Separation of modified nucleic acid constituents by micellar electrokinetic capillary chromatography

Micellar electrokinetic capillary chromatography offers a high-resolution microanalytical technique useful for adducted and modified nucleic acid constituents. A mixture of 14 normal and modified deoxyribonucleosides, deoxyribomononucleotides, a ribonucleoside and a pyrimidine can be resolved in less than 40 min using 10 kV of separating voltage, 0.075 M sodium dodecylsulfate micelles in phosphate-borate buffer, and a 68.5 cm X 60 micron I.D. fused-silica column. Efficiencies up to 370,000 theoretical plates (540,000 plates/m) are achieved, but are highly dependent on solute concentration. The limit of detection for 2'-deoxyguanosine under high-resolution conditions is ca. 18 pg at a signal-to-noise ratio of 4, but the very small injection volumes (ca. 1.5 nl) limit the minimum detectable sample solution concentration to ca. 42 nmol/ml.