Mass Spectrometry Applications for Environmental Analysis

Significance of the Topic

Water resources worldwide are increasingly contaminated by trace levels of pesticides, pharmaceuticals, personal care products, and their transformation products. These emerging organic contaminants (EOCs) pose potential risks to ecosystems and human health. Fast, robust, and sensitive analytical approaches are needed to monitor a wide variety of compounds across wastewater, surface water, and drinking water.

Objectives and Overview

This summary reviews innovative analytical workflows that combine direct or on-line sample preparation with high-resolution, accurate-mass liquid chromatography-mass spectrometry (LC-MS). Methods employ either direct analysis in real time (DART) with Orbitrap MS or large-volume injection SPE HPLC coupled to Orbitrap or triple quadrupole instruments. Additional techniques include full-scan and data-dependent MS/MS for both targeted quantitation and non-targeted screening.

Methodology and Instrumentation

• Direct DART-Orbitrap MS: Desorption ionization of water samples on mesh strips at 300 °C for rapid pesticide screening without HPLC.
• On-line SPE HPLC-Orbitrap MS: Large volumes (1–20 mL) injected onto trapping (C18/Hypercarb) and analytical columns (Hypersil GOLD) with gradient elution for pesticides, herbicides, or pharmaceuticals.
• U-HPLC-Orbitrap MS: High-throughput direct injections of drinking water for antibiotic analysis using Accela/LT pumps and Exactive/Exactive Plus instruments in full-scan/AIF modes.
• Triple quadrupole LC-MS/MS: Water samples injected onto loading columns and back-flushed onto analytical columns, followed by SRM or Timed-SRM acquisition on TSQ Quantum platforms.
• Data processing: Spectral confirmation, isotopic pattern matching, and retrospective screening using TraceFinder, ExactFinder, SIEVE, and spectral libraries.

Main Results and Discussion

LOQs in the low nanogram-per-liter or nanogram-per-milliliter range (often < 1 ng/L or < 1 ng/mL) were achieved across multiple compound classes. Recoveries typically ranged from 70 % to 110 % with RSDs < 15 %. Concentrations of dozens to hundreds of analytes were measured in real samples, demonstrating high throughput. Timed-SRM methods enabled monitoring of > 300 pesticides in a single run. Full-scan HRAM data allowed identification of non-target compounds and retrospective analysis of added analytes.

Benefits and Practical Applications

• Eliminates time-consuming offline sample preparation, reducing sample volume requirements.
• High-throughput screening and quantitation of hundreds of analytes in a single LC run.
• Enhanced selectivity and sensitivity through high-resolution mass analyzers and Timed-SRM scheduling.
• Integrated targeted and non-targeted workflows with retrospective data mining.
• Robust matrix tolerance and minimized interferences, suitable for complex water matrices.

Future Trends and Applications

Integrated high-resolution MS platforms will continue to advance non-targeted screening capabilities. Automated large-volume injection and direct-analysis techniques will expand monitoring of emerging contaminants. Combined with advanced data-analysis tools and spectral libraries, these workflows will support real-time water quality surveillance and regulatory compliance.

Conclusion

Modern LC-MS workflows employing direct-analysis or on-line SPE combined with high-resolution Orbitrap or triple quadrupole MS deliver sensitive, selective, and high-throughput detection of a broad range of pesticides, pharmaceuticals, and personal care products in water. These approaches streamline sample preparation, reduce analysis time, and enable comprehensive targeted and non-targeted monitoring.

References

1. Kümmerer, K. “Pharmaceutically Active Compounds in the Environment” (2004).
2. Richardson, S.D.; Ternes, T.A. “Water Analysis: Emerging Contaminants and Current Issues” (2018).
3. Martins, A.; et al. “Rapid Analysis of Pesticides by DART-Orbitrap MS” (2014).
4. Beck, J.R.; Yang, H. “On-line SPE LC-Orbitrap MS for Pesticides” (2016).
5. Liu, X.; et al. “High-resolution LC-MS for Antibiotics in Drinking Water” (2016).
6. Rafferty, J.L.; Siepmann, J.I. “Divert Valve Technique for Pesticides in Acetonitrile” (2011).
7. Beck, J.; Chang, J. “EQuan LC-MS/MS for Pesticides in Water” (2010).
8. Gross, J. “Mass Spectrometry” 2nd Ed. (2011).
9. Boix, D.; et al. “DART Pesticide Analysis” (2013).
10. Landesman, D. “Environmental Analysis by LC-MS” (2015).
11. Matuszewski, B.K.; et al. “Matrix Effects in Quantitative LC/MS” (2003).
12. EURACHEM “Guidance on Analytical Quality Control in Water Analysis” (2014).