Four tests are used to identify oil-in-water (O/W) and water-in-oil (W/O) emulsions: the dilution test, dye test, conductivity test, and fluorescence test. The dilution test identifies the emulsion type based on whether it dilutes easily with water or oil. The dye test observes emulsion droplets under a microscope after adding an oil-soluble dye. If the continuous phase is colored and droplets are clear, it is a W/O emulsion; if droplets are colored and the continuous phase is clear, it is an O/W emulsion. The conductivity test uses electrodes - if a bulb glows, it is an O/W emulsion, and if not, it is a

1. Test For
Identification of
Type of Emulsion
Prepared By:
Lect. Mr. S. S. Mistree
Sub:-Pharmaceutic’s-II
Ishwar Deshmukh Institute of Pharmacy, Digras
Yavatmal-445203
2019-20

2. The following test are done to discriminate between O/W
and W/O emulsion
1. Dilution Test
2. Dye Test
3. Conductivity Test
4. Fluorescence Test

3. Dilution Test:
 The emulsion can identify on the basis of dilution test
Emulsion is diluted with water/oil
O/W emulsion easily diluted with water
W/O emulsion easily diluted with oil

4.  Dye Test:
 when an emulsion is mixed with a oil soluble dye such as scarlet
red dye and observed under the microscope.
 If the continuous phase shows red color and dispersed globules
shows colorless means W/O type of emulsion
 If the dispersed globules shows red color and continuous phase
colorless, means O/W type of emulsion

5. Conductivity Test:
Water is good conductor of electricity but oil is not
This test perform by dipping pair of electrode connected by a bulb in
the emulsion
If the bulb glow that means O/W type of emulsion
If not glow that means W/O type of emulsion

6. Fluorescence Test:
Certain fixed oil has property of fluorescing in presence of UV
radiation on microscopic observation.
If continuous phase give fluorescence that means W/O type of
emulsion.
If dispersed globules gives fluorescence that means O/W type of
emulsion.

7. Thank you…
References:
R. M. Mehta, pharmaceutics-II, third eddition-2010,vallabh
prakashan.