UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

Size characterization of particles using capillary electrophoresis Khodabandehloo, Akram


Taylor dispersion analysis (TDA) can be used for characterizing size of particles over a wide range. This method is performed on a capillary column and its simplicity and reproducibility offer many advantages over other more commonly used techniques for sizing. In the first part of the thesis, different sizing techniques are reviewed and their advantages and disadvantages are discussed. In the second part of this thesis, numerical modeling is used to optimize the operating conditions for performing TDA. In addition, the validity of TDA conditions is verified and the optimum conditions for performing TDA are discussed. Also, the effect of electric field on the validity of TDA and its application for a mixture of molecules with different sizes is studied. It is concluded that care must be taken to choose parameters in a way that lead to optimal TDA results. For the mixtures, using electric field is advantageous, because it not only leads to separation of molecules but also gives information on the charge of the molecules. In addition to numerical modeling, the equations for TDA to be used in the presence of electrophoretic mobility are modified and compared to the diffusion coefficients obtained using classical TDA. In this part of thesis, in addition to pressure, voltage is also applied to separate the components of mixtures and characterize the size of individual species. The results indicate that using the modified equations make the resulting values more consistent with the ones obtained from classical TDA. Our method can be used for mixtures, and in this thesis, a preliminary attempt has been made to characterize the size and charge of a mixture of proteins and peptides and amino acids. The final part of this thesis discusses the dispersion of proteins and small peptides during electrokinetic migration. Like conventional Taylor dispersion, peak broadening is more prronounced for particles with smaller diffusion coefficients. The theoretical description of band broadening caused by electroosmotic flow dispersion (EOFD) and the experimental verification of this phenomenon are presented.

Item Citations and Data


Attribution-NonCommercial-NoDerivatives 4.0 International