Today, as soon as I arrived, I was
put to work as to making the two buffers. Applying the knowledge that I learned
last week—about finding the correct calculations pertaining to the measurement
of the particular substance—, I was asked to find the target amount. When last
week, I dealt with a liquid (though only hypothetical because I didn’t actually
get to create the mixture), this week, I prepared a buffer using solids: Na4O7P2
(446.06 Mw) and H2Na2O7P2 (221.94
Mw). Wanting a total volume of 20mL in each of the two buffers that I was going
to prepare, I found the weight of the former and latter solutions needed in
grams. To do this I used the formula: weight of solute (g)= formula weight of
solute (g/mol) x molarity (mol/L) x final volume (L). After finding the
measurements 1.7624g and 0.8878g respectively, all was left for me to do was
put combine the various components into their vials.
After having prepared this, Yolanda
told me that we were looking to attain a mixture of the two buffers with a pH
of 7. Unfortunately, we were not able continue with the next steps because the Na4O7P2
did not dissolve with the H20 as expected. This said, my
mentor did walk me through the steps that we would have performed had the
substance dissolved. By using the pH measuring apparatus, we would—similar to
that of trial-&-error—pour in a new vial a portion of the H2Na2O7P2,
which had a pH of 10, and Na4O7P2, which had a
pH of 6. Using the pH machine, we would add a little bit of each until the
number 7 pops on the screen, thus indicating us that our target goal has been
achieved.
In a broader scope, this pertains
to the entire goal of capillary electrophoresis (electrophoresis separates
macromolecules by size, charge, and/or properties) as a buffer is needed for
the conduction of charge. This charge is transmitted by the ions provided by
the buffer. In addition, “the buffer, by providing a reservoir of weak acid and
base, also keeps the pH within a narrow range. This is important because the
structure and charge of a protein or nucleic acid will change if subjected to
significant pH changes, thus preventing proper separation.”
Next week, my mentor and I are
hoping that the substance will have dissolved and then go from there to
continue what we left unfinished today.
The Purpose of Buffer in Electrophoresis. Retrieved from
http://www.ehow.com/about_6613320_purpose-buffer-electrophoresis.html.
Seems like you are making progress. I am looking forward to the day when you actually run electrophoresis!
ReplyDeleteI like how you added text to your image. It makes the photograph even more useful.
Keep up the good effort!