The Determination Of Calcium in Beer

The concentration of Calcium in Beer is determined directly by using the technique of standard addition.

 

Equipment Required

1.  Model QP459 Ion Meter

2.   3041 Calcium Combination ISE

3.   21310 Calcium 1000ppm Standard Solution

4.   Glassware: Beakers 250ml; Volumetric Flask 100ml; 10ml pipette. 

5    Sodium hydroxide solution 1.0m NaOH

6.   Deionised water

 

 
An image showing a portable ion meter.
Image showing a bottle of 500ml Standard Solution.

Sample Preparation:

Take 100 ml of beer sample and pass through filter paper to equilibrate CO2 content with air.

Adjust the pH of the sample to 5.5 – 6.0 pH with 1.0m NaOH if necessary.  Prepare the Sodium hydroxide solution by dissolving  40g of NaOH into distilled water in a volumetric flask and dilute to 1000 mls.

 

Method

Place the  3041 Calcium Combination ISE into 100 ml of prepared  beer sample, stirring thoroughly.

Record the electrode potential E1. Add 1.0 ml of  21310 Calcium 1000ppm Standard Solution  to

the sample solution, stirring thoroughly and allow the reading to stabilise. Record the new electrode 

potential, E2..

Calculation:

Use the following equation for standard addition.

Cu = Cs x [Vs/(Vu + Vs)] / [(10{(E2-E1)/ˢ}) – (Vu/(Vu + Vs))]

 

Where: Cu = Concentration of the sample.

Cs = Concentration of the standard.

Vs = volume of the standard.

Vu = volume of the sample

E1 = Electrode potential (mV) of the Sample.

E2 = Electrode potential after the Standard addition.

ˢ  = the electrode slope.

 

The perfect slope of the electrode should be +29mV. This can be checked by running a calibration curve of 3 known CaCl2 solution concentration. +27mV is more likely.