Increased Throughput in the Determination of PPCPs in Water Using Optimized MS Cycle Times in a High Sensitivity UHPLC-Triple Quadrupole System

Importance of the Topic

Pharmaceuticals and personal care products (PPCPs) are emerging contaminants in surface waters that can harm aquatic life at trace levels. Rapid, sensitive, and high-throughput analytical methods are essential to monitor these compounds effectively without extensive sample preparation.

Objectives and Study Overview

This study evaluates optimized software and firmware modifications in a UHPLC-triple quadrupole MS system to reduce inter-MRM delay times, enabling direct injection of water samples and high-throughput analysis of 32 PPCPs down to 0.5 ng/L.

Methodology and Instrumentation

Sample preparation consisted of simple filtration and direct injection (40 μL) without solid-phase extraction. An Agilent 1290 Infinity II UHPLC with a ZORBAX Eclipse Plus RRHD C18 column (2.1×50 mm, 60 °C) was coupled to an Agilent 6495 triple quadrupole MS with Jet Stream ionization. Mobile phases were water and acetonitrile (0.03 % formic acid), operated at 0.5 mL/min with polarity-switching MRM. Inter-MRM delays were optimized to allow dwell times of 0.5 ms.

Results and Discussion

Direct injection and optimized inter-MRM delays yielded the following outcomes:

• Analysis of 32 PPCPs in a 6 min UHPLC run, achieving limits of quantitation as low as 0.5 ng/L.
• Dwell time comparison showed <12 % signal loss at 0.5 ms versus 5 ms settings.
• Calibration curves for diclofenac and venlafaxine displayed R² > 0.997 over 0.5–1000 ng/L, with RSD < 10 % and accuracy between 85–112 %.
• Reproducible responses (RSD < 10 %) at sub-ng/L levels for atrazine and diltiazem.
• Screening of real surface water samples identified differing PPCP profiles, including bupropion and lamotrigine at ng/L concentrations.

Benefits and Practical Applications

The method eliminates time-consuming SPE, delivering high throughput and sensitivity in a single polarity-switching run. It is well-suited for routine environmental monitoring and QA/QC of water samples.

Future Trends and Potential Applications

Future developments may include expanding analyte panels, integrating online sampling interfaces, and real-time field deployable systems to support continuous water quality surveillance.

Conclusion

Optimized inter-MRM delay times in a high-sensitivity UHPLC-triple quadrupole system enable sub-ms dwell times, direct injection of untreated water, and swift analysis of multiple PPCPs with excellent accuracy and precision.

Reference

Agilent Technologies. Application Note 5991-7299EN, December 2016.