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BS ISO 4939:2016 pdf free

BS ISO 4939:2016 pdf free.Steel一Determination of nickel一Dimethylglyoxime spectrophotometric method
Evaporate until white fumes of perchloric acid appear and continue fuming at a temperature suitable to maintain a steady reflux of perchloric acid fumes on the walls of the beaker for at least 3 min and until any chromium is oxidized to chromate. Remove from the source of heat and allow to cool.
Add 50 ml of water, heat to dissolve salts, cool and transfer quantitatively to a 250 ml one-mark volumetric flask. Dilute to the mark with water and mix.
Filter by decantation through a dry filter to remove any residue or precipitate and collect the filtrate in a dry beaker, discarding the first fractions of the filtrate.
Transfer a 25 ml aliquot portion of the test solution (7.3.1) to a 100 ml one-mark volumetric flask.
If the test solution (7.3.1) contains cobalt, copper or manganese, the aliquot portion taken should be such that the respective contents of these elements do not exceed the following limits: cobalt, 5 mg;copper, 0,5 mg; manganese, 1 mg.
Add 20 ml of the ammonium citrate solution (4.3), mix, then add 3 ml of the iodine solution (4.4) and mix again. Allow to stand for 5 min.
Add 20 ml of the dimethylglyoxime solution (4.5), dilute to the mark with water and mix.
Allow to stand for at least 10 min and at most 20 min at a temperature of 20°C±5 °C.
Carry out the spectrophotometric measurement of the test solution at a wavelength of about 535 nm in a cell of appropriate optical path length (1 cm or 4 cm) after having adjusted the spectrophotometer (Clause 5) to zero absorbance with the corresponding compensating solution (7.3.3).
Introduce into a series of 250 ml beakers containing 10 ml of the acid mixture (4.1) and 10 ml of perchloric acid (4.2), the volumes of the nickel standard solution (4.7) indicated in Table 1, as appropriate for the expected nickel content.
Treat as described in 7.3.1 and 7.3.2, using the calibration solution“0″ as the compensating solution.BS ISO 4939 pdf free.

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