This method requires:
  • Adapted equipment: (burette, magnetic stirrer, magnetic stir bar, reagents prepared according to the European pharmacopoeia standards, graduated pipettes).
  • Adapted personal and collective protective equipment (laboratory coat, glasses).
Equipment and reagents:
  • Burette
  • Magnetic stirrer
  • 100 mL Erlenmeyer
  • Weighing cup
  • Titrated sodium hydroxide solution Na(OH)
  • Magnetic stir bar
Dissolve approximately 70 mg lidocaine hydrochloride precisely weighed in 40-50 mL of 95% ethanol in the presence of the bar magnet. Place the electrode in the solution and then stir moderately. Carefully add the tittered sodium hydroxide solution 0.5 mL at a time. After each addition, note down the potential given by the potentiometer. When the readings indicate that the inflection point is close, add 0.2 mL at a time so as not to miss the equivalence point. When the values indicate that a plateau is about to be reached, add in 0.5 mL increments until this plateau is reached.

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