For the conditioning of the adsorbents tubes, acetone of HPLC grade (Rotisolve, Carl Roth GmbH + Co KG, (Germany)) was used. The water was self-purified by a MilliQ System. For the enrichment Tenax TA (mesh 60/80) and Tenax GR (mesh 20/35) (Alltech Associates Inc.; Buchem BV (Netherlands)) and silanized glass wool (Sigma Aldrich (Germany)) were used. For tubing Tygon tubes (Carl Roth GmbH + Co KG (Germany)) were used. The Nalophan foil from Kalle GmbH (Germany) was used for wrapping.
As standards 2,4-dimethyl-1-heptene (CAS 19549-87-2, 95%) from Combi-Blocks, (+)-α-longipinene (CAS 5989-08-2, ≥99% sum of enantiomers) from Aldrich, (+)-cyclosativene (CAS 22469-52-9, 99%) from Sigma-Aldrich and (−)-trans-caryophyllene from Sigma-Aldrich (all purchased from Merck (Germany)) were used. The standards were dissolved in methanol (Rotisolve ≥ 99.98%; Carl Roth GmbH + Co KG (Germany)). A volume of 50 µl, which corresponds a mass of 100 ng of each standard, were injected on the adsorbents with a microliter syringe (Hamilton). The solvent was dried by pumping ambient air with a flow of 400 ml/min for 4 minutes over the adsorbents tube. In order to exclude contaminations, the drying procedure was carried out with blank adsorbents.
As standards 2,4-dimethyl-1-heptene (CAS 19549-87-2, 95%) from Combi-Blocks, (+)-α-longipinene (CAS 5989-08-2, ≥99% sum of enantiomers) from Aldrich, (+)-cyclosativene (CAS 22469-52-9, 99%) from Sigma-Aldrich and (−)-trans-caryophyllene from Sigma-Aldrich (all purchased from Merck (Germany)) were used. The standards were dissolved in methanol (Rotisolve ≥ 99.98%; Carl Roth GmbH + Co KG (Germany)). A volume of 50 µl, which corresponds a mass of 100 ng of each standard, were injected on the adsorbents with a microliter syringe (Hamilton). The solvent was dried by pumping ambient air with a flow of 400 ml/min for 4 minutes over the adsorbents tube. In order to exclude contaminations, the drying procedure was carried out with blank adsorbents.