The ESI source consists of a very fine needle and a series of skimmers. A sample solution is sprayed into the source chamber to form droplets. The droplets carry charge when the exit the capillary and as the solvent vaporizes the droplets disappear leaving highly charged analyte molecules. Electrospray ionization is the method of choice for proteins, oligonucleotides and metal complexes. Suitable for analyzing large bio- or synthetic polymers.
Sensitivity depends strongly upon the anlyte.
The ion sourceis similar to the ESI ion source. In addition to the electrohydrodynamic spraying process, a plasma is created by a corona-discharge needle at the end of the metal capillary. In this plasma proton transfer reactions and to a small amount fragmentation can occur. APCI characteristics in summary Provides molecular weight information. Sensitivity depends strongly upon the anlyte.