GC/HPLC Analyses of Organic Compounds in Drinking Water: US EPA Procedures

Significance of the Topic

Monitoring organic contaminants in drinking water is essential for public health, regulatory compliance, and ensuring the safety of municipal water supplies.

Objectives and Study Overview

This bulletin reviews US EPA Series 500 procedures for the analysis of volatile and semi-volatile organic compounds in drinking water. It outlines sample preparation techniques, chromatographic separation, detection strategies, and instrument configurations for each analyte class.

Methodology and Instrumentation

• Sample preparation: purge and trap for VOCs, solid phase extraction for semi-volatiles and pesticides, liquid-liquid extraction, and postcolumn derivatization for polar compounds
• Gas chromatography: capillary columns VOCOL, PTE-5, SPB-1 and SPB-1701 with detectors including photoionization, electrolytic conductivity, electron capture, nitrogen-phosphorus and mass spectrometry
• High-performance liquid chromatography: C18 and ion-exchange columns SUPELCOSIL LC-18 and Aminex A-9 with fluorescence or UV detection
• Purge-trap concentrators and SPE media such as VOCARB 4000 and ENVI-18 tubes and disks enhance analyte capture and cleanup

Main Results and Discussion

• Method 502.2 achieves sensitive GC/PID-ELCD separation of over 50 priority VOCs with robust thermal desorption and low background interference
• Method 524.2 uses GC/MS to confirm and quantify more than 60 purgeable organics at sub-ppb levels
• Microextraction GC/ECD (method 505) provides selective detection of halogenated pesticides and PCBs with low detection limits
• HPLC with postcolumn derivatization (methods 531.1 and 547) allows trace-level quantitation of carbamates, glyphosate, diquat and paraquat
• Methods for PAHs (550.1) and halogenated disinfection byproducts (551) offer effective monitoring of regulated and unregulated compounds

Benefits and Practical Applications

These standardized methods support compliance with maximum contaminant levels and unregulated contaminant monitoring. They facilitate risk assessment, treatment process optimization, and routine quality control in analytical laboratories.

Future Trends and Applications

• Adoption of advanced mass spectrometry such as GC-MS/MS and high-resolution MS for non-target screening
• Automated sample preparation and development of novel SPE materials to increase throughput
• Miniaturized, field-deployable GC and LC systems for real-time water monitoring
• Machine learning algorithms for rapid chromatographic data interpretation and anomaly detection

Conclusion

Combining EPA Series 500 protocols with modern instrumentation and consumables delivers reliable, high-throughput analysis of organic contaminants in drinking water. Continued innovation in separation and detection technologies will enhance water quality surveillance.

References

1. US Environmental Protection Agency Methods for Determination of Organic Compounds in Drinking Water Series 500 Order No PB91-231480
2. National Technical Information Service Technical Note for Drinking Water NTIS PB95-104766