?url_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Adc&rft.relation=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F8075%2F&rft.title=Better+Separations+for+Proteins+and+Peptides&rft.creator=Li%2C+Ling&rft.description=In+recent+years%2C+determination+of+proteins+and+peptides+has+been+gaining+more+popularity.+However%2C+one-dimensional+separation+systems+cannot+always+offer+sufficient+sensitivity+or+selectivity%2C+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%2C+two+conditions+must+be+satisfied%3A+1.+the+two+coupled+separation+methods+should+have+different+separation+mechanisms%2C+so+called+orthogonal%3B+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%2C+with+its+different+separation+mechanism+from+HPLC%2C+and+its+high+separation+speed%2C+serves+as+a+good+candidate+as+the+second+dimension+separation+method+when+HPLC+serves+as+the+first+dimension+separation+method.+In+addition%2C+chip+electrophoresis+is+more+advantageous+to+us+due+to+its+faster+speed+and+more+efficiency+compared+to+capillary+electrophoresis.+Therefore%2C+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%2C+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%2C+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%2C+we+would+like+to+determine+the+diffusion+coefficients+of+several+peptides+and+compare+the+experimental+values+with+estimation+values+from+various+empirical+equations.&rft.date=2008-09-28&rft.type=University+of+Pittsburgh+ETD&rft.type=PeerReviewed&rft.format=application%2Fpdf&rft.language=en&rft.identifier=http%3A%2F%2Fd-scholarship-dev.library.pitt.edu%2F8075%2F1%2FLingLi062008.pdf&rft.identifier=++Li%2C+Ling++(2008)+Better+Separations+for+Proteins+and+Peptides.++Master's+Thesis%2C+University+of+Pittsburgh.++++(Unpublished)++