Parameters Affecting Capillary Electrophoretic Separation of DNA

Since its introduction in 1930 by Tiselius (1 ), slab-gel electrophoresis (SGE) has been utilized as an important separation technique in molecular biology for the resolution of DNA fragments, polymerase chain reaction (PCR) products, polynucleotides, proteins, and other compounds. Capillary electrophoresis (CE) which was introduced in 1981 in its modern and practical instrumental format by Jorgenson and Lukacs (2 ) for the separation of charged molecules, has been adapted by analytical biochemists for the same applications that SGE can perform, but faster and cheaper with high resolution. SGE allows the application of multiple samples on the same slab gel. Array capillary electrophoresis and microfabricated, capillary array electrophoresis microplates (microchips) allow the simultaneous sequencing of 96 DNA samples using the same instrument. CE offers high resolution, speed, automation of sample handling and analysis, uses small sample volumes (nL), and produces minimum waste. Also, CE with laser-induced fluorescence (LIF) allows sensitive detection in the zeptomole range. Today CE has been applied for the analysis of oligonucleotides, restriction digests, point mutations, DNA-protein and protein-drug interactions, and PCR products (3 –23 ).