Optimization of sample clean-up for the determination of small amounts of MOSH and MOAH in edible oils – method DGF C-VI 22 (20)

Abstract

Methods for determining MOSH and MOAH in edible oils showed major problems with interlaboratory comparability of analytical results, especially in the lower concentration range below 10 mg/kg. However, a method with improved sensitivity and reproducibility is urgently needed to obtain a valid data basis for minimization efforts. To cope this problem a new method was created in 2020. The method was established as the standard method DGF C-VI 22 (20) of the German Society for Fat Science e.V. (DGF). For the development of this method different sample epoxidation approaches have been performed, evaluated and improved. Additionally, a saponification, a decision tree for sample preparation, an upstream clean-up column and a system suitability test were introduced. The focus was on reliability and interlaboratory comparability over all edible oil matrices up to a LOQ of 1 mg/kg. The optimized method was validated in terms of trueness and precision in a collaborative trail with 11 laboratories. The achieved recovery rates of 89–105% MOSH and 70–105% MOAH met the JRC requirements. Method and validation results were obtained with HorRat values between 1.3 and 1.8 for MOSH and MOAH.

Keywords:

• MOSH
• MOAH
• mineral oil
• LC-GC-FID
• epoxidation
• edible oil
• standard method
• method validation

Acknowledgments

The authors would like to thank all participants and contributors of the MOxH think tank and all participants of the collaborative trial: A. Walzl, TU Graz, Austria;T. Püth, J. Menzel and C. Goldbeck, Chemisches und Veterinäruntersuchungsamt Münsterland-Emscher-Lippe, Germany; V. Koospal, Chemisches und Veterinäruntersuchungsamt Stuttgart, Germany; F. Janusch, Eurofins WEJ Contaminants GmbH, Germany; S. Sievers and C. Wedekind, GALAB laboratories GmbH, Germany; E. Becker and S. Kühn, Institut Kirchhoff Berlin GmbH, Germany; S. Horst, Landesuntersuchungsanstalt für das Gesundheits- und Veterinärwesen Sachsen LUA, Germany; A. Stauff, Lebensmittelchemisches Institut des Bundesverbandes der deutschen Süßwarenindustrie e.V., Germany; T. Funke, Münster Analytical Solutions GmbH, Germany; S. Losa, SGS Institut Fresenius GmbH, Germany. The authors would like to additionally thank the following participants for their extraordinary commitment: P. Tablack, Axel Semrau GmbH & Co. KG, Germany, for planning, organisation and moderation of the MOxH think tank; B. Schindler, PROOF-ACS GmbH, Germany, for the production of test samples and the statistical analysis. Many thanks also go to Jessica Thöne, Jared Solty and Maximilian Koch of the Max Rubner-Institute for their excellent technical assistance and her conscientious support in the laboratory.

Additional information

Funding

The author Albert C received funding for the IGF project (AiF 19662 N). This IGF project (AiF 19662 N) of the FEI was supported via AiF within the program for promoting the Industrial Collective Research (IGF) of the German Ministry of Economics and Energy (BMWi) based on a resolution of the German Parliament.