Investigation of the effects of storage and freezing on mixes of heavy-labeled metabolite and amino acid standards.

摘要: Rationale High-throughput metabolomics has now made it possible for small/medium-sized laboratories to analyze thousands of samples/year from the most diverse biological matrices including biofluids, cell and tissue extracts. In large-scale studies, stable-isotope-labeled standards are increasingly used normalize matrix effects control technical reproducibility (e.g. extraction efficiency, chromatographic retention times mass spectrometry signal stability). However, is currently unknown how stable mixes commercially available following repeated freeze/thaw cycles or prolonged storage aliquots. Methods Standard 13 C, 15 N deuterated isotopologues amino acids key metabolites central carbon nitrogen pathways glycolysis, Krebs cycle, redox homeostasis, purines) were either repeatedly frozen/thawed up 10 diluted into aliquots prior frozen 42 days. Samples characterized by ultra-high-pressure liquid chromatography/mass determine stability aliquoted upon freezing/thawing storage. Results Metabolite over cycles, with exception adenosine glutathione, showing variability across in a freeze/thaw-cycle-independent fashion. Storage days did not significantly affect acid metabolite first 2 weeks, while progressive degradation (statistically significant fumarate) was observed after 3 weeks. Conclusions Refrigerated preservation at least weeks heavy-labeled standard analysis feasible time-/resource-saving strategy laboratories.