PURPOSE
To lay down the procedure for Clarity of the solution.
APPARATUS
Analytical balance
Nessler’s cylinders
Volumetric flasks – 100 ml & 1000 ml
Graduated pipettes – 25.0 ml
Bulb pipettes – 5.0, 10.0, 20.0, 25.0 ml & 50.0 ml
REAGENTS
Hydrazine sulfate: AR grade
Hexamine: AR grade
Freshly distilled water
PROCEDURE
Standard of opalescence:
- Transfer about 1.0 g of accurately weighed hydrazine sulfate into a 100.0 ml volumetric flask and make up to volume with water. Allow it to stand for 4 to 6 hrs.
- Add 25.0 ml of this solution to a solution containing 2.5 g of hexamine in 25.0 ml of water.
- Mix well and allow to stand for 24 hours.
- This suspension is stable for 2 months provided that it is stored in a glass container free from surface defects.
- Dilute 15.0 ml of the suspension to 1000 ml with water. This is the standard of opalescence and must be used within 24 hrs.
- Reference suspensions – Reference suspensions I to IV are prepared as Table-I. Each suspension is to be mixed and shaken before use.
| I | II | III | IV |
Standard of opalescence (ml) | 5.0 | 10.0 | 30.0 | 50.0 |
Water (ml) | 95.0 | 90.0 | 70.0 | 50.0 |
- Prepare a minimum of 50 ml sample solution as specified.
- Into separate Nessler’s cylinders place a sufficient amount of sample solution being examined and the appropriate reference suspension, such that the cylinders are filled to a depth of not less than 40 mm.
- Five minutes after the preparation of the reference suspension, compare the contents of the Nessler’s cylinders against a black background by viewing in diffused daylight down the vertical axes of the tubes. The diffusion of the light must be such that the reference suspension I can be readily distinguished from water and from reference suspension II.
- A liquid is considered clear if its clarity is the same as that of water or of the solvent used for making the solution or if its opalescence is not more pronounced than that of reference suspension I (given in Table-I).
- The degree of opalescence is expressed in terms of reference suspensions
REFERENCE
BP
USP
Tags
GTP
