A portable platform for polyethylene microplastics quantification using an Arduino automatic system

The ubiquitous microplastics (MPs) are serious threaten to human health because of their tiny size, wide distribution and low degradation. Due to their stable physicochemical properties and low cost, plastics are widely used in multiple fields. Consequently, constructing convenient analytical assay for MPs becomes a critical frontier.

In this work, we report a low-cost, portable sensing platform that enables the rapid quantification of polyethylene (PE) MPs in environmental samples. The platform is constructed involving an ultraviolet light-emitting module, a color sensor, a miniaturized liquid crystal display and an Arduino microcontroller, which are integrated into a single 3D-printed box. The "turn-on" yellow fluorescence signal that recorded by color sensor is originated from a staining process between boron-doped carbon dots (B-CDs) and PE MPs via vacuum filtration. Since yellow signal enhances with the mass increase of PE MPs, blue value in RGB is decrease. Linear calibrations are acquired with a mass range of 0.15-1.00 mg and a particle size range of 2-5 μm for PE MPs. Furthermore, the PE content can be programmatically displayed on the liquid crystal display.

A portable fluorescence sensor integrated with an Arduino microcontroller was developed, which can rapidly quantify PE MPs. This solution does not require additional benchtop instrumentations and complex post-processing. The proposed assay is inexpensive, user-friendly and field-deployable, representing a significant step toward portable sensing of MPs.