Ms. Liu et al., DOUBLE-STRANDED DNA ANALYSIS BY CAPILLARY ELECTROPHORESIS WITH LASER-INDUCED FLUORESCENCE USING ETHIDIUM-BROMIDE AS AN INTERCALATOR, BioTechniques, 18(2), 1995, pp. 316
We have developed a rapid and sensitive method to analyze double-stran
ded DNA by capillary electrophoresis equipped with a laser-induced flu
orescence detector. Using ethidium bromide as an intercalator in polya
crylamide gel-filled capillaries along with a green He/Ne laser source
(excitation: 543 nm; emission: 600 nm), we found the detection sensit
ivity for a single DNA-ethidium bromide complex was in the picogram le
vel with a resolution of one base pair separation between two DNA frag
ments. In the case of the separation of a phi X174 DNA-HaeIII digest,
sizes from 72 to 1353 bp were well resolved within 12 min. For the ana
lysis of PCR-amplified DNA, low levels of amplified DNA fragments coul
d be detected that could not be visualized in agarose gel after standa
rd ethidium bromide staining. Considering the high resolving power and
sensitivity, we believe that this method can be a useful tool for the
analysis of double-stranded DNA especially for PCR-amplified DNA frag
ments.