relation: http://d-scholarship-dev.library.pitt.edu/8075/
title: Better Separations for Proteins and Peptides
creator: Li, Ling
description: In recent years, determination of proteins and peptides has been gaining more popularity. However, one-dimensional separation systems cannot always offer sufficient sensitivity or selectivity, especially for more complex samples. Two-dimensional separation systems can provide more peak capacity by coupling two orthogonal separation methods together. To achieve better two-dimensional separation, two conditions must be satisfied: 1. the two coupled separation methods should have different separation mechanisms, so called orthogonal; 2. the second dimensional separation method should be much faster than the first dimension to ensure that more effluent from the first dimension be transferred to the second dimension. Capillary electrophoresis, with its different separation mechanism from HPLC, and its high separation speed, serves as a good candidate as the second dimension separation method when HPLC serves as the first dimension separation method. In addition, chip electrophoresis is more advantageous to us due to its faster speed and more efficiency compared to capillary electrophoresis. Therefore, we would like to set up a two-dimensional separation system with the first dimensional HPLC separation followed by the second dimensional chip electrophoresis separation. As for HPLC, elevated temperature is utilized to increase the separation speed. The viscosity of the solvent is related to temperature in such a way that higher temperature leads to lower viscosity. The diffusion coefficient of the solute is therefore decreased based on Stokes-Einstein equation ( ). As a result, higher linear velocities can be achieved with regular pressure. It is suggested that diffusion coefficient plays such an important role in affecting the separation speed that efforts are deserved to investigate how diffusion coefficient changes with temperatures. In our experiment, we would like to determine the diffusion coefficients of several peptides and compare the experimental values with estimation values from various empirical equations.
date: 2008-09-28
type: University of Pittsburgh ETD
type: PeerReviewed
format: application/pdf
language: en
identifier: http://d-scholarship-dev.library.pitt.edu/8075/1/LingLi062008.pdf
identifier:   Li, Ling  (2008) Better Separations for Proteins and Peptides.  Master's Thesis, University of Pittsburgh.    (Unpublished)