Electrophoresis is the technique used to characterize proteins, oligonucleotides, and DNA. Methods employed to date include gel and capillary electrophoresis. Most samples can be characterized by these methods. However, large DNA molecules do not separate well with either method. A newer electrophoresis method involves the use of the Doppler effect to determine a particle’s characteristics. This thesis is concerned with the design and development of an open geometry Doppler electrophoresis instrument for macromolecular characterization in solution where gel characteristics and electroosmotic flow need not be considered. / Master of Science