Chemical Sciences: A Manual for CSIR-UGC National Eligibility Test for Lectureship and JRF/Ambient ionization

Ambient ionization is a form of ionization in which ions are formed outside the mass spectrometer without sample preparation or separation.

Direct analysis in real time
Direct analysis in real time (DART) is an atmospheric pressure ion source that operates by exposing the sample to a gas stream (typically helium or nitrogen) that contains long-lived electronically or excited neutral atoms, vibronically excited molecules (or "metastables"). Excited states are formed in a glow discharge in a chamber through which the gas flows..

Desorption electrospray ionization
Desorption electrospray ionization (DESI) uses an electrospray source to create charged droplets that are directed at a solid sample. The charged droplets pick up the sample through interaction with the surface and then form highly charged ions that can be sampled into a mass spectrometer.

Desorption atmospheric pressure photoionization
Desorption atmospheric pressure photoionization (DAPPI) enables direct analysis of samples deposited on surfaces by means of a jet of hot solvent vapour and ultraviolet light. The hot jet thermally desorbs the sample from a surface and the vaporized sample is ionized by a vacuum ultraviolet light and consequently sampled into a mass spectrometer.

Laser assisted
Electrospray-assisted laser desorption/ionization (ELDI) relies on a laser to the desorption of material into the electrospray plume. With matrix-assisted laser desorption electrospray ionization (MALDESI), a nitrogen laser is used to desorb material into the electrospray. MALDESI has been used with MALDI matrix materials. Laser ablation electrospray ionization (LAESI) uses an infrared laser for ablation of the sample material. The term laser spray ionization has been used to describe transmission mode laser ablation coupled with electrospray ionization.