A instrument for measuring solution concentration

In this paper, a set of devices, including hardware and software systems, is designed based on the basic principle of Michelson interferometry to measure solution concentration, enabling real-time online detection. A database is produced by establishing the relationships among the solution concentration, temperature and refractive index. In the subsequent detection procedure, only the solution to be tested is placed into the cuvette, and the relevant parameters are set. The system automatically references the database to determine the solution concentration. The detection time is only approximately 1 min, and the detection efficiency is high. To test the performance of the instruments in this system, we configured solutions with different concentrations and measured the concentration, finding that the resolution of the instrument was 0.1%. We purchased six commercial solutions with different concentrations and compared the reported concentration with the actual concentration. The relative error of the concentration measurement was within 5%, and the relative error of each solution was small. We calculated the relative standard deviation (RSD) for each solution at this concentration, and the RSD of each solution was less than 2%. The results show that the system has high stability and accuracy, and the system is expected to be extended to industrial production, medicine and other fields in the future.