An effective PDMS microfluidic chip for chemiluminescence detection of cobalt (II) in water

A microfluidic chip for the chemiluminescence detection of cobalt (II) in water samples, based on the measurement of light emitted from the cobalt (II) catalysed oxidation of luminol by hydrogen peroxide in basic aqueous solution, is presented. The microfluidic chip was designed and fabricated from polydimethylsiloxane using micro-molding method. Optimized reagents conditions were found to be 5.0 × 10⁻⁴ mol/L luminol, 1.0 × 10⁻² mol/L hydrogen peroxide, and 8.0 × 10⁻² mol/L sodium hydroxide. The system can perform fully automated detection with a reagent consumption of only 2.4 μL each time. The linear range of the cobalt (II) ions concentration was 1.0 × 10⁻¹⁰–1.0 × 10⁻³ mol/L and the detection limit was 5.6 × 10⁻¹¹ mol/L with the S/N ratio of 3. The relative standard deviation was 4.6 % for 1.0 × 10⁻⁵ mol/L cobalt (II) ions (n = 10).