TiO2 nanofibers fixed in a microfluidic device for rapid determination of chemical oxygen demand via photoelectrocatalysis

Large arrays of one-dimensional uniform-sized TiO2 nanofibers (TNFs) were prepared through a template-free method, and used as a working electrode in a transparent microfluidic device made from poly (dimethyl siloxane) (PDMS) to perform efficient photoelectrocatalysis for rapid and undefiled determination of chemical oxygen demand (COD). Photoelectrochemical measurements were used to evaluate the response of TNFs to the intensity of exciting light and the applied potential bias. The photoelectrocatalysis of TNFs in PDMS-based microfluidic device exhibited excellent performance for determination of COD. The practical limit of determination of 0.95 mg/L COD with a working range of 0–250 mg/L was achieved. The relative standard deviation (RSD) was 1.85% for 10 repeated measurements of 0.3 mmol/L glucose with COD value of 57.6 mg/L.