ISO 16632:2013 pdf free

ISO 16632:2013 pdf free.Tobacco and tobacco products一Determination of water content一Gas-chromatographic method
Prepare a series of at least four calibration solutions whose concentrations of added water cover the range expected to be found in the test portion by adding weighed amounts of water (5.4) to the solvent (5.5).
One of these calibration solutions shall be the extraction solvent with no added water (solvent blank).To prevent water being absorbed, the bulk solvent container shall be fitted with a water trap and all solutions shall be kept sealed. The solvent shall be stirred continuously to ensure the homogeneity of the water concentration in the solvent. The calibration solutions shall be made up using an extraction solvent from the same batch used in 8.1. Transfer them to injection vials and cap immediately.
It is recommended that the calibration solutions be made up at least each week.
NOTE For example, calibration solutions may be prepared as follows. Create a stock standard solution by accurately weighing (to the nearest 0,1 mg) 25,000 g of water into a dry 500 ml volumetric flask. Dilute the water with extraction solvent (5.5) to the 500 ml mark. Pipette 0 ml, 5 ml, 10 ml, 20 ml, 30 ml, 40 ml, 50 ml and 60 ml of the stock standard water solution into each of eight dry 100 ml volumetric flasks. Dilute to volume with extraction solvent (5.5). The standard calibration solutions contain 0,0 mg, 2,5 mg, 5,0 mg, 10,0 mg, 15,0 mg,20,0 mg, 25,0 mg, and 30,0 mg of water per millilitre of extraction solvent.
Weigh, to the nearest 0,1 mg, 5,0 g of the sample (8.1) into the dry extraction vessel (6.1). A minimum of two test portions shall be prepared and analysed for each test sample.
Pipette 100,0 ml of extraction solvent (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 intoa 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. After conditioning to room temperature, the extract should be analysed.ISO 16632 pdf download.