Mass Spectrometry explained – how it works

Overview of mass spectrometry as an analytical technique that measures mass-to-charge ratios. Explanation of its primary use in measuring and identifying molecules within samples, particularly in protein analysis and proteomics research.

Complex samples are separated by liquid chromatography before being inserted into the mass analyzer. This prepares the sample for the subsequent ionization steps.

Transfer molecules into the gas phase using electrospray ionization (ESI), where a capillary with applied electric field creates charged gas-phase ions through electrostatic repulsion and aerosol formation.

Ions pass through slits and are accelerated in a focused ion beam using an electric field with known voltage, preparing them for separation in the analyzer.

Ions travel through the flight tube at different speeds based on their mass-to-charge ratio. Lighter ions and more highly charged ions travel faster than heavier or singly-charged ions with the same mass.

Ions reach the detector and arrival times are measured. Since the distance traveled is known, the mass-to-charge ratio can be calculated for each ion.

Quantify ions and display results as a mass spectrum chart with mass-to-charge ratios on the x-axis and relative intensity on the y-axis. Use databases and isotope patterns to identify sample molecules.

Recap the complete mass spectrometry process from sample ionization through acceleration and analysis to final identification using mass spectrum data and reference databases.