Calcium in Beer

Photometric determination with phthalein derivative

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. 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. 100049  Spectroquant® Calcium Test
Cat.No. 116754  Water for analysis

Sample preparation:
Fill 100 ml of beer in a 600 ml beaker. Stir in order to drive off the CO2 for about 1 hour with a magnetic stirrer. Alternatively you can use also an ultra sonic bath. Attention! Foams strongly.
Dilution steps:
Samples containing higher than 4.00 mg/l Ca must be diluted with water for analysis according to the following table:

Expected original
beer concentration
volume of
Filling up in a volumetric
flask with x ml volume
25 mg/l 8 ml 100 12.5
50 mg/l 4 ml 100 25
100 mg/l 2 ml 100 50
200 mg/l 1 ml 100 100

Therefore pipette x ml of this solution into a 100-ml volumetric flask and fill up to volume with water for analysis to the mark
(= diluted beer sample).

Determine the CA content with the above mentioned test kit against a reagent blank (water for analysis (instead of beer) + reagents).

The method is preprogrammed on the Prove instruments, but has to be calibrated for each batch.
For details see Prove manual.
It is recommended to perform a calibration with 5 - 10 measurement points over the entire measuring range.
The calibration should be checked regulary using standard solutions.