poster

Mass Spectrometry-Based Imaging Approaches to Spatial Localisation of Drugs in Tissue

Aim

To compare two approaches to imaging mass spectrometry for localisation of a drug,AZ-1, in rodent tissue samples. Important experimental considerations such as spatial resolution, time of acquisition and fit-forpurpose assessment were evaluated.

Methods

Matrix-assisted laser desorption/ionisation (MALDI) and liquid extraction surface analysis(LESA), coupled to a Waters Synapt G2 HDMS travelling wave ion mobility mass spectrometer.

Results

AZ-1 was successfully identified in dosed tissue slices by means of LESA-MS/MS and MALDIMS/MS experiments. Extra selectivity of an MS/MS experiment was required to identify the drug compound, due to the complexion mixture present in tissue sections.

Conclusions

Whilst both techniques can be used to analyse tissue sections, method choice will ultimately depend on the compound of interest within the tissue and spatial resolution required for the experiment.

More recently, an electrospray-based technique for imaging has been described, termed liquid extraction surface analysis  (LESA),  which  uses  a  chip-based  robotic  nanoelectrospray  platform  (TriVersa  NanoMate,  Advion) 3 .    This technique brings an extraction solvent into contact with the surface of a sample (e.g. tissue section) in a pre-defined position held by the NanoMate. Analyte compounds are then extracted from the surface and the solvent is sprayed through an ESI chip into the mass spectrometer.