Identification of mixed micro- and nanoparticle suspensions using an opto-microfluidic lab-on-a-chip system with Monte Carlo-based light extinction spectrometry

The extinction characteristics of mixed micro- and nanoparticle suspensions with micro-systems are of primary importance in various research fields and industry applications. In this study, light extinction spectrometry on the basis of a Monte Carlo technique is investigated to characterize the mixing ratio and particle radius of monodisperse two-phase suspensions. A series of experimental extinction spectrum measurements for single-phase and two-phase suspensions are operated by an opto-microfluidic lab-on-a-chip system. Subsequently, the optimized genetic algorithm is employed to perform simultaneous inversion of the mixing ratio and radius for two-phase suspensions based on spectral measurements. The results indicate that the inversion errors are < 2 % and < 5 % for single-parameter and multi-parameters of mixed particle suspensions, respectively. It clearly demonstrates the value of the proposed system for simultaneously identifying particle radii and mixing ratio in mixed particle suspension. These findings confirm the effectiveness of our system, which can be used as a mixed particle identification platform for advanced applications such as medical diagnosis and environmental monitoring. It can also be further extended to handle polydisperse and non-spherical particle suspensions for more complex and realistic scenarios.