Monitoring dynamic changes in lymph metabolome of fasting and fed rats by matrix-assisted laser desorption/ionization-ion mobility mass spectrometry (MALDI-IMMS)

Matrix-assisted laser/desorption ionization (MALDI) time-of-flight mass spectrometry (TOF) has been investigated for use in the field of metabolomics; however, difficulties, mainly due to chemical interferences, are typically encountered. By coupling MALDI with ion mobility time-of-flight mass spectrometry (IMMS), isomers and isobars are resolved in mobility space reducing the chemical interference from matrix/background ions. MALDI-IMMS offers the advantages of high sensitivity, high throughput and low sample consumption. For this study, MALDI-IMMS was evaluated by monitoring metabolic changes in lymphatic fluid collected from fasting and fed rats. The number of metabolite features detected in the samples ranged between 1200 and 3400 depending on the duration between the feeding time and lymph sample collection. There were 747 metabolite features that were statistically analyzed by principal component analysis (PCA). From the 3-D score plots of PC1, PC2 and PC3 65 % of the original variation of the system was explained and the differences between the samples were demonstrated.