Abstract: Three types of flow reactors with different lengths (12-126 mm) and widths (0.4-2.0 nun) of channel were made on the silicon chip by microfabrication techniques for the chemiluminescent (CL) detection of epinephrine (EP) with lucigenin (Luc). The volume of each CL reactor was about 10 µL. A solution containing EP and Luc and a solution containing NaOH and periodate were injected successively into each inlet of the CL reactor in the range 20-100 µL/min with a pressure-driven flow system. The intensity of light emission was dependent on the geometry of the flow reactors. These results could be explained in terms of the differences in the diffusion length of the reactants in the flow reactors. The maximum light emission were linearly correlated, with the concentrations of EP over the range from the detection lit-nit of 5.0 x 10^-8 mol/L up to 5.0 x 10^-6 mol/L on the use of the CL reactor with the most promising geometry.

Abstract: The chemiluminescent (CL) detection of epinephrine (EP) with lucigenin (Luc) was performed using a µflow cell fabricated on a silicon chip. A solution of EP was injected into the Luc carrier stream. The Luc solution containing EP and an alkaline solution were successively poured into the flow cell by a pressure-driven flow system. Two types of flow cells were fabricated for estimating the effect of the mixing modes in the flow cells on the intensity of light emission. In flow cell 1, two streams entered through separate inlet ports and merged to flow adjacently. In flow cell 2, a Luc solution containing EP was split up to 36 partial flows by passage through the nozzles, and was injected into the alkaline solution. The intensity of light emission in flow cell 2 increased markedly compared to that in flow cell 1. The detection limit of 8.0 x 10^-7 M for EP in flow cell 2 was a factor of six-times better than that in flow cell 1. The improvement in the sensitivity for EP could be explained in terms of the distortion of laminar flow in flow cell 2.