Analysis of PAHs in Brazilian coffee by combining QuEChERS and LD-DLLME

Abstract

The presence of polycyclic aromatic hydrocarbons (PAHs) in food is a growing concern due to their toxicological potential. Considering the possible occurrence of these compounds in coffee, one of the most widely consumed beverages worldwide, this study aimed to estimate the levels of 13 PAHs in roasted and ground coffee samples sold in Brazil. A sensitive and accurate method using gas chromatography-mass spectrometry (GC-MS) was employed. Sample preparation included QuEChERS-based extraction, followed by liquid-liquid dispersive microextraction (LD-DLLME) with a low-density solvent for analyte enrichment. A Plackett-Burman experimental design was applied to evaluate the influence of preparation variables on PAH extraction, identifying water volume as the most significant factor. Method suitability was confirmed through selectivity, linearity (≥0.99), recovery (83.2–119.5 %), and precision (RSD ≤12 %). The validated method was applied to 28 commercial coffee samples, of which 11 contained PAHs, with concentrations ranging from 21 µg kg⁻¹ (benzo[a]pyrene and indeno[1,2,3-c,d]pyrene) to 133 µg kg⁻¹ (dibenzo[a,h]anthracene). The most frequently detected compounds were indeno[1,2,3-c,d]pyrene, chrysene, benzo[g,h,i]perylene, and benzo[a]pyrene. Environmental and safety aspects for analysts were evaluated using the Eco-Scale tool, classifying the method as an acceptable green analysis. The developed method proved effective for detecting and quantifying PAHs in coffee.