Study of current analytical strategies for the dual investigation of polycyclic aromatic hydrocarbons and benzene, toluene, ethylbenzene and xylene in apples

This study aimed at developing a versatile strategy for the dual determination of polycyclic aromatic hydrocarbons (PAHs) and benzene, toluene, ethylbenzene and xylene (BTEX) in apples. For that, the headspace-solid-phase microextraction (HS-SPME) method was first optimized with the aim to extract all the target compounds. A carboxen/polydimethylsiloxane fibre associated with a duration of 45 min and a temperature of 60 °C was the most suitable condition for the extraction of BTEX and low molecular weight PAHs. Combined to a functional gas chromatography-mass spectrometry (GC-MS) method, recovery above instrumental detection limits (>0.14 μg) and high extraction reproducibility (relative standard deviation <15%) were obtained for every compound. Solid-phase extraction (SPE), ultrasound assisted extraction (UAE) and Soxhlet were then evaluated focusing on their ability to extract the four to six-ring PAHs. Associated to an accurate GC-MS method, UAE showed the best extraction recoveries (up to 1.96 μg out of 2 μg), and a good linearity (R2 > 0.95) and detection limit below 0.26 μg were obtained for all these compounds. This study points out the real difficulty to find a single procedure for the dual investigation of volatile and non-volatile analytes in complex foodstuffs like apples.