Determination of non-polar heterocyclic aromatic amines in roasted coffee by SPE-HPLC-FLD

The non-polar heterocyclic aromatic amines (HAAs) are formed as pyrolysis products of amino acids at higher temperatures. Green coffee beans were roasted at 240 degrees C from 5 to 14.5 min (four levels). Solid-phase extraction coupled to high-performance liquid chromatography with fluorescence detection (HPLC-FLD) was used for identification and quantification of five HAAs (Glu-P 2, Glu-P 1, Phe-P 1, A alpha C, and MeA alpha C) in roasted coffee. The excitation and emission wavelength program was optimized for non-polar HAAs. The analytes were eluted with eluent A (76% water, 14% acetonitrile, 8% methanol, and 2% acetic acid; pH = 5) and B (acetonitrile) in gradient mode. The limits of detection for non-polar HAAs were in the range of 0.21-0.51 ng/g, the limits of quantification from 0.38 to 0.93 ng/g with a recovery of 40-56%. From the tested HAAs, only A alpha C was present in roasted coffee; Glu-P 2, Glu-P 1, Phe-P 1, and MeA alpha C were not found in any coffee sample.