CHEMICAL-IONIZATION

In chemical ionization, the analyte of interest is ionized by gas-phas e ion/molecule reactions between suitable reagent ions and gaseous ana lyte molecules. The major ionic reagents which have been developed inc lude gaseous Bronsted acids and bases and charge exchange reagents; in addition, reagent gases which promote electron attachment have seen e xtensive use. The present paper reviews the major features and uses of these reagent systems as well as recent developments in the instrumen tation for chemical ionization.