紫外光發光二極體誘導螢光偵測法結合毛細管電泳/線上濃縮技術之開發與應用

Abstract

本篇實驗應用紫外光發光二極體（UV-LED）誘導螢光搭配毛細管電泳層析技術，並結合線上濃縮技術對於螢光性（核黃素）及非螢光性（色氨酸）進行偵測。本實驗所使用的UV-LED發光波長在380 nm，功率約在2 mW。在偵測核黃素的部分使用速度變化誘導聚焦(Velocity-Difference Induced Focusing, V-DIF)來進行實驗，成功將偵測極限由原來僅使用微胞電動電泳層析的200ppb提高到3~7ppb。在色氨酸的偵測部分，則利用螢光試劑衍生色氨酸，使其適合UV-LED的激發，並利用掃集技術（sweeping）將偵測極限從原來使用微胞電動電泳層析的1.5ppm提高至3ppb。在真實樣品的應用上分別偵測啤酒裡面的核黃素，以及尿液、牛奶裡面的色氨酸均可以成功快速達到定性及定量的結果。

Abstract 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 UV-LED (peak emission wavelength at 380 nm, ~ 2 mW) for fluorescence detection is demonstrated by examining a naturally fluorescent (riboflavin) and a non-fluorescent compound (tryptophan), respectively. The detection limit for riboflavin was determined to be 0.2 ppm by the normal MEKC mode and this was improved to 3 ~ 7 ppb when a dynamic pH-junction techniques were applied. On the other hand, the detection limit of the tryptophan derivative was determined to be 1.5 ppm using the MEKC mode and this was improved to 3 ppb when the sweeping-MEKC mode was applied. In an analysis of an actual sample, the concentrations of riboflavin and tryptophan in beer and urine/milk samples were determined, respectively.