References & FAQs



Is the extraction protocol different for GC and LC samples?
Extraction methods differ depending on the metabolites to be analyzed and, in some cases, the instrument that will be used to analyze them. For detailed instructions, please contact our facility so that we may guide you through the process.

Is it possible to run the same set of samples on both the GC and the LC?
If you have already performed derivatization for GC analysis, the same samples may not be run on the LC. However, it is possible to aliquot your samples for GC and LC prior to derivatization. Please contact our facility if you wish to do this, and we will guide you through this process.

What if I do not have a SpeedVac to dry my samples?
If you are on the UTSW campus, please contact our facility, and we will schedule a time for you to come dry your samples in our facility. If you are not on the UTSW campus, you may ship your extracted samples in screw-top vials to our facility, and we will dry your samples for you.

At what temperature should I store my samples?
After extraction and drying of your samples, they should be stored at -80°C. Metabolites stored in this manner should be stable for at least two months.

Where can I drop off my samples?
If you are on the UTSW campus, you may drop your samples off in the DeBerardinis lab (NL 11.1120H).  If you are not on the UTSW campus, please ship your dried samples to:

Children’s Research Institute
UT Southwestern Medical Center
Attn: Lauren Zacharias
6000 Harry Hines Blvd
Room NL 11.120G
Dallas, TX 75390-8502

What is the difference between MRM and full-scan data?
Multiple Reaction Monitoring (MRM) is performed on a triple-quadrupole mass spectrometer and only detects the metabolites that the user programs the instrument to monitor. Full-scan data sets, including data acquired on high-resolution mass spectrometers, include all detected ions with no need to pre-select which metabolites to monitor.

What is TIC normalization?
In this method of normalization, the peak area of each metabolite is normalized against the sum of all peak areas detected by the mass spectrometer in that sample.

What statistical tools are available to analyze my data?
Any statistical software can analyze the peak areas that are returned to you. Commonly used software packages include GraphPad, MetaboAnalyst, SIMCA, R, etc.