David Millard
Real World Project Characterization of Glucose
Introduction:
Nuclear magnetic resonance (NMR) is an instrumental technique used to analyze a
molecule to see how close to the predicted chemical structure a sample molecule is. The
instrument uses a very strong magnetic field to analyze the spin of the molecules to see the
structure. Capillary electrophoresis (CE) is a separation technique used to determine the makeup
of a compound. CE uses electrical current to separate out ionic species in the
Glucose is a common sugar found in nature and is essential for life. It is found in many
types of food and is one of the most crucial sugars for humans. Glucose, a monosaccharide, is a
simple sugar and experimentation with it can lead to knowledge of other sugars and how they
bind in the human body. In a biological process the glucose is used to produce adenosine
triphosphate (ATP). This process converts sugars into ATP which is then used within the body
as an energy source to carry our routines in the body.
Purpose:
Glucose will be derivative using 1-phenyl-3-methyl-5-pyrazoloe (PMP). This derivative
will be analyzed for purity using nuclear magnetic resonance (NMR), capillary electrophoresis
(CE) and infrared spectroscopy (IR).
Procedure:
Day 1
Glassware was assembled to perform the experiment. A 0.3 M solution of sodium hydroxide
was prepared by dissolving 1.2016 g of NaOH in 100 mL of water. A 0.5 M solution of PMP
was prepared by dissolving 8.713 g of PMP in 100 mL of methanol. A 0.3 M solution of
hydrochloric acid was prepared by adding 2.5 mL of concentrated HCl in 100 mL of water.
Day 2
1.3512 g of dextrose and 30 mL of PMP were placed in 250 mL round bottom flask. 30 mL of
0.3 M NaOH were added to the flask and the flask was headed with a condenser to 70°C for 30
minutes in a mineral oil bath. After the heating the flask was allowed to cool to room
temperature and 30 mL of 0.3 M HCl to neutralize the reaction. The solution was separated with
190 mL of ethyl acetate three times, the aqueous layer was extracted. The extracted layer was
then rotovaped to evaporate the ethyl acetate out of the sample. The sample was then put on the
lyophilizer to dry the sample.
Day 3
The sample was removed from the lyophilizer and 190 mL was added to dissolve the sample and
the sample was then rotavapped to remove more of the ethyl acetate. The sample was again
lyophilized to remove out the water.
Day 4
The product was analyzed by NMR and CE. A proton NMR was performed as well as a 13C. An
IR was recorded as well.
Data:
Spectra from NMR are in lab manual
CE
Method for CE
PMP spectra peak
Product peak
Conclusion:
Overall, the procedure of the experiment was simple to follow. A difficult point in the
reaction was the maintaining of the temperature of 70°C. The temperate we held at was
approximately 73°C. The scale at which we ran the experiment was three times what another
student was running the experiment for their independent study. The NMR spectrum that was
gathered showed a large solvent peak in the proton NMR. The solvent peak appeared between
4.6 and 4.8 which we believed to mask some of the peaks in our product. The 13C NMR and CE
data was very reliable. The CE PMP peak shows a large peak around 5 minutes which does not
appear in the spectra with the product. This shows that the PMP fully reacted with the starting
materials forming the glucose. The IR data that was analyzed was very promising. The data
showed a lack of a ketone, which is part of the PMP. This shows that the main feature of the
PMP was driven off in our sample. The student performing this experiment for his independent
study did not perform the second hydration and the data obtained from his was not as neat. The
second hydration proved to be a very important part of the procedure.
Reference:
Thibault, Pierre, and Susumu Honda. Capillary Electrophoresis of Carbohydrates. Totowa, NJ:
Humana, 2002.