Figure 5From: The MetabolomeExpress Project: enabling web-based processing, analysis and transparent dissemination of GC/MS metabolomics datasetsPoor 'concentration:signal intensity' correlation for glutamine (3TMS) was due to its time-dependent consumption by an unknown chemical process. The graph above shows the relationship between Glutamine (3TMS) signal intensity and time of analysis for 5 derivatised samples each originally supplied with the same amount of glutamine (450 pmol/μl). All samples were derivatised at the same time so a later time of analysis corresponds to a greater sample age.Back to article page