1) Solvent extraction is a technique used to separate components in a mixture based on differences in solubility between two immiscible liquid phases. 2) It involves transferring a solute from one liquid phase to another, such as transferring a compound from an aqueous phase to an organic phase like benzene. 3) The amount of solute extracted into each phase can be calculated using the partition coefficient K, which is a ratio of concentrations in the two phases at equilibrium.

1. Solvent Extraction
“Real” samples are complex
Many components, many interferents
mixture separation

2. What to do:
a. Masking agents
b. Precipitation and Filtration
c. Distillation
d. Extraction
e. Chromatography

4. Solvent Extraction
Isolate individual components based on differences
in solubility, pH…
Transfer a solute from one phase to another
Phase 1 (benzene)
Phase 2 (water)
Aaq = Aorg
Activity (A) org
Activity (A) aq
K =
Partition
Coeff

5. To calculate how much is in each phase,
K
Volume of organic phase
Volume of aqueous phase
Initial concentration in aqueous phase
n
orgaq
aq
KVV
V
q )(
+
=
[ ] ( ) [ ]A
V
V V K
Aaq n
aq
aq org
n
aq=
+
0
n = # times

8. Much better to use a large # of small portions
of solvent, rather than one large one
Fraction
remaining
# extractions

9. It is desired to extract 80.0% of the amylacetate from a
banana peel in one extraction. If K is 10 and the volume
of water the banana peel is homogenized in is 50.0 mL,
how many mL of organic solvent will be required.
a. 1.25
b. 20
c. 50
d. 65
Clicker question:

10. It is desired to extract 80.0% of the amylacetate from a
banana peel in one extraction. If K is 10 and the volume
of water the banana peel is homogenized in is 50.0 mL,
how many mL of organic solvent will be required.
a. 1.25
b. 20
c. 50
d. 65
Clicker question: