Professor William Alexander Donald (known as Alex to colleagues) is a researcher in bioanalytical chemistry and mass spectrometry at the University of New South Wales. His team focuses on developing methods and instrumentation to advance the fundamentals and applications of mass spectrometry. His research includes multiplexed screening methods for identifying protein-ligand and protein-protein interactions using native mass spectrometry, as well as determining binding affinities for multiple ligands simultaneously. His group has also integrated interpretable machine learning into mass spectrometry-based omics workflows and developed an ambient pressure ion funnel that enhances signal intensity for atmospheric pressure ion sources by up to 17-fold. Alex has received several awards, including the Bowie Medal from the Australian and New Zealand Society for Mass Spectrometry and the Peter W. Alexander Medal from the Royal Australian Chemical Institute.