Atmospheric Pressure Chemical Ionization Source (APCI)
Atmospheric pressure chemical ionization (APCI) is a popular complementary soft ionization technique to electrospray. It is commonly used to analyze small polar and nonpolar compounds that are ionized poorly by electrospray but do well in chemical ionization, which generates singly charged ions at higher temperatures.
The Agilent APCI source is sensitive yet extremely robust, thanks to an orthogonal spray geometry and counterflow drying gas. Like the ESI source, it can generate both positive and negative ions, and ion polarity can be switched on a spectrum-to-spectrum basis.
Features
Complementary to electrospray ionization
Suitable for a wide range of compounds, including less polar and nonpolar molecules
Generates primarily singly charged ions and operates at higher temperatures
Performance scales favorably for larger columns and higher LC flow rates as the response increases with the total mass flow