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Desorption electrospray ionization (DESI) is an ambient ionization technique that can be coupled to mass spectrometry (MS) for chemical analysis of samples at atmospheric conditions. Coupled ionization sources-MS systems are popular in chemical analysis because the individual capabilities of various sources combined with different MS systems ...
Extractive electrospray ionization is a spray-type, ambient ionization method that uses two merged sprays, one of which is generated by electrospray. [ 49 ] Laser-based electrospray-based ambient ionization is a two-step process in which a pulsed laser is used to desorb or ablate material from a sample and the plume of material interacts with ...
One example is fast-atom bombardment ionization which can allow for liquid samples separated by the LC to flow into the ionization chamber and be ionized easily. [1] The most common ionization method coupled to LC is some form of spray ionization, which includes thermospray ionization and more commonly, electrospray (ESI) ionization.
DESI and DART are considered as pioneer techniques in the field of ambient ionization, [4] since they operate in the open laboratory environment and do not require sample pretreatment. [5] [6] In contrast to the liquid spray used by DESI, the ionizing gas from the DART ion source contains a dry stream containing excited state species.
Nanospray desorption electrospray ionization (nano-DESI) is an ambient pressure ionization technique used in mass spectrometry (MS) for chemical analysis of organic molecules. [1] In this technique, analytes are desorbed into a liquid bridge formed between two capillaries and the sampling surface. [ 2 ]
One example is electrospray laser desorption ionization (ELDI), which uses an ultraviolet laser to form ions by irradiating the sample directly, then interacting with the electrospray plume without using any matrices. [40] The infrared version of ELDI has been referred to as laser ablation electrospray ionization (LAESI). IR-MALDESI differs ...
The energy of the electron beam is typically 70 electronvolts and the ionization process typically produces extensive fragmentation of the chemical bonds of the molecule. Due to the high vacuum pressure in the ionization chamber, the mean free path of molecules are varying from 10 cm to 1 km and then the fragmentations are unimolecular processes.
Secondary electrospray ionization mechanism diagram. In the early days of SESI, two ionization mechanisms were under debate.: the droplet-vapor interaction model postulates that vapors are adsorbed in the electrospray ionization (ESI) droplets, and then reemitted as the droplet shrinks, just as regular liquid phase analytes are produced in electrospray ionization; on the other hand, the ion ...