Chemiluminescence detection for Co (II) based on luminol-hydrogen peroxide reaction on a microfluidic chip

A simple and effective method for the determination of Co (II) in water on a PDMS microfluidic chip with chemiluminescence (CL) detection is presented. The CL reaction was based on oxidation of luminol by hydrogen peroxide in basic aqueous solution. The microfluidic chip was designed and fabricated from polydimethylsiloxane (PDMS) using micro-molding method. Optimised reagents conditions were found to be 7.0 × 10−4 mol/L luminol, 7.0 × 10−2 mol/L hydrogen peroxide, and 0.10 mol/L sodium hydroxide. In the continuous flow injection mode the system can perform fully automated detection with a reagent consumption of only 4.5 μL each time. The linear range of the Co (II) ions concentration was 1.0 × 10−10 mol/L to 1.0 × 10−3 mol/L, and the detection limit was 4.4 × 10−11 mol/L with the S/N ratio of 3. The relative standard deviation was 4.2 % for 1.0 × 10−6 mol/L Co (II) ions (n = 8). The most notable features of the detection method are simplicity, rapidity and easy fabrication of the microfluidic chip.