Meeting the requirements of US and European water standards

Overview of Analytical Strategies for Emerging Water Contaminants

Ensuring safe water supplies requires monitoring an ever-expanding range of regulated and unregulated pollutants at trace levels. Recent advances in chromatography and mass spectrometry enable direct, high-throughput analysis of target and unknown compounds in drinking, surface, ground, and wastewater.

Regulatory Frameworks

• United States: Safe Drinking Water Act, EPA “Method 537/537.1” for PFAS; “Method 539” for hormones; “Method 8270D” for semivolatiles; “Method 557” for haloacetic acids; Unregulated Contaminant Monitoring Rule (UCMR3).
• Europe: Water Framework Directive (WFD) and its daughter directives set Environmental Quality Standards (EQS) for priority substances (metals, pesticides, PAHs, PFAS) and emerging contaminants; EU Drinking Water Directive (98/83/EC) defines Maximum Contaminant Levels.

Analytical Challenges

• Detect ultra-trace analytes (pg/L to ng/L) in complex, high-salt matrices without extensive sample preparation.
• Eliminate interferences, ensure chromatographic resolution of isomers, and maintain fast cycle times for high sample throughput.
• Combine targeted quantitation and non-targeted screening in a single workflow.

Key Methodological Advances

• Gas Chromatography-Mass Spectrometry (GC-MS/MS, GC-HRMS): Orbitrap-based platforms and advanced electron ionization (AEI) deliver sub-ppt detection of nitrosamines, PBDEs, and haloacetic acids with high resolution and mass accuracy.
• Liquid Chromatography-Mass Spectrometry (LC-MS/MS, LC-HRMS): Triple quadrupole and high-resolution Orbitrap systems achieve ng/L to pg/L quantitation of PFAS, hormones, pharmaceuticals, and disinfection by-products using targeted-SIM and parallel reaction monitoring (PRM).
• Ion Chromatography-High-Resolution Mass Spectrometry (IC-HRMS): Direct injection screening of haloacetic acids and trace anions with KOH eluent generation and electrolytic suppressors.
• Inductively Coupled Plasma Techniques (ICP-OES, ICP-MS): Argon gas dilution and collision/reaction cells enable direct trace metal analysis (EU WFD and EPA 200.8) in estuarine and waste waters without dilution.

Conclusions and Perspectives

Automated, overlap-mode chromatography coupled with high-resolution mass spectrometry or advanced triple quadrupole analysis allows routine quantitation of emerging contaminants at regulatory and sub-regulatory levels. The integration of online SPE, argon dilution, and intelligent data processing optimizes laboratory throughput, while providing robust, selective, and reproducible results. Future trends include expanded suspect and non-target screening, further miniaturization and automation of sample prep, and harmonization of global water quality methods.