Article de Florence Lacoste, Responsable Département Analyse et Expertise de l’ITERG, publié dans European Journal of Lipid Science and Technology, juin 2015
An interlaboratory study was conducted in 2014 to evaluate a method for determining mineral oil saturated hydrocarbons in vegetable oils and fats. Samples were dissolved in an apolar solvent and subjected to a purification on silica gel impregnated with silver nitrate. The final extract was analyzed using gas chromatography with a flame ionization detection. Quantification was performed using internal standardization. Six samples were assayed for mineral oil saturated hydrocarbons by 21 collaborating laboratories from nine countries. Sample matrices included olive, olive pomace, sunflower, soybean and rapeseed oils. Comparing two types of integration of the unresolved complex mixture area, it was decided to recommend in the test method the integration of the natural hydrocarbons only considering the highest peaks of n-alkanes. Repeatability (RSDr) ranged from 3.7 % to 10.5 % and reproducibility (RSDR) ranged from 10.3 % to 25.7 % for samples containing greater than 35 mg/kg of mineral oil saturated hydrocarbons. The method provides acceptable results for quantification of mineral oil saturated hydrocarbons in edible oils, from 50 mg/kg to 1000 mg/kg.
Practical application : Since now, standardized methods for mineral oil saturated hydrocarbon determination in vegetable oils and fats, are not yet available. This paper describes the validation of a method for the quantification of the saturated aliphatic hydrocarbons and it provides the results from an international collaborative trial.