CMOS LIF detection system for capillary analysis

We present a laser-induced fluorescence (LIF) detection system for capillary analysis. It is designed with right-angle laser excitation on a capillary and fluorescence detection by a CMOS buried double p-n junction (BDJ) detector. Noise-reduction techniques are implemented in the associated electronics and the digital processing part. By measuring a solution injected in the capillary, the system indicates the detected fluorescence intensity for concentration determination, as well as its average wavelength for molecular identification. The system is tested using fluorescein isothiocyanate (FITC) solutions. The experimental results obtained by measuring a small volume of 5 nl show that a low concentration of 10(-10) M is detectable. Measurements are verified by comparison with other experimental techniques using a spectrofluorimeter and a cooled CCD camera. (C) 2003 Elsevier B.V. All rights reserved.