Analysis of Pharmaceuticals and Pesticides in Bottled, Tap, and Surface Water Using ACQUITY UPLC Systems with 2D-LC Technology

Significance of the Topic

Monitoring trace levels of pharmaceuticals and pesticides in bottled, tap, and surface water is critical due to the growing number of regulated and emerging contaminants. Regulatory agencies demand detection at part-per-trillion levels to protect human health and ecosystems. Advanced hyphenated chromatography–mass spectrometry platforms with automated workflows can meet these stringent requirements while reducing time and resource consumption.

Objectives and Study Overview

This work demonstrates a streamlined micro-extraction protocol coupled with ACQUITY UPLC systems using two-dimensional LC technology and a Xevo TQD triple-quadrupole MS for simultaneous analysis of 20 pharmaceuticals and 18 pesticides. The study aimed to optimize trapping and elution conditions, maximize enrichment factors, evaluate recoveries, and establish low detection limits across bottled, tap, and surface water matrices.

Methodology and Instrumentation

• Sample Preparation: Micro-SPE using tandem 3 cc Oasis MAX/MCX cartridges and 15 mL water samples.
• At-Column Dilution: Direct loading of aqueous and organic extracts in a 2D-LC configuration, eliminating evaporation and reconstitution steps.
• Chromatographic Screening: Automated evaluation of 36 trap/elute conditions combining Oasis HLB, XBridge C18/C8 trap chemistries and BEH C18, HSS T3 separation columns under varying pH and solvent gradients.
• Detection: Xevo TQD in positive ESI mode with optimized MRM transitions for quantification and confirmation.

Main Results and Discussion

• Automated method development identified an optimal configuration (Method 28) that delivered well-resolved, Gaussian peaks and negligible breakthrough for all target analytes.
• Micro-extraction achieved a 15:1 concentration factor, complemented by up to 200:1 enrichment via at-column dilution, yielding an overall enrichment of 2000:1.
• Complete extraction protocol (loading, washing, elution) was performed in under 15 minutes; chromatographic separation required 10 minutes per run.
• Limits of detection of 1 ppt were achieved for the majority of analytes, with calibration curves linear from 1 to 100 ppt (r² > 0.99).
• Recoveries in bottled, tap, and surface water ranged from 80% to 118% (n = 6) for key pesticides and pharmaceuticals using targeted SPE fractions (reversed-phase and ion-exchange eluates).
• Fractionation studies highlighted complementary retention mechanisms: neutral and basic compounds eluted from reversed-phase traps, whereas charged analytes were captured and released by ion-exchange sorbents.

Benefits and Practical Applications

• High-throughput capability: Combined sample preparation and UPLC–MS analysis in under 25 minutes per sample.
• Exceptional sensitivity: Low ppt detection limits without lengthy solvent evaporation or exchange.
• Flexible workflow: Automated screening enables rapid optimization for chemically diverse analyte panels.
• Robust performance: Consistent recoveries across multiple water types support routine environmental and QA/QC monitoring.

Future Trends and Opportunities

• Coupling with high-resolution MS for non-targeted screening of emerging contaminants.
• Development of field-deployable SPE–LC systems for on-site water analysis.
• Extension to additional compound classes, such as PFAS and polar metabolites.
• Integration of machine learning for automated method development across multidimensional platforms.

Conclusion

The combination of micro-SPE extraction, ACQUITY UPLC two-dimensional LC, and Xevo TQD MS offers a comprehensive, rapid, and sensitive workflow for monitoring pharmaceuticals and pesticides in water. The optimized protocol delivers high enrichment, reliable recoveries, and low ppt detection limits across multiple matrices, addressing current regulatory and environmental challenges.

Used Instrumentation

• ACQUITY UPLC 2D-LC system with at-column dilution.
• Oasis MAX and MCX SPE cartridges (3 cc, 60 mg).
• BEH C18 and HSS T3 UPLC columns (2.1 × 50 mm).
• Xevo TQD triple-quadrupole mass spectrometer in positive ESI mode.

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