Filter-vial dispersive solid-phase extraction as a simplified clean-up for determination of ethylphenols in red wines

In-vial filtration with dispersive solid-phase extraction (d-SPE) clean-up of QuEChERS (quick, easy, cheap, effective, rugged and safe) extracts is proposed for the determination of ethylphenols (EPs) in red wines. Analytes were extracted from 5mL wine sample (previously alkalinized with 0.5% sodium hydroxide) using 5mL acetonitrile. For phase separation, 1.5g NaCl and 4g anhydrous MgSO₄ were added. Then, a 0.5mL aliquot of the partitioned supernatant was cleaned-up using d-SPE and in-vial filtration with a combination of anhydrous CaCl₂ (100mg) and primary-secondary amine (PSA, 25mg) as sorbents. The proposed method provided limits of quantification (LOQs) ranging from 0.024 to 0.04mgL^-1. Considering matrix-matched calibration as quantification technique, the recoveries (accuracy) ranged between 73% and 116%. The method was applied for the determination of EPs in 15 commercial wines of Argentina, where 4-EP was quantified at concentrations ranging from 0.25 to 3.01mgL^-1.