Analytical Method: Nickel (total) in electrophoretic paints

Instruments and Reagents:

Cat.No. 173016  Spectroquant® VIS Spectrophotometer Prove 100 or

Cat.No. 173017  Spectroquant® UV/VIS Spectrophotometer Prove 300 or

Cat.No. 173018  Spectroquant® UV/VIS Spectrophotometer Prove 600 or

Cat.No. 109748  Spectroquant® Photometer NOVA 30 or

Cat.No. 109751  Spectroquant® Photometer NOVA 60 or

Cat.No. 173632  Spectroquant® Colorimeter Move 100

Cat.No. 114946  Rectangular cells 10 mm and/or

Cat.No. 114947  Rectangular cells 20 mm and/or

Cat.No. 114944  Rectangular cells 50 mm
Cat.No. 114554  Spectroquant® Nickel Cell Test
Cat.No. 114785  Spectroquant® Nickel Test
Cat.No. 100731  Sulfuric acid 95 - 97 % for analysis
Cat.No. 107210  Hydrogen peroxide 30 % (Perhydrol®) for analysis
Cat.No. 105590  Sodium hydroxide solution 32 %
Cat.No. 109535  MColorpHastTM Universal indicator strips pH 0 - 14
Cat.No. 116754  Water for analysis
Sample preparation:
In a 400-ml glass beaker add 10 ml homogenized paint sample to 10 ml of sulfuric acid 95 - 97 % for analysis, swirling to mix. For complete solubilisation of the sedimented resins, heat the mixture on the steambath to
100 °C. After addition of 2 ml Perhydrol®, the dark-brown solution is decolorized. When foaming has subsided, add once more 2 ml of Perhydrol®, followed by a slow and cautious warming. After this add further 2 ml Perhydrol® and heat to boiling (glass beads, as anti-bump medium).
If the mixture remains clear and colorless after 10 minutes heating, allow to cool to room temperature. Should the color remain brown, repeat the treatment with 2 ml Perhydrol® with a further 10 minutes heating.
Dilute the cooled solution to 100 ml with water for analysis and adjust the pH (pH-meter) to 4, using sodium hydroxide solution 32 % and transfer to a 200-ml standard volumetric flask. Fill up to volume with water for analysis and mix well.
Determine with the above mentioned test kits.
Using the 1+99 sample dilution the analysis value corresponds directly to the nickel (total) content in mg/l.


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