Chapter 6 - MATLAB

In lab, we learned that it is common practice to represent the release as a percentage of the initial amount. The initial amount of mehtylene blue in each trial was (9mL)*(5.9mg/mL). The concentration in solution was divided by this value to determine the release as a percent.

When the data was processed into Matlab, releases exceeding 100% were observed. This is of course impossible. The mass in solution was greater than the initial mass by a small amount. This discrepancy can be explained by the error in the callibration curve. The y-intercept was greater than any of the errors in the trials. Because the y-intercept for the callibration curve should be 0, the y-intercept was excluded from subsequent calculations.

Plots:

Attempting to fit an exponential curve to each of these, the natural logarithm of the difference was taken: ln(1-release). Running a linear regression for each of these:

R² = 0.9843

R² = 0.9880

R² = 0.9914

The slopes and y-intercepts of these lines can be used to form an exponential curve to fit the time vs. release data. Additionally, these slopes can be compared with concentration of sodium alginate to find a relation between release rate and preparation of alginate.