Fabrication of an integrated PDMS microchip incorporating an LED-induced fluorescence device

A micro fluidic device with an integrated fluorescence detection system has been developed in order to miniaturize the entire analytical system. A blue or green light-emitting diode ( LED) and an optical fiber were mounted in a polydimethylsiloxane- based microchip. The performance of this device was evaluated by microchip electrophoresis. When a green LED was used as the light source, the calibration curve of Sulforhodamine-101 was linear over the range 1-100 mu M. The detection limit was found to be 600 nM ( 240 amol) for a S/N ratio of 3. When using a blue LED, the calibration curve of Fluorescein was linear over the range 0.2 100 mu M. The detection limit was estimated to be 120 nM ( 50 amol) (S/N= 3). The detection sensitivity per unit power was comparable to that of LIF. The RSD values for the migration time, peak height and peak area were 0.74, 7.18 and 9.45%, respectively. The integrated micro fluidic device was successfully used to determine amino acid derivatives.