Development of a solid-phase extraction method for the simultaneous determination of chloroanisoles and chlorophenols in red wine using gas chromatography-tandem mass spectrometry

A procedure for the determination of three chloroanisoles (2,4,6-trichloro, 2,3,4,6-tetrachloro and pentachloroanisol), as well as their precursor chlorophenols (2,4,6-trichloro, 2,3,4,6-tetrachloro and pentachlorophenol), involved in the presence of cork taint in red wine has been developed. Samples, up to 1 l, were concentrated using a 200 mg Oasis HLB solid-phase extraction (SPE) cartridge. Chlorophenols were quantitatively eluted from this sorbent with 3 ml of methanol. Chloroanisoles were mainly recovered in a second fraction of n-hexane (2 ml). Both fractions were combined and mixed with an aqueous solution of sodium bicarbonate and 50 μl of acetic anhydride. Chlorophenols were acetylated in the aqueous-methanolic phase and extracted to n-hexane. Chloroanisoles remained unaffected in the n-hexane layer. Both groups of compounds were determined by gas chromatography-tandem mass spectrometry in the same chromatographic analysis. Using a temperature programmable vaporization injector detection limits from 0.2 to 2.4 ng l−1, below their sensorial threshold level in red wine, were obtained for all compounds. Average recoveries higher than 80% and acceptable precision were achieved using red wine samples spiked with the analytes at different concentration levels.