US EPA Method 524.2 with the Teledyne Tekmar Lumin P&T Concentrator and Agilent 7890B GC / 5977A MS

Importance of the Topic

Volatile organic compounds (VOCs) at trace levels in drinking water present significant health and regulatory challenges. US EPA Method 524.2 is a standard approach for VOC analysis but often floods GC/MS systems with water vapor during desorption, leading to maintenance issues and compromised chromatographic performance. Innovations in purge-and-trap sample introduction can mitigate water transfer and enhance method reliability.

Objectives and Overview

This application note evaluates the performance of the Teledyne Tekmar Lumin Purge and Trap Concentrator with Moisture Control System (MCS) and AQUATek 100 sample preparation unit, coupled to an Agilent 7890B GC/5977A MS, under US EPA Method 524.2. Key goals include:

• Reducing water vapor load on the GC/MS system
• Maintaining target method detection limits (MDLs) and calibration linearity
• Improving sample throughput via enhanced trap cooling

Methodology

Calibration standards were prepared from Restek® Drinking Water VOA MegaMix, oxygenates, ketones and 502.2 mix. Ranges spanned 0.5–50 ppb for most analytes, 1.25–125 ppb for ketones and 2.5–250 ppb for t-butanol. Seven replicate 0.5 ppb samples established MDL, accuracy and precision. The analytical trap was desorbed for 4 minutes at 250 °C; the MCS bake at 200 °C limited water transfer. GC oven programming and MS scan settings followed EPA guidance.

Instrumentation Used

• Teledyne Tekmar Lumin P&T Concentrator with Moisture Control System
• AQUATek 100 sample preparation module
• Agilent 7890B gas chromatograph with 5977A mass spectrometer
• DB-624 UI capillary column (20 m × 0.18 mm, 1 µm film), helium carrier gas at 0.8 mL/min

Main Results and Discussion

• Calibration linearity RSDs were generally below 10%, meeting method criteria.
• MDLs ranged from 0.03 to 1.39 ppb across target VOCs.
• Accuracy at 0.5 ppb averaged 90–137%, precision RSDs were below 12% for most compounds.
• Chromatograms of 0.2 ppb and 5 ppb standards showed clear peak shapes with minimal water interference, especially for early-eluting gases.
• Enhanced trap cooling reduced sample cycle time, increasing throughput within a 12-hour workday.

Benefits and Practical Applications

• Minimized water load on GC/MS, extending column and inlet life and reducing MS source maintenance.
• Consistent trace-level VOC detection in compliance with US EPA 524.2.
• Improved laboratory efficiency through shorter cycle times and greater sample capacity.

Future Trends and Potential Use

Continued integration of advanced moisture control in purge-and-trap systems will support broader environmental monitoring, including real-time water quality assessment. Future developments may include coupling with high-resolution mass spectrometry, fully automated workflows and adaptation to diverse water matrices beyond finished drinking water.

Conclusion

The Lumin P&T Concentrator with Moisture Control System, combined with AQUATek 100 and Agilent 7890B/5977A GC/MS, effectively meets US EPA Method 524.2 requirements. It delivers reliable VOC analysis in drinking water by reducing water interference, preserving system performance and enhancing laboratory productivity.

Reference

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