Atmospheric Pressure Chemical Ionization (APCI) Technique

Atmospheric pressure chemical ionization relies upon the formation of a plasma or ions comprised, mainly, from the HPLC mobile phase components. As the solvent-evaporation and ion-formation processes are separated in APCI, this allows the use of low-polarity solvents that are unfavorable for ESI ion formation. APCI is employed for analytes which are less polar and which have lower molecular weight than those suitable for electrospray. This module explains the important parameters when using APCI and offers practical tips on source parameter optimization.

Topics include:

• Eluent additives in APCI
• Signal suppression by additives in APCI
• Alternative APCI charging mechanism
• APCI source parameter optimization
• Comparison of ESI/APCI ionization techniques