Analysis of Pharmaceuticals in Municipal Drinking Water by Gas Chromatography–Time-of-Flight Mass Spectrometry (GC-TOFMS)

Significance of the topic

This study addresses the growing concern of pharmaceutical residues entering municipal drinking water and the associated risks to public health and the environment. Conventional treatment facilities often fail to remove all drug metabolites, highlighting the need for advanced analytical methods to detect trace contaminants.

Objectives and overview

The goal of this work was to develop and demonstrate a non-target and target screening workflow using Gas Chromatography–Time-of-Flight Mass Spectrometry (GC-TOFMS) on the LECO Pegasus HT platform. Spiked tap water samples containing common over-the-counter and prescription drugs served to evaluate method performance.

Sample preparation and methodology

A tap water sample was fortified with ibuprofen, acetaminophen, sertraline, zolpidem, and lovastatin. The mixture was sonicated, filtered, and subjected to solid-phase microextraction using a 50/30 DVB-Carboxen-PDMS fiber. Thermal desorption at 270 °C was followed by GC separation on an Rtx-5 column (10 m × 0.18 mm × 0.18 µm) with a temperature gradient from 40 °C to 300 °C. The Pegasus HT TOFMS acquired full-range spectra (m/z 40–800) at 10 spectra/s under 70 eV electron ionization.

Used instrumentation

• Gerstel MPS2 autosampler with SPME option
• Agilent 6890 Gas Chromatograph
• LECO Pegasus HT Time-of-Flight Mass Spectrometer
• ChromaTOF software for instrument control and spectral deconvolution

Main results and discussion

All spiked analytes were detected with high confidence by automated peak finding and library matching. Mass spectral deconvolution resolved coeluting compounds by isolating unique ion patterns, producing “clean” spectra with similarity scores above 880. The method also identified additional matrix components, demonstrating broad coverage for non-target screening.

Benefits and practical applications

• High sensitivity across the full mass range supports trace-level detection
• Spectral deconvolution accelerates analysis of complex samples
• Non-target capability uncovers emerging contaminants
• Applicable to environmental monitoring and water quality compliance

Future trends and potential applications

Integration of high-resolution MS and advanced deconvolution algorithms, along with machine learning, will further enhance non-target screening. Expansion of this workflow to wastewater, surface water, and biota will support comprehensive environmental surveillance and risk assessment.

Conclusion

The Pegasus HT GC-TOFMS platform delivers robust and efficient detection of pharmaceutical residues in drinking water. Its combination of full-range acquisition, high sensitivity, and powerful spectral deconvolution makes it an indispensable tool for safeguarding water quality and tracking emerging contaminants.