Research on real-time monitoring of total phosphorus in water based on microfluidic optical technology

A microfluidic chip based on optofluidic technology is designed to be used in an online monitoring system for real-time and accurate detection of total phosphorus content in water samples. By designing and preparing a microfluidic chip, the water sample and potassium persulfate solution can fully react in the microfluidic channel, and at the same time, the MnO₂-Au composite film was prepared, so that the light is illuminated inside the microfluidic chip to construct a high temperature and high pressure environment. The total phosphorus digestion process was accelerated, and the absorbance was detected by ammonium molybdate spectrophotometry to calculate the digestion rate. The research results show that under different flow rates and digestion times, four phosphate solutions, including sodium tripolyphosphate, sodium glycerophosphate, sodium pyrophosphate and disodium 5'-guanylate, undergo phosphorus digestion rates inside the microfluidic chip are much faster than on the outside. Then, the four phosphate solutions were mixed in equal proportions to form a total phosphorus mixed water sample, and the digestion comparison between the inside of the microfluidic device and the petri dish respectively showed that the total phosphorus digestion rate inside the microfluidic chip was much higher than that in the petri dish. Phosphorus digestion rate. In the petri dish, the total phosphorus digestion rate can only reach about 38% at 60 minutes, while inside the microfluidic chip, the total phosphorus digestion rate can reach more than 50% under the condition of moderate flow rate.