title: ASE extraction method for simultaneous carbon and nitrogen stable isotope analysis in soft tissues of aquatic organisms.
abstract: Since lipids are depleted in 13C relative to proteins and carbohydrates, variations in lipid composition among species and within individuals significantly influence delta13C and may result in misleading ecological interpretations. Whereas lipid extraction before IRMS analysis constitutes a way of stable isotope result lipid-normalisation, such a procedure was given up because of the un-controlled effects of the methods used (i.e., "Bligh & Dyer", Soxhlet, etc.) on delta15N. The aim of this work was to develop a simple, rapid and efficient lipid extraction method allowing for simultaneous C and N stable isotope analysis in the biological soft tissues of aquatic organisms. The goal was to be free from the lipid influence on delta13C values without interfering with delta15N values. For that purpose, the modern automated pressurized liquid extraction technique ASE (accelerated solvent extraction) was selected. Eel muscles representative of a broad range of fat contents were extracted via ASE by using different semi-polar solvents (100% dichloromethane and 80% n-hexane/20% acetone) and by operating at different temperature (ambient temperature and 100 degrees C) and pressure (750 and 1900 psi) conditions. The results were discussed in terms of lipid extraction efficiency as well as delta13C and delta15N variability.
authors.affiliation: ISM/LPTC, UMR 5255 CNRS, Université de Bordeaux 1, 351 Cours de la Libération, 33405 Talence, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: Bodin
authors.forename: Hélène
authors.initials: H
authors.lastname: Budzinski
authors.forename: Karyn
authors.initials: K
authors.lastname: Le Ménach
authors.forename: Nathalie
authors.initials: N
authors.lastname: Tapie
mesh_terms: D000811:Anguilla; D000818:Animals; D002247:Carbon Isotopes / Q000032:analysis*; D005591:Chemical Fractionation / Q000379:methods*; D008055:Lipids / Q000032:analysis*; D018482:Muscle, Skeletal / Q000737:chemistry*; D009587:Nitrogen Isotopes / Q000032:analysis*; D011312:Pressure; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D002247:Carbon Isotopes; D008055:Lipids; D009587:Nitrogen Isotopes; D012997:Solvents