Quantitative description of migration behavior of porphyrins based on the dynamic complexation model in a nonaqueous capillary electrophoresis system

Michael T. Bowser, Ethan D. Sternberg, David D Y Chen

Research output: Contribution to journalArticlepeer-review

58 Scopus citations

Abstract

The effect of an additive (Brij 35) on the mobilities of a group of porphyrin acids is quantitatively characterized based on a 1:1 dynamic complexation model. Varying additive concentration shifts the equilibrium and changes the viscosity of the background electrolyte. The equilibrium constant, the electrophoretic mobility of the free analyte, and the electrophoretic mobility of the complex are identified as the parameters necessary to describe the analytes' migration behavior. Several statistical methods for obtaining these parameters are discussed. The equilibrium constants and complex mobilities are calculated using three different linear regression methods. The weighted y-reciprocal method was preferred because it gives smaller error, and the data points are evenly distributed along the concentration axis. These values are confirmed using a nonlinear regression to ensure that the proper weighting was used in the linear regression plots. The parameters are then used to predict the apparent mobilities of the analytes over the entire additive concentration range, allowing the optimum separation conditions to be identified. For disc-like molecules, such as porphyrins, the mobility is determined by the orientation of the molecule in an electric field, in addition to their size and charge. The strength of binding between the porphyrins and Brij 35 depends on the number of binding sites and the solvation shell.

Original languageEnglish (US)
Pages (from-to)82-91
Number of pages10
JournalELECTROPHORESIS
Volume18
Issue number1
DOIs
StatePublished - Jan 1 1997

Keywords

  • Additives
  • Dynamic complexation
  • Nonaqueous capillary electrophoresis
  • Porphyrin
  • Separation theory

Fingerprint Dive into the research topics of 'Quantitative description of migration behavior of porphyrins based on the dynamic complexation model in a nonaqueous capillary electrophoresis system'. Together they form a unique fingerprint.

Cite this