γ hexalactone

The maceration to extract the volatile compounds from sawdust was done based on the procedure described by Chatonnet et al., 1999 . The sawdust samples (2 g) were soaked in 100 ml of hydroalcoholic solution (12% v/v ethanol, 6 g/l tartaric acid, pH 3.2) for 15 days at a room temperature of 20ºC and in darkness. The mixture (approximately 80 ml depend on the wood) were filtered using cellulose filters grade 2 (Whatman, Sigma-Aldrich, Steinheim, Germany). Fifty ml of this were taken and 300 µl of five internal standards (γ-hexalactone, 2-octanol, 4,5-dimethylfurfuraldehyde, o-vanillone, and 3,4-dimethoxyphenol in a dose of 0.5 mg/ml in ethanol) (Sigma-Aldrich, Steinheim, Germany) were added. This mixture and the standards were then extracted following a previously reported methodology (López, Aznar, Cacho & Ferreira 2002) for which prepacked cartridges (total volume 3 ml) filled with 200 mg of LiChrolut EN resin (Merck, Darmstadt, Germany) were used. For this, the fifty ml of the mixture were passed through the SPE cartridges at 2 ml/min. Subsequently, the sorbent was dried by letting air pass through it at approximately -0.6 Bar during 30 min. The resulting analytes were recovered by elution with 1.3 ml of dichloromethane.