Giuseppe Paglia, Post Doctoral Researcher at CSB:
 

Ambient Desorption Ionization Mass Spectrometry: Analytical and Biomedical Applications

 
Friday March 12th at 15:00
Askja Room 131
 
Ambient desorption ionization mass spectrometry methods are characterized by operating in the open air, and with the ability to probe the surface of samples of any size and shape. These techniques typically require little or no sample preparation, offer a much simplified work flow and deliver unprecedented ease of use to MS analyses.
 
Desorption electrospray ionization (DESI), developed by Cooks et al. 1 , is the principal method in this new family of ionization methods and it easily ionizes a wide range of analytes.   Nevertheless the ionization of compounds with lower proton affinity requires the use of other ambient desorption methods. For the ionization of such compounds reactive-DESI and atmospheric pressure thermal desorption chemical ionization (APTDCI) provide better performances.  DESI-MS has been used for the direct analysis of porcine brain lipids providing molecular imaging of separate spots on high-performance thin-layer chromatography (HPTLC) plates.  Polar lipids spots were imaged in the negative ion mode and their identity confirmed by tandem MS.   The possibility of mapping the distribution of non-polar lipids has been briefly explored by reactive DESI using betaine aldehyde to derivatize cholesterol so generating the quaternary which can be observed directly from the plate.  Moreover APTDCI-MS and DESI-MS methods have been employed for the ionization of sterols, aminoacids and acylcarnitines which are used as diagnostic marker in some metabolic inherited diseases.
 
The ability of ambient desorption ionization techniques to interrogate compounds directly from dried blood/plasma spot has been used to develop fast methods for the screening of some inborn errors of the metabolism.
 
1)      Cooks RG, Ouyang Z, Takats Z, Wiseman JM. Science . 2006, 17;311(5767):1566-70.