Determination of Halogenated Hydrocarbons, Benzene, and Derivatives in Drinking Water with the Agilent 8697 Headspace Sampler and Agilent 8890 GC System

Importance of the Topic

Ensuring the safety and compliance of drinking water requires reliable detection of volatile organic compounds, including halogenated hydrocarbons and benzene derivatives. These analytes are regulated in many national standards due to their toxicity and prevalence as water contaminants. Headspace sampling combined with gas chromatography offers a robust, sensitive, and relatively simple workflow suitable for routine analysis in environmental and QA/QC laboratories.

Objectives and Study Overview

This study validates the Chinese national method GB/T 5750.8-2022 for the determination of 27 halogenated hydrocarbons and 11 volatile organic compounds in drinking water. Two separate headspace GC configurations were tested:

• HS/GC with electron capture detection (ECD) for halogenated hydrocarbons
• HS/GC with flame ionization detection (FID) for benzene and its derivatives plus selected halogenated hydrocarbons

The goal was to demonstrate sensitivity, linearity, repeatability, detection limits, and recovery performance of an Agilent 8697 headspace sampler coupled to an Agilent 8890 GC.

Instrumentation

• Agilent 8697 Headspace Sampler
• Agilent 8890 Gas Chromatograph equipped with ECD and FID detectors
• Columns:
  
  • J&W DB-624 Ultra Inert (30 m×0.25 mm, 1.4 µm) for ECD
  • J&W DB-WAX (30 m×0.32 mm, 0.25 µm) for FID
• Software: Agilent OpenLab CDS 2.5

Methodology

Water samples were spiked with mixed standards and salted with NaCl for headspace equilibrium. Vials (20 mL) were equilibrated at 60–70 °C for 15 min with agitation. A 1 mL headspace loop injected sample into the GC.
ECD method for 27 compounds used a DB-624 column and a temperature program (40 °C hold, ramp to 100 °C at 10 °C/min, then to 230 °C at 25 °C/min).
FID method for 11 VOCs employed a DB-WAX column and a temperature program (40 °C hold, ramp to 45 °C and to 90 °C, then to 150 °C). Constant carrier flows and detector gas settings matched GB/T recommendations.

Main Results and Discussion

Column selection experiments showed coelution issues on Rtx-1701 and DB-1701 columns solved by using DB-624 Ultra Inert. Chromatograms displayed full baseline separation for all target compounds.

• Linearity: correlation coefficients (R²) > 0.998 for all halogenated hydrocarbons and > 0.9994 for VOCs.
• Repeatability: area RSDs of 0.53–5.49% (n=7) for halogenated hydrocarbons; < 1.7% for VOCs.
• Method Detection Limits: 0.001–0.345 µg/L for halogenated hydrocarbons; 0.05–0.63 µg/L for VOCs.
• Recoveries: 75.5–129.1% for halogenated hydrocarbons; 91.5–106.6% for VOCs.

All performance criteria meet or exceed GB/T 5750.8-2022 specifications.

Benefits and Practical Applications

This headspace/GC approach provides:

• High sensitivity and stability for trace-level monitoring.
• Rapid sample throughput with minimal preparation.
• Cost-effective operation compared to purge-and-trap systems.
• Compliance with national drinking water quality standards.

Future Trends and Opportunities

Emerging developments may include:

• Coupling headspace sampling with mass spectrometry for enhanced qualitative analysis.
• Further miniaturization and automation to increase throughput.
• Integration of real-time data analysis and AI-based peak identification.
• Extension to additional environmental matrices and broader compound classes.

Conclusion

The combination of the Agilent 8697 headspace sampler and the 8890 GC/ECD-FID system delivers reliable, sensitive, and reproducible analysis of regulated halogenated hydrocarbons and VOCs in drinking water. It fully satisfies GB/T 5750.8-2022 requirements and supports routine environmental monitoring and quality control applications.

References

• GB/T 5749-2022 Standards for Drinking Water Quality, State Administration for Market Regulation, P.R. China.
• GB/T 5750.8-2022 Standard Examination Methods for Drinking Water – Organic Parameters, AQSIQ and Standardization Administration, P.R. China.