We have quantified the amounts of glutamine and glutamic acid in pancreatic islets from diabetic and non-diabetic mice under different conditions related to insulin hypersecretion. We optimized the sample preparation and employed LC-MS with HILIC separation followed by TOF-MS. By spiking with a C-13 labeled internal standard, we obtained excellent quantitative results for these two amino acids for very small sample amounts (down to single islets). In addition, we observed numerous other metabolites (e.g. most of the amino acids). Along with this metabolic profiling study, we have been working on some instrumentation development to benefit metabolomics. Briefly, it involves a new type of ion source with an electrospray-type mechanism that should improve ionization efficiency and reduce ion suppression for metabolite mixtures. By improving MS analysis of mixtures, we hope to reduce LC run times as well as observe and identify additional metabolites.