Application of MALDI-MSI in
Supervisor: Prof. Hui-Fen Wu
Student: Hani Nasser Abdelhamid
M.Sc student at NSYSU, Taiwan (ROC)
Tutor at Assuit university, Egypt.
Discussion and Questions.
Mass spectrometry components
•Douglas A. Skoog, F James Holler, Stanley R. Crouch, Principles of Instrumental Analysis, six edition ,Thomson Higher
Education 10 Davis Drivt' Belmont,p564.
• Quadrupole analyzer.
• Ion trap (IT) instruments,
• time-of-flight (TOF),
• Orbitrap .
• Ion cyclotron resonance (ICR) mass
• ESI triple quadrupole (ESI-QQQ).
Matrix Assisted Laser Desorption
Beate Fuchs et.al. Progress in Lipid Research 2010.49 ,450–475
Alexandra P. Kafkaa et.al. International Journal of Pharmaceutics 2011,417 70– 82
MALDI TOF matrices should be:
1. embed and isolate analytes (e.g., by co-crystallization).
2. be soluble in analyte-compatible solvents.
4. absorb the laser wavelength.
5. initiate co-desorption of analyte upon laser irradiation
6. promote analyte ionization .
Both choice of matrix and sample preparation have been shown to influence the nature of
molecules that can be detected using MALDI TOF and the quality of the resulting data
• 50–60% of the constituents of cell membranes.
• 20–25% of the Brain dry weight .
• provide energy for the body( lysosomes ).
• Disorder of lipid distribution cause a lot of
Wolman Disease, and
Lysosomal acid lipase LAL deficiency .Cell death
• Presence of adduct ions [M+Na]+
• Contamination from solvent.
• Lateral diffusion(analyte delocalization) due to solvent.
Two solvent free techniques,
dry-coating and sublimation
The dry-coating technique
deposits finely ground matrix onto tissue slices
by the direct filtering of solid matrix particles
through a 20 μm stainless steel sieve.