Imaging mass spectrometry (IMS) methodology for biological tissue component distribution map using MALDI-TOF MS and MALDI-TOF/TOF MS was established.Peak density distribution was probed to be quite useful for MS image classification.More than 40 000 spectra from 200 tissue sections were acquired and reproducibility between various of species groups was great than 80%.Tens of differentiately expressed components were detected by t-test (P<0.01).Classification modeling was created based on the differentiate components,blind species were analyzed for model validation,accuracy was above 90%.
In order to extract peptides from formalin-fixed tissue and compare the peptide profile differences between control group and disease group,different antigen retrieval(AR) methods were investigated in this paper: organic solvent,trypsin and magnetic bead.MALDI-TOF MS was used for evaluating the retrieval efficiency.Results showed: trypsin retrieval method was compatible to MS analysis and the higher quality spectra could be acquired,the time of digestion did not affect the peptide profile but the concentration was crucial.We concluded the optimal conditions as follows: digestion with 0.1μg/μL of trypsin at 37℃ for 2h and using the of α-cyano-4-hydroxy cinnamic acid as the MALDI matrix.
A protocol for serum peptidomics using peptide electrophoresis combining with mass spectrometry was reported in this paper.Results showed that the improved peptide electrophoresis and MALDI-TOF MS could evaluate the efficiency of serum peptide processing methods.Our protocol was verified with a high reproducibility.
