Calculation of Absorbance Coefficients of Individual Species of Amino Acids in Aqueous Solutions Using Target Factor Analysis and Nonlinear Regression

In an amino acid aqueous solution, simultaneously, there are different species, for example in the serine aqueous solution there are three different species H?L?,HL and L?. Here, L denotes the fully deprotonated ligand. In this investigation, an attempt has been made to calculate the absorbance coefficients of individual amino acids in UV_Visible range by means of nonlinear regression and target factor analysis. Furthermore, these results have been compared. The investigations show that the peak of H?L?,HL and L? are completely different in such a way some species are light absorbent and the other species are not. To obtain pure spectra of each species using nonlinear regression some suitable conditions must be introduced to nonlinear regression algorithm. On the other hand, if suitable conditions are introduced, nonlinear regression can produce good results regardless of low or high absorbencies.Target Factor Analysis is the better method when the absorbencies are high. In regions with low absorbencies incorrect results can be produced by TFA.