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RECEIVED for review May 10, 1991. Accepted July 31, 1991. This research was supported by the State of Texas Advanced Research Program, the Electric Power Research Institute through Grant RP 1630-55,and the U.S.Department of Energy through Grant DE-FG05-84ER13281. This manuscript has not been subjected to review by any of the above agencies and no endorsement should be inferred.
Ultrasensitive Detection for Capillary Zone Electrophoresis Using Laser- Induced Capillary Vibration Jiaqi Wu, Tamao Odake, Takehiko Kitamori, and Tsuguo Sawada* Department of Industrial Chemistry, Faculty of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113, Japan
The lamr-lnduced capllary vlbratlon method (CVL), a novel photothermal method, has been applled to ontolumn ultrasenrltlve detectlon of nonlabeled analytes separated by capillary zone electrophorerk (CZE). The feadblllty and performance of the combhod CZEKVL were "edby uslng v W e excltatlon wlth rlboflavln as a sample. The lower detectlon llmlt of absorbance was 1.8 X lo-' for a 80-pm caplllary, and the correrpondlng abedute amount was 80 amol, when the 476-nm, 40mW laslng line of an argon laser was the vlslble excltatlon beam. These results were at least 3 orders wperlor to conventional absorptlon detectors and are of the same order as Iaser-lnduced fluorometry for rlboflavln. Next, UV exxdlatbn was appWed to the delectbn of nonlabebd amlno aclds separated by CZE. The second harmonlc of the argon laser (257.2 nm, 5 mW) was used for excltatlon, and 15 ?molof tryptophan and 110 fmol of phenylalanlne were detected without derlvatlzatlon.
INTRODUCTION Capillary zone electrophoresis (CZE) offers a powerful method for separations of samples in ultramicro quantities ( I ) . Its significant advantages are fast and high efficient separation, with the number of theoretical plates reaching 105, and the extremely small sample volume (
