Elevated pressure MALDI

An elevated pressure of typically a few millibars of inert gases such as He, Ar, or N2 in the ion source, can cool the ions and thereby increase their stability. If the MALDI ions coUide with these thermal gas molecules, some of their vibrational energy will be removed via a process known as collisional cooling. ... 

On-hne high-performance TLC (HPTLC) MALDI-FT-MS at elevated pressures was described in the direct analysis of gangliosides from TLC plates using soHd matrices [176]. Gangliosides are glycosphingolipids that contain one or more siahc... 

Figure 6.12. The first exploration of MALDI at elevated pressure showed reduced fragmentation of myoglobin and increased matrix adduction. (Reproduced from Ref. 121, with permission.)...

Figure 11.17. Schematic representations of external MALDI-FTMS systems. (A) vacuum MALDI-FTMS system where ions are generated in the external source and transferred to the analyzer cell via an RF-only multipole ion guide. (B) IP-MALDI-FTMS system. Argon is introduced in a short burst via a pulsed valve to briefly elevate the pressure within the source region. Ions are first stored in the source hexapole and undergo collisional cooling before transfer to the analyzer cell via an RF-only ion guide.

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