Question

1. What information does MALDI imaging mass spectrometry provide

2. How to make positive and negative ions in mass spectrometry

3. What are major limitations of mass spectrometry for protein biomarkers

Answer 1

MALDI is the use of matrix -assisted laser depoinrption ionization as a Mass spectrometry imaging technique in which the sample often a thin tissue section, is moved in two dimesnsions which the mass spectro is recorded.measuring the disribution of a large amount of analyte at one time without destroyingm the sample, it is useful method in tissue -based study.

MALDI involves the visualization of the spatial distribution of proteins, peptides , lipids and other small molecules with inslice of tissue such as animal or plant. it has been able to differentiate between drugs and metabolites and provide histological information in cancer research , which makes it a promising tool for finding Protein bio markers.

MALDI reports a mass to charge ratio(m/z). most molecules have a single charge , so the m/z measurament is equal to the mass of ionization molecules . Most often positive ions are measured , so that the m/z measuring is for the original molecules plus a hydrogen ion. Some times mesure negatively charged ions which are formed by removing a proton from the sample molecule and thus have a M/Z about 1 unit less than the origional molecule.