General Test Procedure Clarity of Solution

Purpose
1. This procedure is applicable to all incoming Raw materials.
Apparatus
1. Test tubes
Reagents
1. Hydrazine Sulphate
2. Hexamine
3. Purified water
Procedure
1. Into separate matched, flat-bottomed test tubes, 15 to 25 mm in internal diameter and of colorless, transparent, neutral glass, place sufficient quantity of the solution being examined and the appropriate reference suspension, freshly prepared as specified below, such that the test tubes are filled to a depth of 40 mm.
2. Compare the contents of the test tubes against a black background by viewing in diffused daylight down the vertical axes of the tubes 5 minutes after preparation of the reference suspension.
3. The diffusion of the light must be such that reference suspension I can be readily distinguished from water and from reference suspension II.
4. Standard of opalescence: Dissolve 1.0 g of hydrazine sulphate in sufficient water to produce 100 ml and allow standing for 4 to 6 hours.
5. Add 25 ml of this solution to a solution containing 2.5 g of hexamine in 25 ml of water mix well and allow standing for 24 hours.
6. This suspension is stable for 2 months provided that it is stored in a glass container free from surface defects.
7. The suspension must not adhere to the glass and must be well mixed before use.
8. To prepare the standard of opalescence, dilute 15 ml of the suspension to 1000 ml with water. This suspension must be used within 24 hours of preparation.
9. Reference suspensions: Reference suspensions I to IV are prepared as indicated in the table. Each suspension is to be mixed and shaken before use.

Reference suspensions	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

1. Expression of clarity and degree of opalescence.
2. A liquid is considered clear if its clarity is the same as that of water or of the solvent used when examined under the conditions described above or if its opalescence is not more pronounced than that of reference suspension I.
3. Requirements for degree of opalescence are expressed in terms of reference suspensions I, II, III and IV.
Reference
1. None
Revision History