Lipid Extraction Techniques for Stable Isotope Analysis and Ecological Assays

Protocol
Part of the Methods in Molecular Biology book series (MIMB, volume 1609)

Abstract

Lipid extraction is an important component of many ecological and ecotoxicological measurements. For instance, percent lipid is often used as a measure of body condition, under the assumption that those individuals with higher lipid reserves are healthier. Likewise, lipids are depleted in 13C compared with protein, and it is consequently a routine to remove lipids prior to measuring carbon isotopes in ecological studies so that variation in lipid content does not obscure variation in diet. We provide detailed methods for two different protocols for lipid extraction: Soxhlet apparatus and manual distillation. We also provide methods for polar and nonpolar solvents. Neutral (nonpolar) solvents remove some lipids but few non-lipid compounds, whereas polar solvents remove most lipids but also many non-lipid compounds. We discuss each of the methods and provide guidelines for best practices. We recommend that, for stable isotope analysis, researchers test for a relationship between the change in carbon stable isotope ratio and the amount of lipid extracted to see if the degree of extraction has an impact on isotope ratios. Stable isotope analysis is widely used by ecologists, and we provide a detailed methodology that minimizes known biases.

Key words

Lipid extraction Stable isotope analysis Polar lipids Neutral lipids Soxhlet apparatus Ecophysiology Ecotoxicology Diet reconstruction 

Notes

Acknowledgments

The protocol is based on a text developed by I. Burron and D. Mocker. Funding for sample preparation equipment was provided by the Canada Foundation for Innovation.

Supplementary material

371854_1_En_2_MOESM1_ESM.docx (48 kb)
Elliott-Elliot_Figure (DOCX 48 kb)

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Copyright information

© Springer Science+Business Media LLC 2017

Authors and Affiliations

  1. 1.Department of Natural Resource SciencesMcGill UniversityQuebecCanada
  2. 2.Department of Biological SciencesUniversity of ManitobaWinnipegCanada

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