Determination of Benzene and its Derivatives in Water with the Agilent 8697 Headspace Sampler and 8890 GC

Importance of the topic

The determination of benzene and its derivatives in water is critical due to their toxicity, volatility, and stringent regulatory limits. Accurate monitoring ensures environmental safety and compliance with industrial and public health standards.

Objectives and Study Overview

This application note validates the Chinese standard HJ 1067-2019 for benzene and analogue analysis in water. Using the Agilent 8697 headspace sampler coupled to an Agilent 8890 GC with FID, the study assesses method performance including linearity, precision, detection limits, and recovery across eight target compounds.

Methodology

Samples and calibration standards were prepared by adding 3 g sodium chloride and 10 mL ultrapure water to 20 mL vials, then spiking with mixed standards at 10, 20, 50, 200, 500, and 2000 µg/L. Vials were equilibrated at 80 °C for 40 minutes with agitation. Headspace aliquots (1 mL) were injected into the GC-FID system operated under constant flow.

Used Instrumentation

• Agilent 8697 Headspace Sampler: loop size 1 mL; oven and loop temperature 80 °C; transfer line 100 °C; equilibration time 40 min; vial shake level 8; fill pressure 15 psi with nitrogen.
• Agilent 8890 GC with FID: HP-INNOWax column (30 m×0.32 mm, 0.5 µm); inlet 200 °C split 10:1; carrier gas nitrogen at 2 mL/min; oven program 40 °C (5 min) → 80 °C at 5 °C/min (5 min) → 200 °C at 30 °C/min (5 min); FID at 250 °C with H₂ 30 mL/min and air 300 mL/min.

Main Results and Discussion

• Linearity: correlation coefficients ≥ 0.9998 over 10–2000 µg/L.
• Precision: area RSD 1.3–2.4% (n=8); retention time RSD < 0.045%.
• Detection limits: MDLs ≤ 0.2 µg/L for all compounds.
• Recoveries: 99.1–101.7% at 200 µg/L spikes in tap water (n=6).
• Chromatography: excellent peak shapes and baseline separation of ethylbenzene, p-xylene, and m-xylene on the HP-INNOWax column.

Benefits and Practical Applications

This headspace GC-FID method provides a cost-effective, robust solution for routine environmental and industrial water testing. The inert flow path minimizes carryover, ensuring consistent peak quality. It supports QA/QC laboratories and environmental agencies in meeting regulatory requirements.

Future Trends and Applications

Ongoing developments in autosampler design, rapid temperature programming, and integration with mass spectrometry will improve sensitivity and throughput. Coupling with data analytics and remote monitoring platforms can further enhance environmental surveillance and decision-making.

Conclusion

The Agilent 8697 headspace sampler combined with the 8890 GC-FID meets the HJ 1067-2019 standard, delivering precise, sensitive, and reliable analysis of benzene and related compounds in water. The demonstrated performance supports its adoption for environmental monitoring and industrial quality control.

Reference

1. HJ 1067-2019. Water Quality—Determination of Benzene and its Analogues—Headspace/Gas Chromatography. China National Environmental Monitoring Station, Ministry of Ecology and Environment (December 2019).