US EPA Method 624 with the Teledyne Tekmar Lumin P&T Concentrator, AQUATek LVA and Agilent 7890B GC/5977A MSD

Significance of the Topic

The reliable quantification of volatile organic compounds in wastewater is essential for environmental compliance and public health protection. Techniques that combine effective moisture removal and sensitive detection play a pivotal role in delivering accurate results at low concentration levels

Objectives and Study Overview

This study aimed to evaluate the performance of the Teledyne Tekmar Lumin purge and trap concentrator together with the AQUATek LVA autosampler and an Agilent 7890B GC/5977A MS system to determine 31 priority VOCs in wastewater according to US EPA Method 624. Key outcomes included development of a linear calibration curve and establishment of method detection limits

Methodology

Sample preparation involved spiking wastewater samples with internal and surrogate standards yielding final concentrations of 25 ppb. A calibration series ranging from 0.5 to 200 ppb was prepared in methanol. The Lumin concentrator performed automated purge and trap with optimized temperature and flow profiles while the AQUATek LVA provided precise sample introduction and moisture control. The GC was configured with an Rtx VMS column under a temperature program from 35 °C to 225 °C over 14 minutes and the MSD operated in scan mode (m/z 35 – 260)

Used Instrumentation

• Teledyne Tekmar Lumin Purge and Trap Concentrator with Moisture Control System
• AQUATek LVA Water‐Only Autosampler with XYZ Automation and Chiller‐Enabled Tray
• Agilent 7890B Gas Chromatograph equipped with Rtx VMS Column
• Agilent 5977A Mass Selective Detector operated in scan mode (m/z 35 – 260)

Main Results and Discussion

• Calibration linearity for all compounds achieved RSD values below 20%, meeting EPA requirements
• Method detection limits ranged from 0.05 to 0.17 ppb, enabling trace-level analysis of VOCs
• Accuracy in the 0.5 ppb test set ranged from 89% to 127% with precision RSD below 12%, confirming method robustness
• Moisture Control System reduced water vapor interference by up to 60%, preserving peak shape and extending column lifespan

Benefits and Practical Applications

• Enhanced sensitivity and low detection limits facilitate monitoring of regulated VOCs in wastewater
• Automated sample handling and moisture management increase laboratory throughput and reproducibility
• Modular instrumentation design allows adaptation to diverse environmental and industrial matrices

Future Trends and Potential Applications

• Integration with faster GC temperature programs to further increase sample throughput
• Extension of the approach to other water matrices and real-time monitoring applications
• Coupling with high-resolution mass spectrometry for expanded compound coverage and specificity

Conclusion

The combined Lumin purge and trap concentrator, AQUATek LVA autosampler and Agilent GC/MS system fulfills US EPA Method 624 requirements for VOC analysis in wastewater, offering reliable calibration, low detection limits and minimal water interference. Method optimization can further enhance throughput in routine laboratory workflows

Reference

1. Appendix A to Part 136 Methods for Organic Chemical Analysis of Municipal and Industrial Wastewater Method 624 Purgeables US EPA Promulgated 1984