Evaluation of solutions for stabilizing feces in metabolomics studies using GC × GC-TOFMS.

Introduction: Fecal metabolomics studies have garnered interest in recent years due to the potential for these samples to provide unique information about an individual. Stool is a dynamic mixture of human excrement, microbiota, and enzymes that yields a constantly changing metabolite profile. The main challenge in a fecal metabolomics study is ensuring that the metabolite profile changes as little as possible between sample collection and sample processing/analysis.

Objectives: This study aimed to evaluate the efficacy of five solutions in preserving human fecal metabolites over a seven-day storage period at ambient temperature, enabling at-home collection, cost-effective ambient transport and sample storage.

Method: Five solutions with varying chemical compositions were evaluated for their ability to stabilize fecal metabolites. Samples were stored at ambient temperature for seven days, and metabolites were analyzed using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC × GC-TOFMS). The stabilizing efficacy of the solutions was assessed using total useful peak area (TUPA), absolute relative change (ARC) and compound class-based analyses, comparing the initial, stabilized, and unstabilized samples.

Results: Different solutions demonstrated varied efficiencies for different compound classes. Overall, the results indicated that the use of stabilization solutions significantly minimized changes in the fecal metabolite profile compared to unstabilized samples left at room temperature for one week.

Conclusion: This study demonstrates that stabilization solutions are effective in preserving fecal metabolites during storage at ambient temperature, supporting the feasibility of at-home sample collection.