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Analytical Method: Chromium (total) in building materials

Instrumenst 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. 114552  Spectroquant® Chromium Cell Test
Cat.No. 114758  Spectroquant® Chromium Test
Cat.No. 104885  Potassium hydrogen sulfate for analysis
Cat.No. 109535  MColorpHastTM Universal Indicator strips, pH 0 - 14
Cat.No. 116754  Water for analysis
 
Note:
Differential analysis of chromate soluble in hot water and total chromium can be carried out with suitable sample preparation.
 
Sample preparation - hot water extraction:
Prepare a fine powder of the sample and dry at 105 °C. Mix 5 g with water for analysis and boil for 30 minutes on a hot plate. Allow to cool, transfer the suspension to a 200-ml volumetric flask and make up to the mark with water for analysis. Mix well, filter through a paper filter and use the filtrate as sample for the determination of water - soluble chromate.
 
Sample preparation - total content:
Place 200 mg of the finely powdered material along with 5 g potassium hydrogen sulfate in a DURAN test tube, mix and heat gently in a bunsen flame until a clear orange - colored melt is obtained and no more gas is given off. Allow to cool, add water for analysis to dissolve most the residue and transfer the suspension to a 100-ml volumetric flask. Make up to the mark with water for analysis and mix well.
Filter through a paper filter and adjust the pH to 1 - 8.
 
Analysis:
Determine with the above mentioned test kits.
 
Calculation:
Chromate content (water-soluble) in % CrO4 = analysis value in mg/l CrO4 x 0.004
Chromium total content in % Cr = analysis value in mg/l Cr x 0.05

Materials

     
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