The use of quality
control samples in metabolomics ensures data
quality, reproducibility, and comparability between studies, analytical
platforms, and laboratories. Long-term, stable, and sustainable reference
materials (RMs) are a critical component of the quality assurance/quality
control (QA/QC) system; however, the limited selection of currently
available matrix-matched RMs reduces their applicability for widespread
use. To produce an RM in any context, for any matrix that is robust
to changes over the course of time, we developed iterative batch averaging
method (IBAT). To illustrate this method, we generated 11 independently
grown Escherichia coli batches and
made an RM over the course of 10 IBAT iterations. We measured the
variance of these materials by nuclear magnetic resonance (NMR) and
showed that IBAT produces a stable and sustainable RM over time. This E. coli RM was then used as a food source to produce
a Caenorhabditis elegans RM for a metabolomics
experiment. The metabolite extraction of this material, alongside
41 independently grown individual C. elegans samples of the same genotype, allowed us to estimate the proportion
of sample variation in preanalytical steps. From the NMR data, we
found that 40% of the metabolite variance is due to the metabolite
extraction process and analysis and 60% is due to sample-to-sample
variance. The availability of RMs in untargeted metabolomics is one
of the predominant needs of the metabolomics community that reach
beyond quality control practices. IBAT addresses this need by facilitating
the production of biologically relevant RMs and increasing their widespread
use.