THE DETERMINATION OF CALCIUM IN BEER

The concentration of calcium is determined directly by using the technique of standard addition.

Equipment Required:

1. Ion analyzer (recommended) or pH meter with millivolt scale.
2. detectION 3041 calcium ion selective electrode

Reagents:

1. Calcium standard solution O.1m CaCl₂: Dissolve 11.1g of Calcium Chloride into distilled water in a volumetric flask and dilute to 1000 ml.
2. Sodium hydroxide solution 1.0m NaOH: Dissolve 40g of NaOH into distilled water in a volumetric flask and dilute to 1000 ml.

Sample Preparation:

Take 150 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.

Method:

Place electrode into 100 ml of prepared sample, stirring thoroughly. Record the electrode potential mV₁. Add 1.0 ml of O.1m CaCI₂ standard to the sample solution, stirring thoroughly and allow the reading to stabilize. Record the new electrode potential, mV₂.

Calculation:

Use the equation for standard addition. Appendix 1 Section 5. The     E value will be given by mV₂ – mV₁. The slope of the electrode should be +29mV. This can be checked by running a calibration curve of 3 known CaCl₂ solution concentration.