Chloride is extracted from the meat directly into an Ionic Strength Adjustment Buffer.
Equipment Required:
- Corning pH/Ion Analyzer OR Corning pH Meter with mill volt scale
- Corning Chloride I.S.E.
- Corning Double junction Reference electrode.
- Reference electrode lead.
Reagents:
Ionic Strength Adjustment Buffer (ISAB):
This should be 0.5M Nitric Acid (ie. 31.25 ml Conc. HNO2/1) Chloride Stock Solution (O.1M):
Dissolve 5.85g of Sodium Chloride (dried for 1 hour at 600° C) in distilled water in a volumetric flask and dilute to 1000ml. Reference Electrode Filling Solution (1M KNO2):
Standard Preparation:
Make up standards of 0.01M; 0.001M and 0.0001M by dilution of the 0.1M chloride standard in distilled water. Dilute these standards 1:1 with the ISAB.
Sample Preparation:
Prepare the sample by taking 1g of meat and liquidising with 100ml of distilled water. Centrifuge the mixture and to 20ml of the supernatant add 20 ml of ISAB.
Method:
Immerse the electrodes in each of the prepared standards in increasing concentration steps, rinsing the electrodes in distilled water between standards.
Plot a graph of mV response against standard concentration on lin/log graph paper.
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. Calculations:
To calculate the chloride concentration of the original sample multiply the result obtained from the graph (M130) or direct from the display (M135) by 100.