GC/MSD, Purge and Trap, GC/SQ
IndustriesEnvironmental
ManufacturerThermo Fisher Scientific, Teledyne LABS
Importance of the Topic
Accurate measurement of volatile organic compounds (VOCs) in environmental water and soil is essential for regulatory compliance, site assessment and protection of public health. US EPA Method 8260, combined with purge and trap techniques (5030, 5035), remains a widely adopted standard for trace-level VOC determination.
Study Objectives and Overview
This application note evaluates the performance of the Teledyne Tekmar Atomx XYZ purge and trap (P&T) system coupled to a Thermo Scientific TRACE 1310 gas chromatograph and ISQ 7000 mass spectrometer (MS) with an Advanced Electron Ionization (AEI) source. Key goals include:
- Establishing linear calibration curves in water (0.5–200 ppb) and soil (1–200 ppb).
- Determining method detection limits (MDLs) and assessing accuracy and precision at low-ppb levels.
- Demonstrating system robustness against moisture interference.
Applied Methodology and Instrumentation
Sample Preparation:
- 50 ppm multi-component calibration mix prepared in methanol (97 target VOCs).
- Water curve standards: 0.5–200 ppb; soil curve: 1–200 ppb.
- Internal standards: pentafluorobenzene, 1,4-difluorobenzene, chlorobenzene-d5, 1,4-dichlorobenzene-d4.
- Surrogate standards: dibromofluoromethane, 1,2-dichloroethane-d4, toluene-d8, 4-bromofluorobenzene.
- MDL samples: ten 1 ppb (water) and ten 2 ppb (soil) replicates.
Applied Instrumentation:
- Teledyne Tekmar Atomx XYZ P&T system with moisture control and rapid trap cooling.
- Thermo Scientific TRACE 1310 GC: Rtx-VMS column, helium carrier, optimized temperature program.
- Thermo Scientific ISQ 7000 MS with AEI source: full-scan mode 35–260 amu.
Main Results and Discussion
Calibration curves exhibited relative standard deviations (RSD) below 20% for all target analytes. MDLs ranged typically from 0.1 ppb to 0.7 ppb in water and 0.2 ppb to 1 ppb in soil. Accuracy across ten replicates fell within 86–130%, and precision RSDs remained under 20%. Chromatograms of 100 ppb standards showed sharp, well-resolved peaks with negligible water interference, affirming the effectiveness of the moisture control system.
Benefits and Practical Applications
This configuration delivers:
- High sensitivity at sub-ppb levels, meeting EPA method requirements.
- Improved sample throughput—up to 14% faster cycle times due to efficient trap cooling.
- Enhanced reliability with reduced valve leak potential and extended GC column life.
- Flexible multi-matrix analysis (water and soil) in a single autosampler.
Future Trends and Applications
Emerging developments may include further miniaturization of P&T modules, integration of real-time data analytics, expanded use of advanced ionization techniques for broader compound coverage, and accelerated GC temperature programs to boost laboratory throughput.
Conclusion
The combined Atomx XYZ P&T and TRACE 1310 GC/ISQ 7000 MS system reliably fulfills US EPA Method 8260 requirements for water and soil VOC analysis. It achieves low MDLs, strong linearity, and robust accuracy and precision while enhancing laboratory efficiency and instrument longevity.
References
1. EPA SW-846 Method 8260C, Revision 3, August 2006
2. EPA SW-846 Method 8260D, Revision 4, February 2017
3. EPA SW-846 Method 5030B, Revision 2, December 1996
4. EPA SW-846 Method 5030C, Revision 3, May 2003
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