1. LC-MS analysis of sample set: Experimental samples spiked with IS and MATRIX. MATRIX is injected periodically i.e. at 10 sample intervals as QC Standard to account for fluctuations in mass and retention time drift.
  2. Generate “dictionary” of RT, m/z, formula and physical characteristics from the analysis of MATRIX using ClusterFinder software.
  3. Use ClusterFinder and dictionary to identify and quantitate compounds in experimental samples
  MATRIX (paired 1:1 mixture of labeled U-5% and - 95% 13C metabolites): used to build a triply redundant   dictionary (library) of RT, m/z and physical characteristics including fragmentation data.

  IROA INTERNAL STANDARD – IS (labeled 95% 13C metabolites only): spiked into experimental samples     and used as a yardstick in which to identify and quantitate metabolites using library.  Even if analyzed on a   different chromatographic system, results can be equated using dictionary because of IS. Compounds may have   different RTs but will exhibit the same mass and physical characteristics.

  ClusterFinder Software

  • Generates "dictionary compiled from Matrix analysis of all LC-MS and MSMS modes
  • Finds and identifies IROA-IS isotopomers spiked into expt samples, co-locates paired natural abundance expt peaks, performs quantitation and normalization
  • Removes unpaired artefacts
  • Uses peak correlation analysis to find all possible correlated adducts and fragments

IROA ID-QUANT-QC Workflow ensures high level QC for accurate and reproducible results and enables comparison of data across time and instruments 


For background reading: WHITEPAPER - Challenges in Metabolomics Analysis (and a solution)