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UV-VIS pH 4-13
Glutamine pH 12 and 13 strained the test tube a pink color, but failed to display any significant absorbance The same was observed with Arginine pH 12 and 13, except the stain was a purple
The graphs above contains absorbance data from our Arginine solutions of pH 4-13 with constant ionic strength. The solutions of lower pH appear to have the best absorbance, with pH 4 being the best, pH 5 being the second best and pH 6 being the third, all of which are significantly higher in absorbance than all other solutions. The solution of pH 9 had the lowest absorbance of all of the solutions. All solutions lacked any significant isolated peak in the range of 500-600 nm.
The graph above contains absorbance data from our N-capped Arginine solutions of pH 4-13 with constant ionic strength. Solutions of pH 4 and 5 did not experience any peaks but did experience a higher absorbance throughout the spectrum. These solutions also appear to sweep up earlier in the spectrum. pH 6 had this trend as well but it was not as severe or early as pH 4 or 5. All 5 solutions of pH 7 - 9.6 had peaks in the range of interest where we expect nanoparticles to form. Of these solutions there was inconsistencies in the magnitude of the peak, as pH 7, 8.8, and 9.6 were all similar whereas pH 9 and 8.255 were lower. Solutions of pH 12.76 and 13.26 experienced the lowest absorbance, and did not display any peaks.
The graph above contains absorbance data from our Glutamine solutions of pH 4-13 with constant ionic strength. This trial had a nice trend where the lower pHs had the higher absorbance experienced. This trend was followed from pH 4-9, wit the exception of pH 8.8, which was lower than pH 9. pH 12.76 had the lowest absorbance, whereas pH 13.26 had an absorbance higher than 8.8, 9.63, and 12.76. All of the solutions appear to have a relative plateau above 500 which experiences a slight divot at 500 nm.
The graph above contains absorbance data from our Histidine solutions of pH 4-13 with constant ionic strength. As previously seen in other trials, all the solutions have absorbance at 280 nm, which is due to the aromatic ring on histidine's side chain. As seen in other solutions run in this trial, pH 4, 5, and 6 experienced a higher broad absorbance throughout the spectrum. Solutions of pH 8.8 and 9.63 had the largest peaks observed in the range of interest, followed by pH 7. pH 12.76 experienced the lowest absorbance, just being pH 13.26. pH 8.255 and 9 were also lackluster in formation of nanoparticles.