USEPA Procedures for Wastewater Analyses by Packed Column GC and HPLC

Importance of the Topic

Monitoring organic priority pollutants in wastewater is essential for environmental protection and regulatory compliance. Trace levels of volatile and nonvolatile contaminants pose risks to ecosystems and public health. Robust analytical methods ensure accurate quantification, support permit applications, and guide treatment strategies.

Objectives and Study Overview

This article reviews the USEPA validated procedures for analyzing 113 organic priority pollutants in wastewater. It summarizes the scope and organization of EPA Methods 601–613 (GC) and 624–625 (GC-MS), as well as HPLC Method 605, highlighting the division of analytes into classes (volatiles, acids, base-neutrals, pesticides, PCBs, phenols, nitrosamines, phthalates, haloethers, chlorinated hydrocarbons, PAHs, and TCDD isomers).

Methodology and Key Steps

The analytical workflow comprises two main concentration approaches:

• Purge-and-trap for volatile organics (Methods 601, 602, 603, 624): sample purging onto multilayer sorbent traps, thermal desorption, and GC or GC-MS separation.
• Solvent extraction for nonvolatile organics (Methods 604–613, 625): methylene chloride extraction, Kuderna-Danish concentration to 1 mL, sodium sulfate cleanup, optional Florisil or silica gel cleanup for matrix reduction.

Chromatographic separations use packed stainless-steel columns with deactivated stationary phases or capillary fused-silica equivalents. GC-MS Methods 624 (volatiles) and 625 (nonvolatiles) replace older packings with more inert phases for improved detection. HPLC is applied to polar analytes (benzidines, PAHs) using reversed-phase columns and UV or electrochemical detection.

Used Instrumentation

• Gas chromatograph with packed or capillary columns and temperature-programmed ovens.
• Mass spectrometer for EPA Methods 624, 625 and confirmation of suspect peaks.
• Flame ionization, electron-capture, photoionization, and Hall electroconductivity detectors.
• HPLC systems with UV and fluorescence detectors for PAHs, benzidines.
• Purge-and-trap concentrators and Kuderna-Danish solvent concentrators.
• Sorbent traps: Tenax, Carbopack, Silica Gel, Charcoal layers.

Main Results and Discussion

Supelco packings and columns are listed or accepted as generic equivalents in all relevant EPA methods. Improved deactivation in newer phases reduces peak tailing and enhances sensitivity at low nanogram levels. Capillary columns (SPB-5, SPB-608, VOCOL) demonstrate faster analysis, greater capacity, and compatibility with purge-trap systems, offering alternatives to packed columns when QC criteria are met.

Benefits and Practical Applications

• Validated procedures support compliance with NPDES permit requirements.
• Flexibility allows industries to select GC, GC-MS, or HPLC methods based on their capabilities.
• Wide analyte coverage addresses volatile, semi-volatile, acidic, and neutral compounds in a single framework.
• Use of generic equivalent packings reduces cost and ensures method continuity.

Future Trends and Applications

Advances in capillary and wide-bore fused-silica column technology will further decrease run times and improve resolution. Enhanced sorbent materials and automated purge-trap systems will boost sensitivity and throughput. Hyphenated techniques such as GC-FTIR and tandem mass spectrometry promise greater selectivity, while miniaturized and on-site analyzers may enable real-time monitoring.

Conclusion

The USEPA Methods 601–613 and 624–625, complemented by HPLC protocols, provide comprehensive, validated strategies for priority pollutant analysis in wastewater. Adoption of optimized packings, traps, and detectors ensures accurate, reproducible results across diverse industrial applications.

References

1. USEPA Effluent Guidelines Division. Sampling and Analysis Procedures for Screening of Industrial Effluents for Priority Pollutants. EPA, 1977.
2. USEPA. Federal Register, Vol. 44, No. 233, Dec. 3, 1979.
3. USEPA. Federal Register, Vol. 45, No. 98, May 19, 1980.
4. Bellar TA, Lichtenberg JJ. Purge-and-Trap Method for Volatile Organics. J. Am. Water Works Assoc. 66:739–744, 1974.
5. USEPA Health Effects Research Laboratory. Manual of Analytical Methods for the Analysis of Pesticides in Human and Environmental Samples. EPA-600/8-80-038, 1980.