0.01 M Sodium Tetraphenylborate Preparation and Standardization

Preparation and Standardization of 0.01 M Sodium Tetraphenylborate (C6H5)4BNa) solution and calculating formula in Pharmaceutical labs.

Name: 0.01 M Sodium Tetraphenylborate (C6H5)4BNa)

Reagents: Sodium Tetraphenylborate
Sodium Hydroxide
Aluminium Hydroxide
Sodium Chloride
Cetylpyridinium Chloride
Potassium Chloride

0.01 M Sodium Tetraphenylborate Preparation and Standardization

Method of Preparation:

  • First, mix 3.5 grams of sodium tetraphenylborate in 50 ml of water.
  • Shake this with 0.5 grams of Aluminium hydroxide gel for about 20 minutes.
  • Then, add 250 ml more water and 16.6 grams of sodium chloride.
  • Let it sit for 30 minutes. After that, filter it. Add 600 ml of water and make sure the pH is between 8.0 to 9.0 using 0.1 M sodium hydroxide.
  • Finally, dilute it to 1000 ml with water.

Method of Standardization:

  • Before using, check its exact concentration in this way:
  • Dissolve 7 mg of potassium chloride (previously dried at 150°C for 1 hour) in 5 ml of acetate buffer pH 3.7 and 5 ml of water.
  • Add 15 ml of the sodium tetraphenylborate solution and let it stand for 5 minutes.
  • Then filter it through a dry, sintered glass filter.
  • To 20 ml of the filtrate, add 0.5 ml of bromophenol blue solution.
  • Titrate the excess sodium tetraphenylborate with 0.005M cetylpyridinium chloride till the indicator turns blue.
  • Repeat this without using potassium chloride.


The calculation formula is :

Where ‘a’ is the volume of 0.005 M cetylpyridinium chloride required without potassium chloride, ‘b’ is the volume required with potassium chloride, and ‘w’ is the weight of potassium chloride taken in grams.

Reference: This method is from the Indian Pharmacopoeia.

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