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.

Beer Glass

Dilution steps:
Samples containing higher than 4.00 mg/l Ca must be diluted with water for analysis according to the following table:

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).

Analysis:
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.

Materials
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