Abstract:

Based on the metal ion-catalyzed luminol–peroxide reaction, several different configuration microchip have been compared. Influencing factors of chemiluminescence sigals, such as concentration and flow rate of reagents and scale of microchannels have been discussed. We proposed a new microflow injection system with double spiral channel configuration and the sensitivity was greatly enhanced due to more efficient mixing of the analyte and reagent solutions. Under the optimized conditions, a linear calibration curve (R2 = 0.997) over the range 5.0 × 10-9 to 2.0 × 10-6 mol L-1 was obtained with the detection limit of 1.50×10?9 mol L?1 for the chromium ion. The relative standard deviation was found to be 1.59 % (n = 11) for 6.0×10?8 mol L?1. The proposed method has been applied successfully to the analysis of natural lake water and tap water.