A cloudy solution was formed in
the test tube(the cloudy state was stable for a long time).This
cloudy state resulted from the dispersion of fine particles of
benzophenone in the bulk aqueous sample. Then,the mixture
was centrifuged at 4000 rpm for 5 min.Accordingly,the dispersed
fine particles of benzophenone were sedimented in the bottom of
the conical test tube.The aqueous phase was then separated
completely by a syringe.Later,these dimented phase was dissolved and made up to 1.0 mL by adding ethanol.The resultant
solution was introduced into the flame by conventional aspiration.
The extraction steps are illustrated in Fig. 1.