Absorption analysis at different pH levels

Glucose absorption analysis at
different pH levels
Erich Awender (Introduction)
Matt Lopez (Method)
Mitch Powers (Results)
Hasani Morrow (Discussion)
• The goal of our experiment is to demonstrate how
different pH levels will affect the break down of
• The absorption of glucose at 540 nm will be affected
by different levels of pH.
• Higher absorption at a lower pH
• Lower absorption at a higher pH
Background info
• A previous study by Zuping Tang, Xiaogu Du,
Richard Louie, and Gerald Kost was very
similar to ours
– Also tested glucose absorption at higher and
lower pH levels
– Found that with normal glucose levels the
difference in pH was not significant
– However, increased levels of glucose showed a
higher absorption at higher pH and lower
absorption at lower pH
First off we labeled the tubes so we did not
mix them up, then we added the saliva
solution to all the tubes. Then we filled three
tubes with a high pH, three with a low pH,
three with a neutral pH, and one without any
added pH since it was the control in the
experiment. Afterwards we added the DNSA
and buffer at the same time intervals so we
could be as accurate as possible.
After we got all the test tubes ready we put them on a hot plate and we
started to turn up the heat to get them bubbling a bit. We kept them on the
hot plate for five minutes then took them out and put them back into the
racks into their groups.
After we had all the test tubes separated we put small samples of each
mixture and put samples of them into cuvettes and lined them up based on
their group. After we had all that done we put them into the spectrometer
and recorded the absorbance they showed at 540 nm.
• Dnsa – When DNSA is reduced it yields 3 amino, 5
nitrosalicylic acid, and deeply colors a compound which
absorbs strongly at 540nm
• The relationship between change in color for the acids and
bases were generally the same color but were a little darker,
while the neutral was the darkest one because it absorbed the
most glucose while the acidic and basic test tubes absorbed
less and were generally the same color.
• pH is used as a scale to show how acidic or basic a certain
substance is. Less than 7 is acidic, 7 is neutral, and more than
7 is basic. A buffer is a solution that has a very stable pH, and
adding an acid or base should not affect it much and adding
water should not change the pH of the buffer.
The Basic and Acidic glycogen are not significantly different with a p
value =(0.37)
The Basic and Neutral glycogen are significantly different with a p
The Acidic and Neutral glycogen are significantly different with a p
value =(.03)
Let’s Discuss Shall We
• Our hypothesis was that the absorption will
be affected by different PH’s
• We predicted that there will be a higher
absorption at a lower PH
• A lower absorption at a higher PH
• And that the neutral PH would fall in between
the two extremes
Our Expectations
• The different PH’s did affect the absorption of the
glucose however not in the way we predicted.
• We thought that a higher PH would result in less
absorption and that a lower PH would result in
more, but the absorption levels for both were very
similar. Basic having a higher absorption level by
only .001nm
• The neutral PH which we thought would be in
between the acidic and basic actually had the
highest amount of absorption.
Similar Studies
• According to a similar experiment done by Zuping
Tang, MD; Xiaogu Du, MD; Richard F. Louie, BS;
Gerald J. Kost, MD, PhD in 2000 the higher PH
resulted in higher absorption and the lower
resulted in lower absorption.
• Compared to our results theirs were significantly
different however in the article it said they were
using much more sophisticated equipment.
"Archives of Pathology & Laboratory Medicine Online - Error." Archives of Pathology &
Laboratory Medicine Online - Error. N.p., n.d. Web. 26 Sept. 2012.
So What Now?
• The questions that we had after our
experiment were:
• Why was the neutral PH so much higher?
• Why were the acidic and basic PH’s so similar?

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