Zinc (Total) in Beer Worts

Photometric determination subsequent to acid mineralisation with sulfuric acid and Perhydrol®

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. 114566  Spectroquant® Zinc Cell Test
Cat.No. 100861  Spectroquant® Zinc Cell Test
Cat.No. 114832  Spectroquant® Zinc Test*
Cat.No. 100731  Sulfuric acid 95 - 97 % for analysis
Cat.No. 107209  Hydrogen peroxide 30 % (Perhydrol®) for analysis
Cat.No. 105590  Sodium hydroxide solution 32 % for analysis
Cat.No. 109535  MQuant® Universal indicator strips pH 0 - 14
Cat.No. 116754  Water for analysis
*not compatible with Move 100
Sample preparation:
In a 400-ml glass beaker mix 25 ml of wort with 2 ml sulfuric acid 95 - 97 % and 5 ml Perhydrol® for analysis and evaporate to a moist residue on the steambath. Dissolve again the residue into 5-ml Perhydrol® and reevaporate. The resultant oily fluid should be clear and colorless - if not, treat it once again with 5-ml Perhydrol® and, again, evaporate.
Take up the final residue into 15-ml of water for analysis and adjust by dropwise addition of sodium hydroxide solution 32 % to pH 5 - 8. Check by using Universal indicator strips. Transfer to a 25-ml volumetric flask and fill up to volume with water for analysis.
Determine with the above mentioned test kits
Zinc (total) content in mg/l Zn = analysis value in mg/l Zn