Determination of BTEX and volatile organic compounds (VOCs) in drinking water by GC-MS/MS coupled to static headspace and solid-phase microextraction sampling

Significance of the Topic

Volatile organic compounds (VOCs) and BTEX (benzene, toluene, ethylbenzene, xylenes) are widespread environmental contaminants originating from fuels, industrial solvents and processing. Their low solubility in water and high volatility pose human health risks—including carcinogenicity—when present in drinking water. Global regulations (e.g. US SDWA, EU Directive 2008/105/EC) enforce stringent maximum contaminant levels, driving the need for sensitive, high-throughput analytical methods.

Objectives and Study Overview

This work compares two automated sampling techniques—static headspace (SHS) and solid-phase microextraction (SPME) Arrow—for quantifying chlorinated, brominated VOCs and BTEX in drinking water. Analytical performance is assessed on a Thermo Scientific TSQ 9000 triple-quadrupole GC-MS/MS platform, evaluating sensitivity, linearity, detection limits, repeatability, stability and carryover over extended sequences.

Methodology and Instrumentation

The system comprises a TRACE 1310 GC with a TraceGOLD TG-624SilMS column (20 m×0.18 mm×1.0 μm) and a TSQ 9000 MS/MS equipped with ExtractaBrite ion source and NeverVent technology. Hydrogen carrier gas and split/splitless injection were used. A TriPlus RSH autosampler performed SHS and SPME Arrow (carbon WR/PDMS fiber) sampling. SHS conditions included 25 min incubation at 80 °C with 2.5 mL syringe draws. SPME Arrow extraction used 20 min at 40 °C, 500 rpm agitation. Elution employed rapid oven ramps for ≤9 min run times. Data were processed in Chromeleon CDS 7.3 with t-SIM or SRM modes.

Main Results and Discussion

Chromatography delivered sharp, well-resolved peaks and low baseline noise. External calibration over 0.5–20 µg/L (VOCs) and 0.3–3 µg/L (BTEX) yielded R²>0.990, AvCF %RSD<9% (SHS) and <5% (SPME). Method detection limits (MDLs) ranged 0.01–0.13 µg/L; SPME Arrow was essential to reach 0.1 µg/L for vinyl chloride. Poor affinity of the fiber for difluorochloromethane limited its detection (MDL>20 µg/L). Over 48 h, retention times varied <0.04 min; area RSDs, quantifications and ion ratios stayed within ±15%. Carryover was <0.01% when empty vials bracketing samples were analysed.

Benefits and Practical Application of the Method

• Minimal sample preparation and fully automated extraction/enrichment.
• Compliance with global regulatory thresholds for VOCs and BTEX.
• High throughput enabled by fast GC ramps and overlapping injections.
• Flexibility to switch between SIM and SRM for screening or confirmatory analysis.

Future Trends and Potential Uses

• Integration of SMART autosamplers for consumable tracking and syringe/fiber identification.
• Adoption of next-generation detectors (e.g. XLXR) for extended dynamic ranges and lifetimes.
• Expansion to broader contaminant panels, including emerging halogenated organics.
• Linkage with laboratory information management systems (LIMS) for streamlined reporting and compliance.

Conclusion

The combination of SHS and SPME Arrow sampling on a Thermo Scientific TSQ 9000 GC-MS/MS delivers robust, sensitive, high-throughput analysis of BTEX and diverse VOCs in drinking water. The method meets stringent regulatory requirements, demonstrates exceptional stability and negligible carryover, and supports routine environmental monitoring and quality control.

Reference

• United States Environmental Protection Agency. Technical Overview of Volatile Organic Compounds.
• US EPA. Safe Drinking Water Act (SDWA).
• Council of the European Union. Directive 2008/105/EC.
• ASTM D6520-00. Standard Practice for SPME of Water and Headspace.
• ISO 11423-1:1997. Water Quality – Headspace GC for Benzene and Derivatives.
• ISO 10301:1997. Water Quality – Volatile Halogenated Hydrocarbons.
• Pawliszyn J. Theory of Solid-Phase Microextraction. J Chrom Sci. 2000.
• ISO 17943:2016. Water Quality – HS-SPME GC-MS for VOCs.
• Thermo Scientific TSQ 9610 GC-MS/MS System Brochure.
• Thermo Scientific TriPlus RSH SMART Robotic Sampling System Brochure.