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

Abstract

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 °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, AαC, and MeAαC) 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 AαC was present in roasted coffee; Glu-P 2, Glu-P 1, Phe-P 1, and MeAαC were not found in any coffee sample.