How to Process Samples for Metabolomics in Ecology: A Comparative Study of Preanalytical Storage Methods

Area of Science:

• Metabolomics
• Ecological studies
• Analytical chemistry

Background:

• Metabolomics enables understanding organismal responses to environmental factors.
• Preanalytical sample processing effects on metabolic profiles are poorly understood, especially in ecological contexts.
• Field sampling for ecological studies often involves logistical challenges impacting sample integrity.

Purpose of the Study:

• To evaluate the impact of storage duration, temperature, and freeze-drying on metabolic profiles.
• To assess these effects across different biological matrices relevant to ecological studies.
• To provide recommendations for reliable preanalytical sample processing in ecological research.

Main Methods:

• Targeted metabolomics using gas chromatography-mass spectrometry (GC-MS).
• Analysis of 60 metabolites in lesser mealworm, fruit fly, and perennial ryegrass.
• Assessment of samples subjected to varying storage durations (-80°C) and freeze-drying.

Main Results:

• Freeze-drying caused significant metabolic shifts, altering over half of quantified metabolites.
• Several amino acids increased more than fourfold after freeze-drying.
• Metabolic profiles changed gradually over 6 months of storage, even at -80°C.
• Preanalytical and storage effects were consistent across insect and plant matrices.

Conclusions:

• Preanalytical processing, particularly freeze-drying and storage, significantly alters metabolic profiles.
• Standardized protocols are crucial for reliable metabolomics in ecological studies.
• Recommendations are provided to mitigate preanalytical variability considering practical constraints.