An acute taste and odour episode solved by olfactory GC-MS

This paper details the analytical strategy that was used to understand the origin of an acute taste and odour episode that induced the temporary shutdown of a plant serving several million customers in South America. The odour of the drinking water was described by local people as "olive odour". The odour of a first sample was described as green apple, fruity and olive oil by CIRSEE panellists. LLE and CLSA-GC/MS showed that the sample contained high levels of 2,4-ditertbutylphenol. When submitted to olfactory-GC/MS, the LLE extract revealed the presence of an intense sweet-fruity odour that did not match any of the MS peaks. Investigation of a second, more concentrated sample collected during the peak of the episode finally revealed that this main odour was due to 2-ethyl-5,5-dimethyl-1,3-dioxane (2EDD). The cis and trans isomers of 2-ethyl-4-methyl-1,3-dioxolane (2EMD) were also identified, together with a variety of plastic additives or oligomers. These compounds had been spilled by a polyester resin manufacturing plant. The characteristics of these episodes are compared with the rare similar episodes previously reported in the literature.