BS ISO 16632:2021 pdf download – Tobacco and tobacco products — Determination of water content — Gas-chromatographic method

BS ISO 16632:2021 pdf download – Tobacco and tobacco products — Determination of water content — Gas-chromatographic method Weigh (5,0 ± 0,25) g of the sample (8.1) into the dry extraction vessel (6.1). Record the weight to the nearest 0,000 1 g. It is recommended that a minimum of two test portions be prepared and analysed for each test sample. The recommended procedure for portioned products such as snus is to analyse the entire portion by cutting the pouch in half and adding the tobacco and pouch material to the extraction vessel. Pipette 100,0 ml of extraction solution (5.5) into the extraction vessel and immediately seal the vessel. Place the extraction vessel in the shaker (6.2) and shake for 3 h. Remove the extraction vessel from the shaker and set it aside overnight. The test portions should be gently swirled or mixed mechanically prior to removal of the analysis aliquot. Assemble a disposable syringe (6.3) with a 0,45 µm filter (6.3). Carefully transfer about 5 ml of the supernatant liquid into the disposable filtration assembly. Purge the filter of adsorbed water by disposing of a small volume of the extract. Filter the extract into a 2 ml GC injection vial and cap the vial. Store the filtered extract in a refrigerator below 4 °C until GC analysis, making certain of tight seals. If the extract is not analysed on the same day, store in a refrigerator. The sample shall be allowed to equilibrate to ambient conditions prior to analysis. 8.3 Setting up the apparatus Set up the apparatus and operate the gas chromatograph (6.5) in accordance with the manufacturer’s instructions. Ensure that the peaks for water, internal standard and solvent are well resolved. Condition the system just prior to use by injecting two 0,5 µl aliquots of the extraction solution as a primer. Suitable operating conditions are as follows: — carrier gas: helium; — linear velocity: 30 cm/s at 50 °C; — injection temperature: 250 °C; — injection liner: appropriate liner packed with glass wool; — injection mode: splitless (split valve closed during injection, to be opened after about 1 min); — injection volume: 0,5 µl; — initial temperature: 60 °C; — initial hold time: 0 min; — temperature ramp A: 5 °C/min; — final temperature A: 130 °C; — final hold time A: 0 min; — temperature ramp B: 10 °C/min; — final temperature B: 170 °C; — final...