Histidine Standard Lab Report
IIn part A, the unknown 30 was identified as Histidine by using a thin layer chromatography. Among the four amino acid standards (Ala, Gly, His, and Ser), the average Rf value of the unknown (0.31) was closest to that of standard Histidine (0.29) and its Rf percent error was lowest (6.9%). Furthermore, the color, shape, and size of the unknown clearly corresponded to that of Histidine standard. Overall, the experiment was successful in identifying the unknown amino acid, for the obtained Rf and color were very distinct from each other. Because Histidine was a basic amino acid, it had three ionizable groups: a carboxyl group, an amino group, and a basic side chain. The titration curve (graph 2) clearly corresponded to the result obtained from