Migration of 2,4,6-trichloroanisole from cork stoppers to wine

Abstract

The migration of 2,4,6-trichloroanisole (TCA) from cork stoppers to wine is studied under different experimental conditions. Corks that were either naturally contaminated or spiked with a TCA solution were immersed in an ethanol–water mixture (12% v/v) for 6 days or were used as a closure for bottled wines over periods of 1, 4 and 8 months. The TCA content was determined after the stated periods using headspace solid-phase microextraction and gas chromatography electron capture detection. Three different spiking procedures were tested: the injection of a TCA solution into the cork, the immersion of the cork in a TCA in hexane solution, and cutting off a thin slab to inject different quantities of a TCA solution into it before rejoining the two parts. Only the first of these procedures was subsequently used as the immersion technique failed to retain sufficient quantities of TCA and the slab technique retained too much. Corks spiked with 120 ng TCA gave 8% migration after 6 days for corks used in the immersion experiments and less than 1% migration for corked bottles kept for 1 month. When the contact time was 4 and 8 months, migration was 4 and 8% respectively for corks spiked with 1 μg TCA. It was concluded that the contact surface, temperature and time all favour TCA migration. Under the same conditions, wine bottled with naturally contaminated cork stoppers showed TCA concentrations which varied depending on the characteristics of every individual cork stopper.