National Physical Laboratory

DESI Measurement Services

Desorption Electrospray Ionisation (DESI)Close-up of the LGC/NPL DESI (Image courtesy of LGC) 

Desorption Electrospray Ionisation (DESI) is a highly sensitive surface mass spectrometry technique capable of analysing a wide range of surfaces under ambient conditions.

DESI is an ambient mass spectrometry development from the Cooks group at Purdue [Science, 306, 471 (2004)]. It uses an electrospray source of aqueous spray droplets to desorb ions from a sample surface and these ions are analysed in a standard electrospray mass spectrometer. The technique has the advantages of directly analysing a surface coupled with MS/MS capability under ambient conditions. It has been shown to be possible to analyses a wide range of analytes: amino acids; peptides; proteins; drug molecules; explosives and polymers, directly from everyday surfaces such as fabrics, plants, tissue and blood. A recent review paper from NPL describes the use of ambient mass spectrometries for forensics. Present DESI capability at NPL allows better than 15% repeatability, lateral imaging of 150 μm resolution and extremely high mass resolution of < 100,000 u using a Thermo Velos LTQ Orbitrap MS.

We are also keen to develop other ambient mass spectrometry techniques and presently have AP-MALDI, plasma desorption ionisation (PADI) MS (M McCoustra et al, Anal. Chem. 2007; 79, 1447) and extractive electrospray ionisation (EESI) MS (R Zenobi et al, Anal. Chem. 2007; 79, 6094) available at NPL.

Download poster detailing DESI applications entitled 'Applications of DESI for direct ambient surface analysis' (Adobe pdf file PDF 521 KB)


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Last Updated: 6 Mar 2012
Created: 29 May 2009


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