The Measure of Purity - Water quality applications

Importance of the Topic

Water is an essential resource under constant threat from chemical contamination and emerging pollutants. Regulatory agencies worldwide monitor water quality to protect public health and the environment. Analytical methods capable of identifying organic and inorganic contaminants at trace levels are critical to ensure compliance with evolving water quality standards and to safeguard drinking water, surface water, and wastewater sources.

Objectives and Overview of the Article

This application overview presents a comprehensive portfolio of Agilent’s analytical solutions for water quality testing. It spans volatile organic compounds (VOCs), semivolatiles, pesticides, herbicides, emerging contaminants, and elemental analysis. The goal is to demonstrate high sensitivity, throughput, robustness, and regulatory compliance across multiple instrumental platforms.

Methodology and Instrumentation

Analytical workflows employ optimized sample preparation, separation, and detection techniques:

• Gas chromatography with headspace sampling (Agilent 7697A) and selected-ion monitoring GC/MSD (Agilent 8890/5977A) for VOCs at parts-per-trillion levels, meeting EU 98/83/EC requirements.
• Purge and trap autosamplers (Teledyne Tekmar Lumin P&T, AQUATek LVA, Atomx XYZ) coupled to GC/MSD (Agilent 7890/5977B) for US EPA Method 524.2 analysis of 71 VOCs in 15 minutes, achieving low-ppt LODs.
• Single-quadrupole and triple-quadrupole GC/MS (Agilent 7000D) for semivolatiles, pesticides, PAHs, and flame retardants, with multimode inlets, capillary flow backflush, and comprehensive MRM databases to reduce interferences.
• LC/MS/MS platforms (Agilent 6400/6490/6460/6495 triple quadrupoles and Ultivo) coupled to InfinityLab Online SPE or direct injection for trace herbicide, PPCP, and PFAS quantitation at ng/L-level LOQs, supported by tMRM pesticide libraries.
• High-resolution GC/Q-TOF (Agilent 7250) and LC/Q-TOF (Agilent 6500) for non-target screening, structural elucidation of unknowns, sub-ppm mass accuracy, and isotopic fidelity.
• Elemental analysis by AAS (Agilent 280Z Zeeman GFAA, 240 AA with VGA 77), MP-AES (Agilent 4210), ICP-OES (Agilent 5110 SVDV), and ICP-MS (Agilent 7800/7900 with ISIS 3 and prepFAST) for multi-element quantitation from percentages to ppt levels.
• UV-Vis spectrophotometry (Agilent Cary 60 with dip probe) for rapid ion analysis (nitrates, phosphates).
• Sample preparation and consumables: Bond Elut SPE cartridges, inert flow paths (Ultra Inert liners, weldments, gold-plated inlet seals), Poroshell 120 UHPLC columns, Smart Key column ID, and certified reference materials.

Main Results and Discussion

All methods demonstrated excellent linearity, reproducibility, and low detection limits, typically below regulatory thresholds: VOCs at <0.1 ppb; semivolatiles and pesticides at ppt-to-ppb range; herbicides and PPCPs at ng/L; PFAS at pg-to-ng on-column; heavy metals at low ng/L or sub-ppt. Robustness was confirmed via spike/recovery tests (80–120% recoveries, RSDs <5%), certified reference materials, and cross-platform method transfers (e.g., Poroshell vs. Eclipse C18 UHPLC). Inert flow path solutions significantly improved active analyte responses, reducing adsorption and background interference.

Benefits and Practical Applications

These integrated solutions enable laboratories to:

• Meet stringent regulatory requirements for VOCs, pesticides, PFAS, and trace metals.
• Increase sample throughput through automated sample prep and fast separations.
• Achieve high confidence in data quality via inert flow paths and certified standards.
• Expand capabilities to non-target screening and unknown identification with high-resolution MS.

Future Trends and Possibilities

Emerging demands include wider monitoring of new contaminants (PPCPs, endocrine disruptors, nanoparticles), greater automation with online SPE and autosamplers, enhanced data processing via AI-driven software, and miniaturized, field-deployable instrumentation. Integration of high-resolution mass spectrometry with advanced informatics will facilitate non-target screening and real-time monitoring.

Conclusion

Agilent’s comprehensive portfolio addresses the full spectrum of water quality challenges, delivering sensitive, reliable, and efficient analytical workflows. By combining advanced sample preparation, inert hardware, diverse chromatographic and spectrometric platforms, and robust software, laboratories can confidently protect water resources and public health.

References

1. EU Directive 98/83/EC on the quality of water intended for human consumption.
2. US EPA Method 524.2: VOCs by purge and trap GC/MS.
3. US EPA Method 5035: Soil and water VOC sampling.
4. US EPA Method 200.7: Trace elements by ICP-OES.
5. US EPA Method 200.8: Trace elements by ICP-MS.
6. US EPA Method 245.1: Cold vapor AAS for mercury.
7. 5991-2108EN, 5991-0896EN, 5991-0017EN, 5991-1738EN, 5990-4864EN, 5991-4821EN, 5990-7932EN, 5994-0310EN, 5990-8765EN, 5990-8532EN, 5990-9735EN, 5990-6156EN.