BS ISO 16632 pdf free download

BS ISO 16632-2021 pdf free download.Tobacco and tobacco products – Determination of water content一Gas-chromatographic method.
6 Apparatus
Usual laboratory apparatus and, in particular, the following items.
All glassware used in the preparation and in the water determination shall be prepared to remove any water residue. Volumetric glassware shall be air-dried and stored in a desiccator over desiccant (5.6) until used. All other glassware shall be heated at (105 ± 5) °C for at least 1 h after visible water has evaporated. The glassware shall then be cooled and stored in a desiccator over desiccant (5.6) until used.
6.1 Extraction vessels, for example of capacity 125 ml, dry serum bottles with crimp caps, or conical
flasks with ground glass lids, or equivalent.
It is especially important to have excellent seals to prevent water absorption from air exposure.
6.2 Shaker, preferably horizontal, but wrist-action acceptable.
6.3 Disposable syringes, equipped with membrane filters with 0,45 urn pore size, or equivalent.
6.4 Volumetric flasks, for example of capacities 100 ml and 500 ml, necessary for the preparation of
the water stock solution (522) and the calibration standard solutions (5.73).
6.5 Gas chromatograph, equipped with a thermal conductivity detector, autosampler, and data
acquisition system.
6.6 Column, a PLOT fused silica column has been demonstrated to be acceptable with PoraPLOT
Li2) stationary phase (20 pm film thickness), 25 m in length with 0,53 mm internal diameter (see also
Clause 11).
6.7 Hot-air oven, capable of maintaining a temperature of (105 ± 5) °C.
7 Sampling
Sampling is conducted such that the laboratory test sample is representative of the population to be tested.
8 Procedure
8.1 Sample handling
It is recommended to combine and mix enough retail units to constitute at least 100 g for each test subsample. If size reduction is employed, the sample should be cut sufficiently small to pass through a 4 mm screen. The sample may be frozen with liquid nitrogen before cutting if the absolute moisture level is of interest. Cut filler from cigarettes need not be reduced further in size.
8.2 Sample preparation
Allow for adequate head space in the extraction vessel to increase extraction efficiency.
The sample weight and extraction volume may be adjusted on condition that it does not affect the
determination.
2) PoraPLOT U with 20 pm film thickness is an example of a suitable product commercially available. This information is given for the convenience of users of this document and does not constitute an endorsement by ISO of this product. Equivalent columns may be used if they can be shown to lead to the same results, i.e. that the analytes and internal standards are sufficiently resolved from interferences.
Weigh (5,0 ± 0,25) g of the sample (IU) into the dry extraction vessel (6J.). 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 (55) 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 pm filter (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 i.tl 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 mm);
— injection volume: 0,5 p1;
— initial temperature: 60 °C;
— initial hold time: 0 mm;
— temperature ramp A: 5 °C/min;
— final temperature A: 130 °C;
— final hold time A: 0 mm;
— temperature ramp B: 10 °C/min;
— final temperature B: 170 °C;
— final hold time B: 5 mm;
— total analysis time: 23,00 mm;
— detector: 250 °C.BS ISO 16632 pdf download.