3 research outputs found
High-Speed Tandem Mass Spectrometric in Situ Imaging by Nanospray Desorption Electrospray Ionization Mass Spectrometry
Nanospray desorption electrospray
ionization (nano-DESI) combined
with tandem mass spectrometry (MS/MS), high-resolution mass analysis
of the fragment ions (<i>m</i>/Δ<i>m</i> = 17 500 at <i>m</i>/<i>z</i> 200), and
rapid spectral acquisition enabled simultaneous imaging and identification
of a large number of metabolites and lipids from 92 selected <i>m</i>/<i>z</i> windows (±1 Da) with a spatial
resolution of better than 150 μm. Mouse uterine sections of
implantation sites on day 6 of pregnancy were analyzed in the ambient
environment without any sample pretreatment. MS/MS imaging was performed
by scanning the sample under the nano-DESI probe at 10 μm/s,
while higher-energy collision-induced dissociation (HCD) spectra were
acquired for a targeted inclusion list of 92 <i>m</i>/<i>z</i> values at a rate of ∼6.3 spectra/s. Molecular ions
and their corresponding fragments, separated by high-resolution mass
analysis, were assigned on the basis of accurate mass measurement.
Using this approach, we were able to identify and image both abundant
and low-abundance isobaric and isomeric species within each <i>m</i>/<i>z</i> window. MS/MS analysis enabled efficient
separation and identification of isomeric and isobaric phospholipids
that are difficult to separate in full-scan mode. Furthermore, we
identified several metabolites associated with early pregnancy and
obtained the first 2D images of these molecules