Combining electroless ionisation mass spectrometry with solid-phase extraction for the direct analysis of beta-agonists in bovine urine

A novel method combining electroless ionisation mass spectrometry (ELI-MS) with solid-phase extraction (SPE) cartridges enables direct analysis of beta-agonist residues in bovine urine (SPE-ELI-MS). Using a syringe plunger and a battery-powered DIY syringe pump mounted on an XYZ-linear stage, rapid sample clean-up and precise positioning were achieved. Optimisation of spray solvent and nozzle placement improved performance, yielding high sensitivity, repeatability, linearity, and trueness with internal standard correction. This approach offers a simple, efficient solution for analysing organic residues in biological samples, with strong potential for future on-site applications.