Calcium is extracted from the meat directly into an Ionic Strength Adjustment Buffer.
- Ion Analyzer (recommended) or pH meter with millivolt scale
- detectION 3041 calcium ISE
Ionic Strength Adjustment Buffer (ISAB) - This should be 0.1M Potassium Chloride (dissolve 7.45g of KCl in 1000ml distilled water). Calcium Stock Solution (0.1M) - Dissolve 11.1g of Calcium Chloride in distilled water in a volumetric flask and dilute to 1000ml. Reference Electrode Filling Solution (0.1M KNO3) - Dissolve 10.1g of Potassium Nitrate in distilled water in a volumetric flask and dilute to 1000ml.
Make up standards of 0.01M, 0.001M and 0.0001M by dilution of the 0.1M calcium standard in distilled water. Dilute these standards 1:1 with the ISAB.
Prepare the sample by taking 1 g of meat and liquidizing with 100ml of distilled water. Centrifuge the mixture and to 20ml of the supernatant add 20ml of ISAB.
Immerse the electrode in each of the prepared standards in increasing
concentration steps, rinsing the electrodes in distilled water between
Plot a graph of mV response against standard concentration on semilog graph
Immerse the electrodes in the sample solution; record the mV response and plot
sample concentration from the graph.
Using the Model 135, this determination may be carried out directly in
concentration units, using the "Activity" modes.
To calculate the calcium concentration of the original sample multiply the result obtained from the graph (M130) or direct from the display (M135) by 100.