Development of two stable isotope dilution assays for the quantitation of acrolein in heat-processed fats

Two stable isotope dilution assays were developed for the quantitation of acrolein in fats and oils using [¹³C₃]-acrolein as the internal standard. First, a direct GC-MS headspace method, followed by an indirect GC-MS method using derivatization with pentafluorophenyl hydrazine, was established. Analysis of six different types of oils varying in their pattern of fatty acids showed significant differences in the amounts of acrolein formed after heating at various temperatures and for various times. For example, after 24 h at 140 °C, coconut oil contained 6.7 mg/kg, whereas linseed oil was highest with 242.3 mg/kg. A comparison of the results showed that the extent of acrolein formation seemed to be correlated with the amount of linolenic acid in the oils. Although the acrolein concentrations were lowered in all six oils after frying of potato crisps, linseed and rapeseed oil still contained the highest amounts of acrolein after frying. By applying both methods on different thermally treated fats and oils, nearly identical quantitative data were obtained.