Class: BE210
Group: R6
Members: FACILITATOR
..Adam
Furman
TIME & TASK KEEPER
.
..
Arika Goel
SCRIBE
..Heather Lee
PRESENTER . .Howard Lopez
BIOENGINEER .Franklin Shen
Date: May, 2001
Abstract:
The main objective of the experiment was to determine and program an
algorithm that would generate the pH (within a range of 2 to 12) of an
unknown solution containing Yamada or Bogens universal indicator, given
a survey scan of such a solution. To obtain solutions of differing pH values,
various amounts of HCl and NaOH were added to the universal buffer to modify
the pH as needed. Survey scans were taken at pH increments of 0.5 (and
0.1increments were taken for pH values from 4 to 6). Three-dimensional
graphs of absorbance vs. wavelength vs. pH for solutions containing either
of the universal indicators showed that absorbance vs. wavelength graphs
at various pH values had only one peak, with the appearance of another
peak for survey scans of the middle pH values. Since graphs at most pHs
had only one peak, an algorithm was constructed in Microsoft Excelâ
to determine the pH by comparing the wavelength and absorbance at the max
peak of an unknown sample solutions survey scan with survey scans of known
pH values. The pH value whose characteristics (max peak wavelength and
absorption) differ least was declared to be the output pH. The uncertainty
for the algorithm was found to be +/- 1.2 for the Yamada indicator and
+/- 1.3 for the Bogens indicator.