How Side Chains Altering The Ionizability Of Our Three Amino Acid

The goal of our experiment was to compare how side chains alter the ionizability of our three amino acids: alanine, aspartic acid, and cysteine. More specifically, we wanted to observe how a thiol group and a carboxyl group affected the ionizability of the rest of the amino acid. Because alanine contains a single methyl group on its side chain, we can easily compare the functional groups of aspartic acid and cysteine to it because both aspartic acid and cysteine start their side chains with a methylene group and then go on to add one more respective functional group thus eliminating extraneous variables.
We can easily compare the data using graphs. Each graph of the amino acids above contain three plateaus: two horizontal and one vertical. The vertical plateau, found at the center of the steep part of the graph, is known as the point of equivalence. Here, the moles of NaOH are equivalent to the moles of acid in the original sample (2). The horizontal plateaus can be found at the beginning and the end of the graphs. The first plateau
We used two different pH probes with two different stock solutions for calibration to measure our three amino acids. If one of the stock solutions did not match the inputted pH, this could have resulted in inaccurate measurements. The vernier calipers also were not acting appropriately. Often times the computer stopped calculating pH and we had to reset it. This could also cause change in calibration. Another reason these values could have been incorrect is the increments we were adding our base. We added 1 mL of 0.1 M NaOH at a time. If we made smaller increments we might have been able to read the graphs more accurately to determine where the plateau lies. Other things to consider would be human error due to the precise measurements needed to make our amino acid concentrations and measuring the