CHML212
Exp. 24 Synthesis and GC Analysis of FAMEs
IN-LAB ASSIGNMENT: (EACH STUDENT will record the following data in his/her laboratory notebook in a well organized
manner during lab period. Yellow carbon copies will be submitted for grading along with Post-Lab assignment.) …..max
score = 20 pts.
6. Data/Calculations
a.
b.
c.
d.
e.
f.
Unknown used
TLC diagram with all cm measurements
TLC solvent system used
TLC detection method used
GC vial slot number
All adjusted area % calculations
7. In-lab Question (The following question should be answered in laboratory notebook.)
a. Draw the structures of the 3 fatty acid methyl esters which would result from the following
transesterification:
A.
B.
CH2O
C.
D.
CHO
E.
F.
CH2O
G.
O
C
CH2(CH2)4CH3
O
C CH2(CH2)8CH3
O
C
CH2(CH2)6CH3
KOH
CH3OH
CHML212
Exp. 24 Synthesis and GC Analysis of FAMEs POST-LAB ASSIGNMENT: (EACH LAB GROUP will submit one copy of a
typewritten, paragraph style report addressing all of the points listed below. Must be written using PAST TENSE,
PASSIVE VOICE. ) …..max score = 50 pts.
8. Experimental (Write 1-2 paragraphs including all of the following. Do NOT present a bulleted outline.)




What type of reaction did you perform?
Describe the actual synthetic procedure. Include names of any reactants used and desired product, as well as
name of solvent and catalyst used (if any). Be sure to give actual names and volumes/masses of compounds used
during the synthesis (not just what the lab manual tells you to use).
Describe the purification technique used to isolate the desired product, including actual names and volume/mass
of any compounds used during purification process.
Describe the analytical technique used to evaluate the product, including actual names and volume/mass of any
compounds used during sample preparation and analysis.
9. Results (Cut and paste completed tables into your document.)
Table 24.1 TLC results
TLC Diagram
(Show measurements for all
spots and solvent front in cm)
Compound
Table 24.2 GC results
GC Retention Times (min)
Standard
Sample
Area
Percent
Adjusted
Area Percent
Pentane
Methyl Palmitate
Methyl Linolate
Methyl Oleate
Methyl Stearate
Fatty
Acid
Type
% SFA
% MUFA
% PUFA
Table 24.3 Expected vs. Experimental Results
Expected
Experimental
Relative Fatty Acid
FAMEs
Composition
Composition
Proposed
Oil
Identity
10. Discussion (Write 1-2 paragraphs including the following.)




List the identity and adjusted area percent values of all FAMEs in the unknown sample. How do the calculated
percent composition values compare to the expected values based on the relative fatty acid composition of
common oils? What is the proposed identity of the unknown oil?
In what order did the FAMEs elute from the GC column? Does the order of elution of the compounds make sense
based on the size and unsaturation of the fatty acids and their corresponding FAMEs? Briefly explain.
Include a short comment addressing what could be done differently to improve the experimental results, if
repeated.
Be sure to attach GC sample chromatogram!