volatile compounds in water is crucial for regulatory compliance and protecting public health.

Objectives and Study Overview

This application note outlines a static headspace gas chromatography method for simultaneous separation and detection of ten chlorinated solvents in aqueous samples. The aim is to achieve baseline resolution within nine minutes and detect concentrations as low as 1 µg/L.

Methodology and Instrumentation

One milliliter of water sample was equilibrated at 80 °C in a headspace vial. Analysis was conducted on an Agilent 6890 GC equipped with an Agilent J&W CP-Sil 8 CB capillary column (0.32 mm x 25 m, 5 µm). The oven temperature was programmed from 40 °C (1 min) to 250 °C at 30 °C/min, followed by a 6-minute hold. Helium at 100 kPa served as the carrier gas. A split injection (20 mL/min) and an Electron Capture Halogen-Specific Detector (ELCD) operating at 280 °C provided selective detection.

Main Results and Discussion

The method successfully resolved ten target analytes—ranging from cis-1,2-dichloroethylene and chloroform to dichlorobenzenes—within a total analysis time of under nine minutes. Calibration curves were linear at the 1 µg/L level, and the ELCD’s halogen-specific response minimized interference from non-halogenated matrix components.

Benefits and Practical Applications

• Fast cycle times enhance laboratory throughput.
• Low detection limits meet environmental monitoring standards.
• Simple sample handling reduces preparation time and contamination risk.
• Selective halogen-mode detection improves analyte specificity in complex matrices.

Future Trends and Potential Applications

Emerging developments include fully automated headspace samplers and miniaturized GC systems that further decrease analysis time and sample volume. Coupling with mass spectrometry could broaden analyte scope and improve quantitation. Portable GC units may enable on-site monitoring of chlorinated contaminants.

Conclusion

The headspace GC-ELCD method offers a rapid, sensitive, and robust approach for routine quantification of chlorinated solvents in water, aligning with stringent environmental regulations and laboratory efficiency goals.

Used Instrumentation

• Gas chromatograph: Agilent 6890 GC
• Column: Agilent J&W CP-Sil 8 CB, 0.32 mm x 25 m, 5 µm
• Headspace sampler: static equilibration at 80 °C
• Detector: Electron Capture Halogen-Specific Detector (ELCD) at 280 °C

References

Agilent Technologies, Inc. Application Note A00720, Headspace Analysis of Chlorinated Solvents, first published May 11, 2010; updated June 19, 2014.