Determination of Polycyclic Aromatic Hydrocarbons in Coffee and Coffee Substitutes using Dispersive SPE and Gas Chromatography-Mass Spectrometry

Abstract

The purpose of this study was to evaluate the application of dispersive solid-phase extraction with the use of primary secondary amine (PSA), NH2 and strong anion exchange (SAX) sorbents for polycyclic aromatic hydrocarbon (PAH) determination in samples of coffee. The final extracts were analysed by gas chromatography selected ion monitoring mass spectroscopy (GC-SIM-MS). The results indicated that cleanup with PSA and SAX sorbents followed by final solvent exchange from acetonitrile to hexane (liquid–liquid extraction, LLE) was the best variant of the method, resulting in the cleanest extracts and satisfactory compound recoveries (70–104 %) for examined compounds in coffee samples. In the study of real samples, the concentrations of PAH markers (benzo[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[a]pyrene) were higher for natural roasted coffee (7.20–68.15 μg kg −1), than for instant coffee (2.97–19.55 μg kg −1) and cereal coffee (8.15–15.35 μg kg −1), and the sum of PAHs was also higher in natural and instant coffees compared to coffee substitutes (364, 343 and 265 μg kg −1, respectively). However, in all samples of coffee, light (three-ring) PAHs dominated within the identified compounds and phenanthrene was the most abundant compound, approaching 209.67 μg kg −1 in roasted coffee.