Online SPE Analysis of Pharmaceutical Compounds in Environmental Waters

Significance of the Topic

Pharmaceutical residues in environmental waters pose growing concerns due to incomplete removal during treatment processes and potential ecological and human health impacts even at trace levels.

Objectives and Study Overview

• Develop and evaluate an automated online SPE-LC/MS/MS workflow for simultaneous analysis of 20 pharmaceutical compounds in drinking water, surface water, and wastewater.
• Assess method performance in terms of linearity, limits of detection, precision, recovery, and carryover.
• Demonstrate robustness of PLRP-S trap cartridges and high-throughput capability.

Methodology and Instrumentation

Online SPE was performed using an Agilent 1200 Infinity Series Online SPE Solution with a PLRP-S trap cartridge, integrated with an Agilent 1290 Infinity Flexible Cube and Agilent 6400 Series Triple Quadrupole LC/MS employing Jet Stream ESI. Key chromatographic conditions included a ZORBAX SB-Aq column (2.1 × 100 mm, 3.5 μm) at 35 °C, a 0.1 % acetic acid/ammonium acetate aqueous phase, acetonitrile as the organic phase, and a 16-minute gradient. Samples (900 μL) were spiked, centrifuged, and injected at 5 °C.

• Agilent 1290 Infinity Flexible Cube with Online SPE Starter Kit
• Agilent 1260 Infinity Binary Pump and Autosampler
• Agilent 1260 Infinity Thermostatted Column Compartment
• Agilent 6400 Series Triple Quadrupole LC/MS with Jet Stream ESI
• Agilent MassHunter suite for data acquisition and processing

Key Results and Discussion

• Linearity: Most compounds showed R² ≥ 0.99 over 0.001–1.0 μg/L; LODs ~0.001 μg/L (some up to 0.005 μg/L).
• Precision: Area and retention time RSDs generally <5 % and <0.2 %, respectively; cartridges withstood >200 cycles with <10 % variability.
• Recovery: 70–120 % for the majority of analytes in drinking and surface water; matrix suppression effects observed in complex wastewater samples, suggesting isotope-labelled standards or matrix-matched calibration.
• Carryover: Negligible (<0.3 %) for all compounds except bisoprolol.

Benefits and Practical Applications

This online SPE approach reduces solvent use and waste, shortens sample preparation, and supports high-throughput quantitation of pharmaceuticals at trace levels. It is well suited for environmental monitoring, regulatory compliance, and quality control laboratories.

Future Trends and Opportunities

• Integration of isotopically labelled internal standards for matrix effect compensation.
• Expansion to emerging contaminants, including polar metabolites and PFAS compounds.
• Adoption of high-resolution mass spectrometry for non-target screening.
• Implementation of advanced automation and AI-driven data analysis for rapid surveillance.

Conclusion

The Agilent 1200 Infinity Series Online SPE Solution coupled with triple quadrupole LC/MS provides a robust, sensitive, and efficient workflow for monitoring pharmaceutical residues in various water matrices, enabling reliable environmental surveillance.

References

• Idder S. et al. Anal. Chim. Acta 2013;805:107-115.
• Heberer T.; Stan H.J. Int. J. Environ. Anal. Chem. 1997;67:113-123.
• Trenholm R.A. et al. Talanta 2009;79:1425-1432.
• Schuhn B. et al. Agilent Application Note 5991-2405EN, 2013.
• Togola A. et al. Anal. Bioanal. Chem. 2014;406:1181-1191.
• European Commission SANCO/12571/2013. Guidance on analytical quality control and validation procedures.