Date of Completion


Thesis Advisor(s)

Xudong Yao

Honors Major



Analytical Chemistry


Proteome quantification is a complicated process which takes on many methods, usually involving peptide derivatization and complex mass spectral analysis. Scores of techniques have been utilized to address issues of incomplete quantification. The implementation of IPTL labeling, or isobaric peptide terminal labeling, is a recent addition to the literature, which exploits the supposedly selective labeling of N-termini of tryptic peptides from the C-termini of lysine residues due to differences in basicity. This method has been shown to improve quantitation by reducing spectral complexity and provide more accurate and reproducible results on peptide abundance. Investigations into the selectivity of terminal derivatization have been lacking luster and provide little explanation for the chemical nature behind the fact of the selectivity of terminal labeling. This paper will investigate selectivity across various Lys-containing tryptic peptides, accounting for pH change, reaction time, labeling concentration, and selected aldehydes. It will also describe the use of an automated liquid handler from Opentrons, which is utilized to improve reproducibility, and reduce analyst error and deviation, via standardization of technique.