Mass spectrometers are devices for measuring the mass-to-charge ratio of molecules and ions. They use many different measurement principles and are used in various areas of science. Our guest Alexander Makarov works as a Director Global Research for Thermo Fisher's Life Sciences Division and has invented the Orbitrap principle used widely in modern mass spectrometers. We talk about mass spectrometry in general, the different measurement principles, engineering challenges, the invention of the Orbitrap, use cases for mass spectrometers and the different machines sold by Thermo Fisher.