EPA 601/602 Analysis using the EA-600

Importance of the Topic

Monitoring volatile organic compounds in water and understanding polymer formulations are critical tasks in environmental analysis and materials science. The EPA methods 601 and 602 address regulatory requirements for detecting halogenated and aromatic pollutants at low parts-per-billion levels, ensuring water safety. Meanwhile, coupling gel permeation chromatography with infrared detection (GPC-IR) provides formulators with in-depth insight into polymer composition and additive structure, supporting quality control and competitive product development.

Study Objectives and Overview

This application note combines two analytical challenges:

• Implementation of EPA methods 601/602 via purge-and-trap GC using a CDS Analytical EA-600 system equipped with both conductivity (ELCO) and photoionization (PIO) detectors.
• Characterization of a complex polymer mixture from silver ink paste using GPC-IR hyphenated technology to identify major polymer components and latent cross-linkers.

Methodology and Instrumentation

Purge-and-Trap GC (EPA 601/602):

• Sample: 5 mL water spiked to 20 ppb per analyte.
• Purge: Helium at 38 cc/min for 11 min onto a Tenax–Silica Gel–Charcoal trap.
• Desorb: Backflush trap at 280 °C onto a 105 m RTX Volatiles column (0.53 mm ID).
• Detection: Series arrangement of Tremetrics PIO and HALL ELCO detectors for aromatic and halocarbon analysis.
• GC Program: 25 °C hold 10 min, ramp 4 °C/min to 200 °C, hold 5 min.

Gel Permeation Chromatography–Infrared (GPC-IR):

• Separation of polymer fractions by molecular weight.
• Full FT-IR range capture to resolve monomeric polyester and polyurethane resins, latent cross-linkers, and blocked isocyanate additives.
• Database search for IR band matching and structural assignment.

Main Results and Discussion

EPA 601/602 Analysis:
Chromatograms confirmed baseline separation and reliable detection of 29 halocarbons and four aromatic compounds. The combined ELCO/PIO detector setup yielded clear peak profiles at 20 ppb, demonstrating method robustness.

Polymer Ink Characterization:
Three main polymers were identified:

• Polymer A: Aliphatic polyester resin (Amoco or similar), high Mw and broad distribution, strong adhesion.
• Polymer B: Aliphatic polyurethane (Sensorsol L-53), medium Mw, elastomeric properties, cross-linkable with tri-functional isocyanates.
• Component C: Latent cross-linker Desmodur LS-2800, stable at room temperature.

Additive C (blocked HDI trimer) was confirmed by its characteristic IR bands (CAS 93919-05-2, MW 766 g/mol). The hyphenated GPC-IR approach linked molecular weight fractions to chemical functionality, revealing an interpenetrating polymer network structure critical for conductive ink performance.

Benefits and Practical Applications

• Purge-and-trap GC provides regulatory compliance for water testing and streamlined environmental monitoring workflows.
• GPC-IR offers formulators a powerful tool to verify polymer architecture, cross-linker identity, and additive compatibility without extensive sample preparation.
• Combined approaches enhance QA/QC in industrial analytics and support intellectual property protection.

Future Trends and Opportunities

Advances may include integration of mass spectrometric detection with purge-and-trap systems, AI-driven spectral deconvolution in GPC-IR, portable purge-and-trap modules for field testing, and expanded polymer spectral libraries to accelerate formulation development.

Conclusion

The combined use of EPA purge-and-trap GC methods and GPC-IR hyphenated analysis enables comprehensive chemical characterization across environmental and materials applications. These techniques deliver sensitive detection of trace contaminants and detailed insight into complex polymer blends, supporting regulatory compliance and product innovation.

References

• J.J. Keller & Associates, Air and Water Pollution: A Guide to Federal Regulations.
• J.W. Washall, T.P. Wampler, Sources of Error in Purge and Trap Analysis of Volatile Organic Compounds, American Lab, 22(18), 38–44 (1990).
• J.W. Washall, CDSolutions: Reproducibility in Automated Environmental Purge and Trap, CDS Analytical.