The use of a micropump based on capillary and evaporation effects in a microfluidic flow injection chemiluminescence system.

The performance of a micropump operating on evaporation and capillary effects, developed for microfluidic (lab-on-a-chip) systems, was studied employing it as the fluid drive in a microfluidic flow injection (FI) system, with chemiluminescence (CL) detection. The micropump featured simple structure, small dimensions, low fabrication cost and stable and adjustable flow-rates during long working periods. Using a micropump with 6.6cm(2) evaporation area, with the ambient temperature and relative humidity fluctuating within 2h in the ranges 20-21 degrees C and 30-32%, respectively, an average flow-rate of 3.02muL/min was obtained, with a precision better than 1.2% R.S.D. (n=61). When applied to the microchip FI-CL system using the luminol/hexacyanoferrate/H(2)O(2) reaction, a precision of 1.4% R.S.D. (n=11) was obtained for luminol at a sampling frequency of 30h(-1).