Sustainable uncompromised performance: analysis of volatile organic compounds in drinking water with the ISQ 7610 GC-MS using HeSaver-H2 Safer technology

Significance of the Topic

Environmental laboratories must accurately detect and quantify volatile organic compounds (VOCs) in drinking water to comply with EPA regulations and protect public health. The growing demand for high-throughput testing, combined with periodic helium supply constraints, drives the need for methods that maintain analytical performance while reducing resource consumption.

Objectives and Study Overview

This study demonstrates a routine analytical workflow that satisfies U.S. EPA Method 524.4 for VOC analysis in drinking water by coupling a Teledyne Tekmar Atomx XYZ purge and trap system with a Thermo Scientific TRACE 1610 GC equipped with HeSaver-H2Safer carrier gas technology and an ISQ 7610 single quadrupole MS system. Performance metrics included calibration linearity, method detection limits, precision, minimum reporting levels, and long-term stability.

Methodology and Instrumentation

The workflow includes:

• Sample preparation: calibration standards (0.2–50 ppb) and internal/surrogate standards spiked into water.
• Purge and trap: 5 mL sample volume, nitrogen purge gas, controlled trap and cup temperatures, automated desorption and bake steps.
• Gas chromatography: TRACE 1610 GC with TraceGOLD TG-VMS column (20 m × 0.18 mm, 1 µm), helium at 0.3 mL/min, temperature ramp from 35 °C to 225 °C in under 16 minutes.
• Mass spectrometry: ISQ 7610 MS with ExtractaBrite ion source, full-scan m/z 35–260 (0.10 s dwell), optional SIM mode for enhanced selectivity.
• Carrier gas saving: HeSaver-H2Safer SSL inlet uses inexpensive pressurizing gas (nitrogen) for vaporization and limited helium for column flow, reducing helium use by up to four-fold.
• Data handling: Chromeleon CDS controlled both purge-trap and GC-MS for streamlined acquisition and reporting.

Key Findings and Discussion

All 75 target VOCs were chromatographically resolved with minimal water interference and consistent peak shapes. Calibration over 0.2–50 ppb met EPA linearity criteria (r² ≥ 0.995) without forced zero. Method detection limits ranged from 0.04 to 0.27 ppb with precision below 20% RSD. Minimum reporting levels at 1 ppb were confirmed within ±50% to +150% of true values. A 160-injection sequence (two days’ continuous operation) showed RSDs below 30% for all analytes, demonstrating robust long-term stability. Helium usage calculations validated a four-fold extension of cylinder life under method conditions.

Benefits and Practical Applications

The integrated system offers:

• Regulatory compliance: fully meets EPA Method 524.4 requirements for linearity, detection limits, precision, and reporting levels.
• High throughput: under 16 minutes per sample with minimal maintenance.
• Resource efficiency: significant reduction in helium consumption, lowering costs and mitigating supply issues.
• Operational simplicity: unified software control of purge-trap and GC-MS enhances laboratory productivity.

Future Trends and Opportunities

Adoption of carrier gas conservation technologies is expected to rise as laboratories face environmental and supply challenges. Further automation and expanded use of selected ion monitoring can improve selectivity and throughput. This approach may be extended to other water quality methods and environmental analyses, supporting sustainable, high-performance workflows.

Conclusion

The combination of Thermo Scientific HeSaver-H2Safer technology, the ISQ 7610 MS, TRACE 1610 GC, and Teledyne Tekmar Atomx XYZ purge and trap system provides a robust, sensitive, and sustainable solution for routine VOC analysis in compliance with U.S. EPA Method 524.4. This configuration ensures reliable performance, extended helium cylinder life, and efficient laboratory operation.

Instrumentation Used

• Teledyne Tekmar Atomx XYZ Purge and Trap system
• Thermo Scientific TRACE 1610 Gas Chromatograph with HeSaver-H2Safer SSL inlet
• Thermo Scientific ISQ 7610 Single Quadrupole Mass Spectrometer with NeverVent VPI and ExtractaBrite ion source
• TraceGOLD TG-VMS GC column (20 m × 0.18 mm, 1 µm film)
• Thermo Scientific Chromeleon CDS software, version 7.3

References

1. Ladak A., Jeffers T., Nutter A. Analysis of volatile organic compounds in drinking water according to U.S. EPA Method 524.4. Application Note 001236. Thermo Fisher Scientific.
2. Scollo G., Parry I., Cavagnino D. Addressing gas conservation challenges when using helium or hydrogen as GC carrier gas. Technical Note 001218. Thermo Fisher Scientific.
3. Thermo Fisher Scientific AppsLab Application Repository for EPA Method 524.4.
4. Thermo Fisher Scientific Helium Saver Calculator tool.