A portable instrument for intelligent analysis of low-abundance groundwater microplastics with...

Microplastic pollution in groundwater has become one of the most challenging environmental issues. However, there is a lack of portable instruments for on-site detection of low-abundance microplastics. To address this, we developed a portable instrument for intelligent analysis of low-abundance microplastics in groundwater by integrating the dielectrophoretic (DEP) assembly of a four-phase rotating electric field with an object detection framework based on YOLO26. Firstly, a microfluidic chip was designed and fabricated to construct a portable instrument for rapid assembly, and an object detection model was developed to identify microplastics with diverse sizes, shapes, and colors. Secondly, a computational model was established to theoretically investigate the phase-dependent variation in the electric field and the microplastic assembly by analyzing particle velocities and trajectories. The feasibility of this portable instrument was demonstrated using polystyrene microplastics, which was consistent with the numerical simulations. Thirdly, the assembly performance of the chip was explored for microplastics of different polymer types, and the voltage-amplitude and solution-conductivity dependencies of microplastics assembly were systematically characterized. Depending on these, we used this portable instrument to achieve the intelligent analysis of spherical microplastics, including the size and abundance. Finally, the portable instrument was engineered for the detection of low-concentration microplastics in groundwater to rapidly acquire the size and abundance of microplastics with irregular shapes. This instrument can realize rapid assembly and intelligent analysis of low-concentration microplastics in groundwater and holds great potential in the guarantee of the drinking-water safety with advantages of intelligence, portability, and multiparametricity.