APCI source

An APCI source uses a corona discharge to ionize neutral molecules from a vaporized sample at atmospheric pressure, facilitating their analysis in mass spectrometry (MS). It is a soft ionization technique particularly effective for non-polar to moderately polar, thermally stable compounds that may not ionize well with other methods like electrospray ionization (ESI). APCI is commonly coupled with chromatography (HPLC or GC) for qualitative and quantitative analyses of compounds like pharmaceuticals, pesticides, and petrochemicals.