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Better Separations for Proteins and Peptides

Li, Ling (2008) Better Separations for Proteins and Peptides. Master's Thesis, University of Pittsburgh. (Unpublished)

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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.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Li, Linglil38@pitt.eduLIL38
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairWeber, Stephen G.sweber@pitt.eduSWEBER
Committee MemberMichael, Adrianamichael@pitt.eduAMICHAEL
Committee MemberAmemiya, Shigeruamemiya@pitt.eduAMEMIYA
Date: 28 September 2008
Date Type: Completion
Defense Date: 19 May 2008
Approval Date: 28 September 2008
Submission Date: 11 June 2008
Access Restriction: 5 year -- Restrict access to University of Pittsburgh for a period of 5 years.
Institution: University of Pittsburgh
Schools and Programs: Dietrich School of Arts and Sciences > Chemistry
Degree: MS - Master of Science
Thesis Type: Master's Thesis
Refereed: Yes
Uncontrolled Keywords: 2D separation; diffusion coefficients
Other ID:, etd-06112008-111627
Date Deposited: 10 Nov 2011 19:46
Last Modified: 15 Nov 2016 13:44


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