(Ph. Eur. monograph 0009)
AgNO3 169.9 7761-88-8
Action and use
Antiseptic.
Preparations
Silver Nitrate Eye Drops
Silver Nitrate Solution
Silver Nitrate Sterile Solution
DEFINITION
Content
99.0 per cent to 100.5 per cent.
CHARACTERS
Appearance
White or almost white, crystalline powder or transparent, colourless crystals.
Solubility
Very soluble in water, soluble in ethanol (96 per cent).
IDENTIFICATION
A. 10 mg gives the reaction of nitrates (2.3.1).
B. 10 mg gives the reaction of silver (2.3.1).
TESTS
Solution S
Dissolve 2.0 g in water R and dilute to 50 mL with the same solvent.
Appearance of solution
Solution S is clear (2.2.1) and colourless (2.2.2, Method II).
Acidity or alkalinity
To 2 mL of solution S add 0.1 mL of bromocresol green solution R. The solution is blue. To 2 mL of solution S add 0.1 mL of phenol red solution R. The solution is yellow.
Foreign salts
Maximum 0.3 per cent.
To 30 mL of solution S, add 7.5 mL of dilute hydrochloric acid R, shake vigorously, heat for 5 min on a water-bath and filter. Evaporate 20 mL of the filtrate to dryness on a water-bath and dry at 100-105 °C. The residue weighs a maximum of 2 mg.
Aluminium, lead, copper and bismuth
Dissolve 1.0 g in a mixture of 4 mL of concentrated ammonia R and 6 mL of water R. The solution is clear (2.2.1) and colourless (2.2.2, Method II).
ASSAY
Dissolve 0.300 g in 50 mL of water R, add 2 mL of dilute nitric acid R and 2 mL of ferric ammonium sulfate solution R2. Titrate with 0.1 M ammonium thiocyanate until a reddish-yellow colour is obtained.
1 mL of 0.1 M ammonium thiocyanate is equivalent to 16.99 mg of AgNO3.
STORAGE
In a non-metallic container, protected from light.
