US EPA Method 524.2 with the Teledyne Tekmar Atomx XYZ and Thermo Scientific™ TRACE™ 1310 GC and ISQ™ 7000 MS System with an Advanced Electron Ionization (AEI) Source

Importance of the Topic

Volatile organic compounds in drinking water pose health and regulatory concerns at trace level concentrations. US EPA Method 524.2 offers a reliable approach for concentrating and detecting a broad range of purgeable VOCs, but handling excess water vapor during desorption remains a challenge. An effective moisture control system and advanced ionization source can improve sensitivity, reduce interference and extend instrument lifetime, making this approach vital for environmental monitoring and water quality assurance.

Objectives and Study Overview

This application note evaluates the performance of the Teledyne Tekmar Atomx XYZ purge and trap system coupled with a Thermo Scientific TRACE 1310 GC and ISQ 7000 MS equipped with an advanced electron ionization source. The goals include establishing linear calibration curves across 0.2 to 50 ppb, determining method detection limits, and assessing accuracy and precision for 82 target VOCs under US EPA Method 524.2 conditions.

Methodology

Sample Preparation

• Prepared a 25 ppm mixed standard in methanol containing 82 VOCs from drinking water, ketone and calibration mixes
• Calibration levels spanned 0.2 to 50 ppb with fluorobenzene as internal standard
• Surrogate standards included 4-bromofluorobenzene and 1,2-dichlorobenzene-d4, fortified at 25 ppb
• Ten replicate 0.5 ppb samples were analyzed for MDL, accuracy and precision

Purge and Trap Conditions

• Atomx XYZ desorb time 4 minutes at 250 C with helium purge
• Innovative moisture control removed up to 60 percent of water vapor prior to GC transfer
• Efficient trap cooling reduced cycle time by about 14 percent versus previous model

GC MS Conditions

• TRACE 1310 GC with Rtx VMS column, 20 m 0.18 mm, 1 micrometer film; helium carrier at 0.8 mL per minute
• Oven program: 35 C hold 2 min then ramps of 12 C per min to 85 C and 20 C per min to 225 C; total run time approx 15.2 minutes
• ISQ 7000 MS operating scan range 35 to 260 amu, transfer line 300 C, source 280 C

Instrumentation

The system comprised a Teledyne Tekmar Atomx XYZ purge and trap concentrator with an 84-position soil and water autosampler, a Thermo Scientific TRACE 1310 GC, and an ISQ 7000 MS fitted with an advanced electron ionization source.

Main Results and Discussion

• Calibration linearity met method criteria with relative standard deviations of response factors below 20 percent for all compounds.
• MDLs ranged from low parts per trillion to sub ppb levels, demonstrating high sensitivity.
• Accuracy and precision for ten 0.5 ppb replicates fell within method limits of ±20 percent and RSD ≤ 20 percent, with minimal water interference visible in chromatograms.
• A representative 50 ppb total ion chromatogram showed sharp, well resolved peaks and suppressed moisture background.

Benefits and Practical Applications

• Effective water vapor removal minimizes column degradation and peak distortion
• Reduced sample cycle time increases throughput for high volume labs
• Reliable quantitation at trace levels supports regulatory compliance and water safety monitoring
• Scalable to diverse environmental matrices beyond drinking water

Future Trends and Potential Applications

Advances in automated P&T and GC instrumentation may further shorten analysis times and integrate online data processing. Coupling with high resolution MS or alternative ionization techniques could expand target analyte scope. Remote monitoring and smart diagnostic features are likely to enhance laboratory efficiency and quality assurance in environmental testing.

Conclusion

The Atomx XYZ purge and trap in combination with the TRACE 1310 GC and ISQ 7000 MS with advanced electron ionization meets US EPA Method 524.2 requirements. It delivers robust moisture control, precise quantitation of VOCs in water at sub ppb levels, and potential for improved throughput through optimized temperature programming.

References

• Munch JW, US EPA Method 524.2 Measurement of Purgeable Organic Compounds in Water by Capillary Column Gas Chromatography Mass Spectrometry Revision 4.1 1995