CHML211
Exp. 6 Extraction of Analgesics
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 (The following information should be recorded directly into laboratory notebook.)
a.
b.
c.
d.
EXTRACTION:
i. Theoretical recovery CALCULATION for aspirin (not just the value!)
ii. Theoretical recovery CALCULATION for acetaminophen (not just the value!)
DRYING AND ACETAMINOPHEN RECOVERY:
i. Mass of 150 mL beaker
ii. Mass of 150 mL beaker+ acetaminophen
iii. Final recovered mass of acetaminophen
iv. Percent recovery CALCULATION for acetaminophen (not just the value!)
ASPIRIN RECOVERY:
i. Mass of small filter paper
ii. Mass of large filter paper
iii. Mass of filter papers + dried aspirin
iv. Final recovered mass of dried aspirin
v. Percent recovery CALCULATION for aspirin (not just the value!)
vi. Experimental melting point of aspirin
HPLC ANALYSIS:
i. HPLC vial slot # for aspirin sample
ii. HPLC vial slot # for acetaminophen sample
7. In-lab Questions (The following questions should be answered in laboratory notebook.)
a.
Draw a complete mechanism for the reaction which occurs between aspirin and 10% NaHCO3 using actual
chemical structures and mechanism arrows to indicate electron flow.
O
O
H
H3C
O
O
+
Na
O
OH
O
b.
Draw a complete mechanism for the reaction which occurs between acetaminophen and 10% NaOH using
actual chemical structures and mechanism arrows to indicate electron flow.
O
H
N
CH3
+ Na
OH
O
H
CHML211
Exp. 6 Extraction of Analgesics
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.)




Describe the acid-base extraction technique used, including specific names and volumes/masses of any
compounds used during purification.
Describe the process of recovering the acetaminophen, including:
o Drying the organic layer
o Performing the suction filtration, and why it was used
o Any masses or volumes obtained during this step, and names of any compounds used
o How the solvent was removed from the acetaminophen
o Preparation of HPLC sample—how much sample was used, which solvent was used to prepare the
sample, and which HPLC vial slot # was used
o How the product was secured
Describe the process of recovering the aspirin, including:
o Acidification of aqueous layer and pH testing
o Performing the suction filtration, and why it was used
o Any masses or volumes obtained during this step, and names of any compounds used
o Preparation of HPLC sample—how much sample was used, which solvent was used to prepare the
sample, and which HPLC vial slot # was used
o How the product was secured
Describe the process of identifying and quantifying the compounds using HPLC analysis
9. Results (Copy and paste the completed tables into your document.)
Table 6.1 Experimental results
Aspirin
Acetaminophen
Theoretical recovery after extraction (g)
Actual recovery after extraction (g)
% Recovery after extraction
Compound
Table 6.2 HPLC results
HPLC retention times (min) and area %
Aspirin
Acetaminophen
Standards
Sample
Sample
Rt
Rt
area %
Rt
area %
(min)
(min)
(min)
Aspirin
Acetaminophen
10. Discussion (Write 1-2 paragraphs including the following.)






What was the percent recovery of the aspirin after the extraction technique? What was the percent recovery of
acetaminophen after the extraction technique? Give actual numerical values.
Based on HPLC analysis of the aspirin sample, is there any indication of acetaminophen present? Give the name
and area % of any compound in this sample chromatogram.
Based on HPLC analysis of the acetaminophen sample, is there any indication of aspirin present? Give the name
and area % of any compound in this sample chromatogram.
Based on the statement above, was pure aspirin isolated? And pure acetaminophen? Briefly explain.
Include a short comment addressing what could be done differently to improve the experimental results, if
repeated.
Be sure to attach your HPLC sample chromatograms to your final lab report!