A2-5
APPENDIX 2
• Pump 2 - a burette filled with 1 M NaOH.
A2.3.3 Preparing the Sample
For this example commercial antacid pills were used.
• Crush several pills with a mortar and pestle. From the crushed pills weight roughly
0.5 g into a 150 mL sample beaker.
• Pour about 20 mL distilled and deionized water into the beaker.
• Raise the stirrer assembly.
• Place the beaker under the stirrer assembly.
• Lower the stirrer assembly until it rests on its positioning collar.
• Adjust the height of the stirrer so it is as close as possible to the bottom of the
beaker.
• If necessary add more distilled or deionized water so that the pH electrode bulb is
completely immersed in the sample and the reference junction of the electrode is 5-
6 mm below the surface.
A2.3.4 Perform the Titration
• When the method is selected (the main screen displays “Antacid Power”) press .
• The titrator will prompt for the sample weight. Enter the exact weight value (with 4
digits) and press .
• The calculated volume of titrant 1 is displayed (this value can be modified by the
user). The displayed volume will be dispensed during the first phase of back-titration.
• Press to proceed with the next step.
• The titrator will start to dispense titrant 1 (1 M HCl).
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