Ionic matrices pre-spotted matrix-assisted laser desorption/ionization plates for patient maker following in course of treatment, drug titration, and MALDI mass spectrometry imaging

In the current study, we compared plastic matrix-assisted laser desorption/ionization (MALDI) plates pre-spotted with different solid ionic matrices. Data reflect that after 3 months of storage, the standards were oxidized in α-cyano-4-hydroxycinnamic acid (HCCA) whether or not in HCCA/3-acetylpyridine (3APY) and HCCA/aniline, and certain peptides, such as ubiquitin, were not detected using the HCCA matrix, whereas they were detected in pre-spotted ionic matrices. Application in peptidomics of these MALDI matrices pre-spotted plates (after 3 months of storage) with ovarian cyst fluid showed less intense signals with HCCA than with solid ionic matrices. We show that these pre-spotted ionic matrices plates can be used for relative drug quantification, high mass protein detection, and MALDI mass spectrometry imaging.