Microchip capillary electrophoresis using on-line chemiluminescence detection

Chemiluminescence detection was used in capillary electrophoresis integrate d on a microchip. Quartz microchips have two main channels and four reservo irs. Dansyl-lysine and -glycine were separated and detected with bis[(2-(3, 6,9-trioxadecanyloxycarbony)-4-nitrophenyl)]oxalate as peroxyoxalate chemil uminescent reagent. These dansyl amino acids came into contact with the che miluminescence reagent to produce visible light at the interface between th e separation channel and chemiluminescence reagent-containing reservoir. Th e detection limit (S/N=3) for dansyl-lysine was 1 . 10(-5) M, which corresp onded to the very small mass detection limit of ca. 0.4 fmol. However, the concentration sensitivity in the present system was approximately two order s of magnitude lower than that in the conventional capillary electrophoresi s-chemiluminescence detection system. The relative standard deviations of m igration time and peak height for dansyl-lysine were 4.2 and 4.5%, respecti vely. A channel conditioning before every run and an appropriate control of voltages were needed for the reproducible results. The present system had advantages in rapid separation time (within 40 s), small (several 10 pi) an d accurate sample injection method using a cross-shaped injector, and simpl ification and miniaturization of the detection device. (C) 2000 Elsevier Sc ience B.V. All rights reserved.