Dissolved oxygen concentration field measurement in micro-scale water flows using PtOEP/PS film sensor

A planar optode system based on an oxygen quenchable luminophore platinum (II) octaethyporphrin (PtOEP) bound with thin polystyrene (PS) film and UV light-emitting diodes (UV-LEDs) was developed to measure the dissolved oxygen (DO) concentration field in micro-scale water flows. An intensity-based method adopting a pixel-to-pixel in situ calibration technique was used to visualize DO concentration fields around an impinging micro-nozzle. The achievable spatial resolution of the acquired concentration map could be as high as 2.94 μm. A micro-round water jet having 100% of DO was obliquely impinged on to a PtOEP/PS film coated plate placed in a 0% of DO water container. Velocity fields were obtained by computational fluid dynamics (CFD) analysis and it is demonstrated that the high DO concentration region was coincided with the impingement area. The DO concentration gradient due to DO diffusion was affected by the Reynolds number.

► A PtOEP/PS film sensor is developed to measure dissolved oxygen (DO) concentration field in micro-scale water flows.
► An intensity-based method adopting a pixel-to-pixel in situ calibration technique is used.
► The spatial resolution of the DO concentration map is 3.0 μm.
► The DO concentration gradient due to DO diffusion is affected by the Reynolds number.