Quick screening of priority β-agonists in urine using automated TurboFlow™-LC/Exactive mass spectrometry

Abstract

This paper describes a method for the determination of priority β-agonists in urine based on a fully automated sample preparation procedure using an online TurboFlow™ chromatography clean-up step and determination with Orbitrap™ mass analyser technology. The principle of the method was the enrichment of the β-agonists after enzymatic hydrolysis overnight on a small column packed with a special stationary phase (TurboFlow™) while flushing away sample matrix and interfering compounds. Thereafter, the analytes were transferred onto an analytical column and detected by liquid chromatography/high-resolution mass spectrometry in full-scan mode at a resolution of R = 50,000 FWHM (full width at half maximum) and in higher energy collisional dissociation (HCD) scan mode at a resolving power of 10,000 FWHM. The optimisation of each step of the method, such as selection of the TurboFlow™ and analytical column as well as sample loading and elution parameters were performed using a standard solution containing salbutamol, clenbuterol and mabuterol at a concentration of 100 µg l⁻¹. The developed automated sample preparation significantly improved the throughput and efficiency of the previously used screening method and it resulted in a considerable reduction in analysis time. Validation experiments including 24 β-agonists in urine gave decision limits (CCα) between 0.05 and 0.35 µg l⁻¹. The repeatability of analyses for urine samples spiked at 0.5 µg l⁻¹ was within the range of 5–26% and recoveries for all compounds were within 89–107%.

Keywords:

• beta-agonists
• urine
• TurboFlow™
• Orbitrap™
• LC/MS

Acknowledgements

The authors would like to acknowledge Dr Francois Espourteille, Thermo Fisher Scientific, Franklin, MA, USA, for help with the initial TurboFlow™ method optimisation and column selection