Abstract − Analytical Sciences, 22(2), 235 (2006).
UV Light-Emitting Diode-Induced Fluorescence Detection Combined with Online Sample Concentration Techniques for Capillary Electrophoresis
Yen-Sheng CHANG, Chun-Min SHIH, and Cheng-Huang LIN
Department of Chemistry, National Taiwan Normal University, 88 Sec. 4, Tingchow Road, Taipei, Taiwan
The application of an ultraviolet (UV) light-emitting diode (LED) to on-line sample concentration/fluorescence detection in capillary electrophoresis (CE) is described. The utility of a UV-LED (peak emission wavelength at 380 nm, ∼2 mW) for fluorescence detection was demonstrated by examining both a naturally fluorescent (riboflavin) compound and a non-fluorescent compound (tryptophan), respectively. The detection limit for riboflavin was determined to be 0.2 ppm by the normal MEKC mode, which was improved to 3 - 7 ppb when dynamic pH-junction technique was applied. On the other hand, the detection limit of the tryptophan derivative was determined to be 1.5 ppm using the MEKC mode, which was improved to 3 ppb when the sweeping-MEKC mode was applied. In an analysis of an actual sample, the concentrations of riboflavin in beer, and tryptophan in urine and milk samples were determined, respectively.
J-STAGE:
View this article in J-STAGE
Back to the Table of Contents
