The application of multistep extraction and liquid chromatography with fluorescence detection for analysis of azaarenes in edible oil samples

A method was adapted for the analysis of 6 azaarenes: benzo[h]quinoline, benzo[a]acridine, benzo[c]acridine, dibenzo[a, c]acridine, dibenzo[a, j]acridine and dibenzo[a, h]acridine, in raw (“recently opened”) and thermally treated edible oils (cold-pressed rapeseed and olive). The purification procedure used was based on alkaline hydrolysis, tandem solid-phase extraction on columns filled with Extrelut – a diatomaceous earth and cation exchanger (propylsulphonic acid). The procedure enabled the selective isolation of potentially carcinogenic compounds belonging to benzoacridines and dibenzoacridines from oil samples. The eluted fractions of azaarenes were analyzed by high-performance liquid chromatography with programmed fluorescence detection. The detection limits for the azaarenes were between 0.0003 and 0.01 ng/g of oil. The recoveries for the analyzed compounds were from 59 to 79%. The concentrations of the individual azaarenes found in the investigated samples were between 0.08 and 2.55 ng/g. The total concentrations of the B[h]Q, benzoacridines and dibenzoacridines (expressed in ng/g of oil) fall within the range of 3.18–3.82 in the “recently opened” sample and from 2.65 to 4.68 in the thermally treated oil samples.