electrospray ionization

Electrospray ionization (ESI) is a technique used in mass spectrometry to ionize molecules. It is particularly useful for analyzing large, polar molecules like proteins and peptides, which are difficult to ionize using other methods. In ESI, a solution containing the sample is passed through a charged needle, creating a fine spray of charged droplets. As the solvent evaporates, the charge on the droplets increases, eventually leading to the ejection of gas-phase ions from the droplets. These ions are then analyzed by the mass spectrometer based on their mass-to-charge ratio. This method is valuable because it typically produces ions with minimal fragmentation, preserving the structure of the original molecule.123