US EPA Method 524.4 using the Teledyne Tekmar Atomx XYZ and Thermo Scientific™ ISQ™ 7000 Mass Spectrometry (MS) System Coupled with a Thermo Scientific™ TRACE™ 1310 Gas Chromatograph (GC)

Importance of the Topic

Ensuring the safety of drinking water requires sensitive and reliable detection of trace volatile organic compounds. US EPA Method 524.4 is a recognized protocol for quantifying VOCs in water. Combining optimized purge and trap sample preparation with high-performance GC-MS instrumentation enhances sensitivity, reduces interference, and increases sample throughput.

Objectives and Study Overview

This study evaluates the performance of the Teledyne Tekmar Atomx XYZ purge and trap system in conjunction with a Thermo Scientific TRACE 1310 gas chromatograph and ISQ 7000 mass spectrometer. The primary goals are to:

• Establish calibration linearity across 0.2–50 ppb for 75 target VOCs
• Determine method detection limits (MDLs) and minimum reporting levels (MRLs)
• Perform an initial demonstration of capability (IDC) to assess precision and accuracy

Methodology and Instrumentation

Calibration standards were prepared from Restek VOA Mega Mix and Gas Calibration Mix. Three internal standards and three surrogates ensured quantitative reliability. Replicate analyses at 0.5 ppb and 5 ppb levels provided data for MDL, MRL confirmation, and IDC evaluations. All procedures adhered strictly to EPA Method 524.4 parameters for purge, trap, desorb, and GC-MS operation.

Instrumentation Used

• Teledyne Tekmar Atomx XYZ Purge and Trap System with 84-position autosampler and advanced moisture control
• Thermo Scientific TRACE 1310 Gas Chromatograph with TG VMS column
• Thermo Scientific ISQ 7000 Single Quadrupole Mass Spectrometer

Main Results and Discussion

The method demonstrated:

• Excellent calibration linearity (r² ≥ 0.995) for all compounds
• MDLs below 0.15 ppb on average, meeting regulatory requirements
• IDC results with precision and accuracy within ±20% at 5 ppb
• Minimal interference from water vapor due to the Atomx XYZ’s moisture control
• Analysis throughput of up to three samples per hour

Benefits and Practical Application

This configuration delivers robust, reproducible VOC analysis with reduced maintenance demands. High sample throughput and reliable performance make it ideal for environmental monitoring labs, QA/QC operations, and regulatory compliance testing.

Future Trends and Opportunities

Anticipated developments include further miniaturization of purge and trap modules, integration of automated data processing and quality control software, and expansion of the method to semi-volatile and emerging contaminant classes. Refining GC oven programs could further boost analytical throughput.

Conclusion

The Atomx XYZ purge and trap system coupled with the TRACE 1310 GC and ISQ 7000 MS meets and exceeds US EPA Method 524.4 requirements. It achieves low detection limits, high accuracy, and efficient processing of drinking water samples, thereby enhancing laboratory capacity for VOC monitoring and compliance.

Reference

Munch, D.J.; Wendelken, S.C. Measurement of Purgeable Organic Compounds in Water by Gas Chromatography/Mass Spectrometry Using Nitrogen Purge Gas; US EPA Method 524.4, May 2013.