Abstract
Pulsed UV laser-induced stationary wave capillary vibration (CVL) detection was applied to polymer solution capillary electrophoresis (CE) for a highly sensitive detection of nonderivatized DNA fragments. A waveguide excimer laser (smaller-sized and easier for practical use than a continuous-wave (CW) UV laser) was used as a CVL excitation source. A methylcellulose solution was used as a separation medium. It was found that the fluidity of a methylcellulose solution resulted in a long duration (>one day), as in the case of a free solution, even though the nano-second pulse energy was nearly one-thousand times as large as that of intensity-modulated CW laser light. Nonderivatized DNA fragments (ca. 60 μM) were used as a sample; both CE separation and CVL detection were performed. No fatal damage to the separation medium was observed. The lower detection limit (S/N=2) of the absolute amount was calculated to be 7 attomole, which showed that the sensitivity using a polymer solution was not inferior to that using a free solution. These results showed the feasibility of polymer-solution CE/pulsed CVL to the practical analysis of biopolymers, such as sequencing and DNA diagnosis.