Method To Test Emulsion Strength Of a Formulated EC

It is very very important for a formulator to select right emulsifier and introduction of right dosage in a formulation because the marketed formulation must perform perfectly throughout its shelf life bearing all the climatic conditions and perform while it is subjected for the application at the farmer level at unknown temperature and unknown water hardness at any point of time.

To satisfy the above mentioned criteria, if an EC formulation can perform best in 34. 2ppm hard water to 800ppm hard water, it can also sustain all the variations of the climatic conditions.

Therefore the formulation chemist have to keep the dosage level of emulsifier in any formulation in such a way that the formulation should perform the best in the hardness ranging from 34.2ppm to 800ppm water hardness.

Only right emulsifier, right ratio optimization and right dosage can satisfy all the parameters, therefore through our research, knowledge and experience, we can share the determination of right emulsifier, right ratio optimization and right dosage which are explained here under.

In general the nature of the toxicant and type of solvents used would influence the selection of emulsifiers. Furthermore, the choice of the ratio and the total dosage of emulsifiers may vary from one formulator to another, depending upon the sources of raw materials and the emulsion standards aimed at. Therefore, we recommend that the appropriate ratio and total dosage are identified (screening) by the formulator using representative samples of the inputs such as the toxicants and solvent.

Check the emulsion stability of the formulated material in 34.2 ppm (Soft Water), 342 ppm (Standard Hard water) and 800 ppm for 1½ hrs as per BIS / WHO / CIPAC testing method in 100 ml emulsion tubes as shown in the picture below:

Picture 7

From that a formulation chemist can easily find out:

  • Quality status of any formulated material, whether the sample is drawn from their previous batches formulated with the other suppliers’ emulsifier or sample drawn from the market.

  • Selection of the right emulsifier & right dosage.

  • Whether the formulated material can satisfy all international standards or not.

  • Whether his formulated material can sustain its performance against all water hardness & temperatures or not  at the user end  by simple method mentioned as under:

First of all we need to prepare 34.2ppm, 342ppm & 800ppm hard water. Although, all the formulation chemists are aware of method of preparation of above mentioned standard hard waters, we feel our duty to mention here as follows.

Method of Preparation of Hard Waters:-

  • 342 ppm Hard Water:-
    Take CaCl2– 0.304 gms, MgCl2-0.139 gms dilute up to 1 litre using distilled water.

  • 34.2ppm Hard Water:-
    Take 100ml of 342ppm water dilute up to 1 litre using distilled water.

  • 800ppm Hard Water:-
    Take CaCl2– 0.7111 gms, MgCl2-0.3252 gms dilute up to 1 litre using distilled water.

Please note use dehydrated CaCl2 and MgCl2 (GR Grade)

SPONTANEITY:  Spontaneity is the criteria for testing self-emulsifiability and dispersibility of the emulsifiable concentrate without external aid, such as stirring etc. When a drop of emulsifiable concentrate (sp. Gr > 1) is added in 3 different test tubes / cylinders each containing 100ml. of 34.2, 342, 800 ppm hard water respectively, it should show immediate bloom or it should flourish in the form of white emulsion forming cloud made of very small emulsified particles where it bloomed.

When a drop of emulsifiable concentrate (Sp. Gr<1) is added to aforesaid range of hard waters, it should immediately emulsify on the surface of water without showing aggregation of emulsified particles or part emulsification.

The above test also gives the judgement for the optimisation of the Anionic & Non-ionic combinations and to ascertain the dosage of Emulsifier required for any formulation. At the same time it is an effective method to judge the quality of Emulsifier supplied by any supplier.

WHITENESS: When one drop of EC is added in 3 different test tubes, first test tube/emulsion tubes containing 34.2 ppm, Second test tube/emulsion tube containing 342ppm and third test tube/emulsion tube containing 800ppm hard water respectively, it should show good and almost equal whiteness in all the three aforesaid range of hard water. More whiteness will enhance thickness of emulsion.

If the subjected sample of formulation satisfy the above mentioned test (showing dense emulsion in all the hard waters or show bluish emulsion in 342ppm hard water) then you can be confident that the subjected formulation can withstand against all the probable water hardness and temperatures, found at the user end.

Take 2 ml or 5ml of the same formulated solution and check the same in all the hardness as per the method prescribed by BIS, CIPAC, WHO standard specifications in 100ml capacity emulsion tubes and keep it for 1½ hr. for observation. If observed no creaming/oil separation/phase seperation at the top or no sediment/oil separation at the bottom in all the hard waters then the dosage of emulsifier used in the subjected formulated material is correct.

To know or compare the formulation or emulsifiers strength, the formulation chemist must do the above mentioned test.