2.6. Extraction with DCM
Extraction with DCM resulted in the formation of a large
amount of coagulum (or white precipitate) in the majority
of the bull urine, making extraction difficult. In contrast,
however, scanty white precipitate appeared while
extracting buffalo cow urine samples using DCM.
To avoid this coagulum, the final solvent phase of all the
sampleswas further filtered withWhatman no.1 filter paper,
and only clear solvent phase was collected in the glass vials.
These vials, containing w50 mL of the solvent phase were
subjected to evaporation under a vacuum oven (Metzer,
Metzer Opto-Electronic Inst. Pvt. Ltd.) at room temperature.
The evaporation was stopped, when w2 mL of solvent was
left at the bottom of the vials. These vials were then tightly
screwed and stored in a refrigerator until GC-MS analysis.