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.
Quantification is almost impossible without internal standards.
Monomeric or covalently-bound dimeric constitutes show no differences. Many important compounds of environmental or biological interest can produce negative ions under the right conditions. Negative ions can be produced by a number of processes. The electron energy is very low, and the specific energy required for electron capture depends on the molecular structure of the analyte. There is also a greater selectivity for certain environmentally or biologically important compounds.