Abstract:

A simple and rapid microfluidic enzymatic reaction method was used to visualize the urea concentration. In the aqueous two-phase system (ATPS), ammonium carbonate produced by the enzymatic reaction discolors the neutral red indicator in droplets, and the color intensity of droplets is analyzed to determine the concentration of urea in the sample to be tested. The detection range can reach 0~50 mg/mL. The microfluidic ATPS droplet flow overcomes the challenge of low biocompatibility of traditional detection platforms based on oil-water droplet. Less consumption, extremely large specific surface area and micro-scale diffusion distance of droplet flow result in the high enzymatic reaction rate. The reaction rate is many times faster than that of traditional beaker method. The detection time is reduced to 20 s. The study aims to provide new ideas and reference for the rapid urea detection in the field of applied chemistry.

Key words: urea detection, microfluidics, aqueous two-phase system, droplet flow, enzymatic reaction