Analysis of glycerol bound ω-oxo-fatty acids as ω-dioxane-FAME-derivatives

ω-oxo-fatty acids, also known as aldehydic fatty acids, are major products of fatty acid oxidation and pose potential health risks. When bound to glycerol, ω-oxo-fatty acids (core aldehydes) can be ingested with food. Challenges in GC–MS quantification include the absence of an appropriate internal standard. Additionally, substantial analyte losses during sample preparation, caused by the high volatility of short-chain compounds, alter their pattern based on molecular weight. In this study, among various tested derivatization methods, the formation of ω-dioxane derivatives demonstrated improved recovery rates after three evaporation cycles. For methyl 7-oxo-heptanoate, recovery increased from 43 % to 88 %, while recovery rates for different chain lengths and a novel synthesized internal standard improved from a range of 43 %–76 % to 87 %–92 %. Additionally, ω-dioxane derivatives displayed favorable GC–MS behavior, enabling clear identification and increased sensitivity. Finally, ω-oxo-fatty acids were quantified as their ω-dioxane-derivatives in thermally treated sunflower and rapeseed oil. • Quantification of ω-oxo-fatty acids with a newly synthesized internal standard. • Innovative derivatization method for short chain ω-oxo-fatty acids. • Significant mitigation of evaporation losses and pattern change of ω-oxo-FAMEs. • Analytes after derivatization: Clear identification and enhanced sensitivity. • Quantification of ω-oxo-fatty acids in heated sunflower and rape seed oil by GC–MS.