Chemical ionization

Formation of a new ion in the gas phase by the reaction of a neutral species with an ion. The process may involve transfer of an electron, a proton or other charged species between the reactants.

Note 1: When a positive ion results from chemical ionization the term may be used without qualification. When a negative ion results the term negative ion chemical ionization should be used.

Note 2: this term is not synonymous with chemi-ionization.

Describes the process whereby new ionized species are formed when gaseous molecules interact with ions. The process may involve transfer of an electron, a proton or other charged species between the reactants. When a positive ion results from chemical ionization the term may be used without qualification. When a negative ion results the term negative ion chemical ionization should be used. Note that this term is not synonymous with chemi-ionization, nor with negative chemical ionization.

http://goldbook.iupac.org/C01026.html

This concerns the process whereby new ionization species are formed when gaseous molecules interact with ions. The process may involve transfer of an electron, proton or other charged species between the reactants. When a positive ion results from chemical ionization, the term may be used without qualification. When a negative ion is involved, the term negative ion chemical ionization should be used; note that negative ion formation by attachment of a free electron does not fall within this definition. Chemical ionization and chemi-ionization are two terms which should not be used interchangeably. See: electron attachment

See also: chemi-ionization

Source: PAC, 1991, 63, 1541 (Recommendations for nomenclature and symbolism for mass spectroscopy (including an appendix of terms used in vacuum technology). (Recommendations 1991)) on page 1547

Orange Book, p. 204

PAC, 1990, 62, 2167 (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2179

Method in which neutral molecules are ionized by ion-molecule reactions to generate a parent ion at a pressure of about 1 torr.