Accurately Identify Emerging Environmental Chemical Contaminants - Application Compendium

Význam tématu

Water treatment plants receive a wide variety of organic chemicals from domestic, agricultural and industrial sources. Many of those compounds and their transformation products are not regulated or monitored, yet pose potential ecological and health risks. Targeted methods cover only a small fraction of the >85 million registered chemicals and the ~7 500 substances listed in regulatory candidate lists. High-resolution accurate-mass LC/Q-TOF mass spectrometry combined with comprehensive compound databases and libraries provides an efficient workflow for both known and suspected contaminants and for discovery of unknowns in WWTP effluents. Monitoring changes in a broad set of compounds during treatment steps informs process efficiency and safety of water reuse.

Cíle a přehled studie

• Develop an accurate-mass MS/MS compound database and library (Water Screening PCDL) covering ∼1 400 pesticides, pharmaceuticals, personal care products and their degradates.
• Establish targeted and suspect screening workflows using All Ions MS/MS and auto MS/MS acquisition modes on an Agilent 6550 iFunnel Q-TOF LC/MS.
• Apply methods to 14-day composite effluent samples from four central European WWTPs over a 3½-month period, covering the main pesticide application season.
• Identify and (semi-)quantify >390 target compounds and perform suspect screening on the full PCDL.

Použitá instrumentace

• Agilent 1290 Infinity II UHPLC with 100 µL large-volume injection.
• Agilent 6550 iFunnel Q-TOF MS with Dual Spray Jet Stream ESI.
• Agilent All Ions MS/MS acquisition at 0, 20, 40 V; and targeted auto MS/MS at 5 scans/s.
• Workflows executed in MassHunter Acquisition, Qualitative Analysis and PCDL Manager.

Použitá metodika

• 14-day composite influent and effluent samples from four WWTPs (two agricultural, two urban) collected March–June.
• Filtration, large-volume injection (100 µL), UHPLC separation on ZORBAX RRHD SB-Aq (2.1×150 mm, 1.8 µm).
• All Ions MS/MS screening with coelution confirmation of precursor and MS/MS fragments.
• Auto MS/MS inclusion list for compounds lacking library spectra.
• Recursive feature extraction and blank subtraction for suspect screening.
• Identification based on accurate mass (<5 ppm), isotope pattern, retention time (±1 min) and MS/MS match.

Hlavní výsledky a diskuse

• Water Screening PCDL built from >1 000 compounds with curated MS/MS spectra for [M+H]+, [M–H]– and adducts, retention times added for 390 compounds.
• Targeted screening: 315 compounds detected in positive mode, 75 in negative; >60 % quantified at ≤10 ng/L, 35 % at 10–100 ng/L.
• Common pharmaceuticals in effluents: X-ray contrast media iomeprol (≤7 µg/L) and iopromide (≤2 µg/L), beta blockers atenolol (≤1.7 µg/L), metoprolol (≤0.47 µg/L), tramadol, carbamazepine, ibuprofen, naproxen, sulfamethoxazole, metabolites of carbamazepine and sulfamethoxazole.
• Fewer pharmaceuticals but higher concentrations in smaller agricultural WWTPs.
• 46 pesticides detected, e.g. DEET (14–770 ng/L), metolachlor (≤1.1 µg/L), isoproturon (≤450 ng/L). Agriculturally dominated plants showed seasonal increases (e.g. azoxystrobin).
• All Ions MS/MS enabled rapid confirmation of library compounds; auto MS/MS captured spectra for suspects lacking library entries.

Přínosy a praktické využití metody

• Comprehensive screening of regulated and emerging contaminants in WWTP effluents.
• Archival full-scan Q-TOF data enable future re-interrogation for new suspects.
• Efficient workflows for high-confidence identification and semi-quantification at low ng/L levels.
• Coelution-based fragment confirmation increases specificity without authentic standards.
• Large-volume injection UHPLC/Q-TOF supports direct injection analysis of water samples.

Budoucí trendy a možnosti využití

• Expand databases with more transformation and emerging compounds, including PFAS, micropollutants.
• Integrate suspect screening with in-silico fragmentation tools for non-target identification.
• Apply machine-learning for automated feature prioritization and contaminant profiling.
• Combine high-resolution MS data with effect-directed analysis to link compound occurrence with toxicity.
• Implement real-time monitoring platforms for drinking water reuse facilities.

Závěr

High-resolution accurate-mass Q-TOF LC/MS combined with comprehensive MS/MS databases and robust data analysis software provides an integrated workflow for simultaneous targeted quantification, suspect screening and discovery of unknowns in complex WWTP effluents. The method efficiently identified hundreds of regulated and emerging contaminants and their transformation products at trace levels, supporting surveillance and risk assessment for potable reuse and environmental protection.

Reference

1. European Union. Directive 2000/60/EC (Water Framework Directive).
2. European Union. Directive 2013/39/EU (Priority Substances Directive).
3. US EPA Method 1694. Pharmaceuticals and Personal Care Products in Water, Soil, Sediment, and Biosolids by HPLC/MS/MS.
4. US EPA Contaminant Candidate List (CCL4), 2015.
5. Jensen, E. et al. Environ. Int., 2015, 84, 117–125.
6. Verlicchi, P. et al. Sci. Total Environ., 2010, 408, 352–370.
7. National Research Council. Water Reuse: Potential for Expanding the Nation’s Water Supply, 2012.
8. Snyder, S.A. et al. Environ. Eng. Sci., 2007, 24(7), 755–772.
9. Hufnagel, L. et al. Anal. Chem., 2017, 89(15), 8145–8154.