Abstract

Sodium acetate is widely used in chemical and medical industry (E.g. Buffer, Antifreezing agent, Alkalizing supplements, Dye chemical, Hydragogue). Determination method of sodium acetate is described on Japanese Pharmacopoeia and Japanese Industrial Standard (JIS K8371). Both methods employ perchloric acid titration method, dissolve the sample in glacial acetic acid and titrate with perchloric acid – acetic acid standard solution. Endpoint is detected by potentiometric titration with glass / reference electrodes.

CH3COONa ＋ HClO4 → CH3COOH ＋ NaClO4

Configuration of instruments and Reagents

• Instruments
  • Main unit : Hiranuma Automatic Titrator COM Series
  • Electrode : Glass electrode GE-101B Reference electrode
    • RE-201Z
    • (Inner solution should be changed; it is described below)
• Reagents
  • Titrant : 0.1 mol/L perchloric acid in glacial acetic acid standard solution
  • Titration solvent : Glacial acetic acid
  • Electrolyte : Saturated sodium perchlorate in glacial acetic acid
    • (For inner solution of reference electrode)

Measurement procedure

1. Take 0.2 g of the sample into a 100 mL tall-beaker and accurately weigh it.
2. Add 50 mL of acetic acid and dissolve the sample.
3. Immerse the electrodes and start titration with 0.1 mol/L perchloric acid in glacial acetic acid standard solution. Perform blank test without sample.

Measurement Conditions and Results

Example of titration condition

Note