Microfluidic chip with interdigitated ultra-microelectrode array for total phosphorus detection

The fabrication and characterisation of an integrated microfluidic chip for phosphate detection are described. A micro three-electrode-system embedded in a microfluidic channel was used for the analysis of samples. Working electrodes and counter electrodes were arranged as an interdigitated array to increase the current response. Owing to the nonlinear diffusion effect of ultra-microelectrodes and the high generation-collection mode of interdigitated electrode arrays, the current density and sensitivity of phosphate detection were improved effectively compared with normal disk microelectrodes. The current density sensitivity for phosphate detection is -0.00537 μA/mm²·(μmol/l)^-1, which is three times that of the disk microelectrode. The current density was averagely 6.5 times that of the disk microelectrode. The microfluidic chip was then used for total phosphorus (TP) detection. The TP detection results showed good consistency with nominal values of standard solutions.