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ISO 9697:2015 pdf free

ISO 9697:2015 pdf free.Water quality一Gross beta activity in non-saline water
After dryingand ignition, some water residue can be hygroscopic or dficult to disperse, and thus, unsuitable for the activity measurement. A sulfation process is then a suitable treatment for such water samples.
Ensure that the rinses in the dish are cool and add (1±0,2) ml of sulfuric acid (5.1.4).
The volume of sulfuric acid chosen is sufficient for sulfating about 1,8 g of calcium carbonate. To ensure an excess of acid, the initial volume of sample should be chosen such that the total solids content does not exceed 1 g (experience with some waters can show this step to be unnecessary).
Carefully evaporate the contents of the dish to dryness.
To avoid spitting, heat the dish from above using an infrared lamp until fumes of sulfuric acid are evolved. Then, transfer the dishes to a hotplate untill no further fumes are evolved.
Transfer the dish and contents to the muffle furnace (5.2.3), ignite for 1 hat a temperature of(350±10)℃ and allow to cool to room temperature in a desiccator.
Weigh the dish and the residue and obtain by difference, m, in milligrams, the mass of the ignited residue.
If the residue is coarse, grind it in a pestle and mortar. Transfer the required mass of the residue onto a planchet (5.2.2). Let this mass be mr
If the volume of the sample used (V, in 6.3) has led to a value of ps less than 0,1 mg/mm-2, transfer as much as possible of the residue to the planchet.
Disperse the residue evenly over the planchet by slurrying with a few drops of a volatile organic solvent (5.1.5, methanol or acetone) and allow it to dry to a constant mass. It is also recommended that, to produce evenly spread counting sources, vinyl acetate (5.1.2) can be added to the solvent to aid in binding the source. Make a note of the time and date of source preparation, and check that no residue has been lost.
Although beta-particle counting efficiency is not seriously affected by the source thickness up to 0,2 mg mm-2 (see References[4] and [5]), it is recommended that, for the calibration of the detection system, either use standard sources of the same mass loading (mr) or repeat the procedure with the addition of calcium salts to the water sample to achieve the same mass loading as the calibration standard.ISO 9697 pdf download.

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