Decontamination and deodorization of 2,4,6-trichloroanisole on cork

Abstract

The presence of 2,4,6-trichloroanisole (2,4,6-TCA) in cork was identified as a problem for the cork industry in the early 80’s and also considered as a potent compound towards the origin of organoleptic defects in wines. These defects are easily detected by the consumers and it only takes as little as about 5 ng/L to be detected. However, there is a certain difficulty when trying to detect such low concentration levels with mass spectrometry. Heavily contaminating the cork substrates with TCA could be a solution for this detection limitation. By artificially contaminating the samples and by using quadrupole mass spectrometry (QMS) coupled with temperature-programmed desorption (TPD), we verified the presence of a TCA desorption peak in a cork substrate. We also verified that heating above a temperature of 160ºC in a high vacuum atmosphere allows the removal of this contaminant from cork substrates. A TCA quantification method that was developed with this work confirmed that the majority of the TCA was removed with the TPD experiment when heating above the TPD peak. The main outcome of this experiment is the proposed process to remove TCA from cork stoppers by heating at temperatures close or above the TPD peak. Such process would have the goal of making cork and its derivative products free of TCA, or at least below the human detection threshold. In order to achieve this goal, it is necessary to understand how the TCA adsorption occurs, and that will be the objective and the contribution of this thesis work - to confirm the nature of the TCA adsorption and, most importantly, an attempt to determine which group of its molecule is effectively adsorbing onto the cork substrates. For this purpose, other substrates and compounds were chosen to be experimented due to their similarities with the constitution of cork constitution and the chemical structure of TCA, respectively. This experiment showed that cellulose does not have a relevant role in the adsorption process.