US EPA Method 524.4 with the Tekmar Lumin P & T Concentrator and Thermo Scientific™ TRACE™ 1310 GC and ISQ™ LT MS System

Significance of the Topic

This application note addresses a common challenge in environmental analysis of drinking water: the determination of trace volatile organic compounds (VOCs) by purge and trap gas chromatography–mass spectrometry (P&T GC-MS). Excessive water vapor introduced during sample preparation degrades chromatographic performance and accelerates instrument maintenance, underscoring the need for efficient moisture control.

Objectives and Study Overview

The primary goal was to evaluate Teledyne Tekmar’s Lumin purge and trap concentrator, featuring an integrated moisture control system (MCS), for compliance with US EPA Method 524.4. The study compared water vapor load and analytical performance against conventional P&T systems when detecting VOCs in spiked drinking water samples at low‐ppb levels.

Methodology and Instrumentation

Water samples were prepared using Restek® 524.3 VOA MegaMix® standards, spanning calibration points from 0.2 ppb to 50 ppb. Internal standards and surrogates ensured accurate quantitation. Method detection limits (MDLs), accuracy and precision were determined from seven replicates at 0.5 ppb.

Used Instrumentation

• Teledyne Tekmar Lumin P&T concentrator with Moisture Control System
• Teledyne Tekmar AQUATek 100 autosampler
• Thermo Scientific TRACE 1310 GC with Rtx-VMS capillary column (20 m × 0.18 mm ID, 1 µm film)
• Thermo Scientific ISQ LT single quadrupole mass spectrometer
• Helium carrier gas (0.8 mL/min) and nitrogen purge gas

Main Results and Discussion

Calibration curves exhibited excellent linearity (r2 ≥ 0.993) across all VOCs. MDLs ranged from 0.03 ppb to 0.19 ppb, with recoveries between 86 % and 107 % and precision (RSD) below 12 %. Chromatograms of 0.2 ppb and 5 ppb standards showed sharp, well-resolved peaks for early‐eluting compounds with minimal water interference, confirming the MCS efficacy in reducing water vapor transfer.

Benefits and Practical Applications

• Reduced water load extends GC column and inlet lifetime, decreases MS source cleaning frequency
• Enhanced sensitivity and reproducibility at trace concentration levels
• Shorter sample cycle times increase laboratory throughput
• Compliance with regulatory requirements for drinking water analysis

Future Trends and Potential Applications

Advances may include integration of high-throughput autosamplers and coupling with high-resolution MS for screening additional environmental contaminants. Further development of moisture management technologies could enable more complex matrices and on-site field analysis.

Conclusion

Teledyne Tekmar’s Lumin P&T concentrator with moisture control, coupled to a Thermo TRACE 1310 GC-ISQ LT MS system, delivers robust compliance with US EPA Method 524.4. The system minimizes water interference while achieving low‐ppb detection, high accuracy and precision, and improved operational efficiency.

Reference

1. US EPA Method 524.4 Measurement of Purgeable Organic Compounds in Water by Capillary Column GC/MS Using Nitrogen Purge Gas, Office of Water, May 2013.