A portable UV–vis spectroscopic platform for the detection and quantification of polyethylene microplastics

Microplastics (MPs), particularly polyethylene (PE), represent a growing environmental and public health concern due to their persistence and accumulation in aquatic ecosystems. In this study, a portable, low-cost UV–Vis spectroscopic device was developed for the quantitative detection of PE microplastics in water. The system integrates a UV light source, a 10 mm optical cuvette, optical sensors, and a Raspberry Pi–based data acquisition and control interface. Detection is based on the characteristic absorbance of PE near 234 nm under controlled conditions, with Tween 80 employed as a surfactant to stabilize the MP suspension and enhance measurement reliability. The device was validated under controlled laboratory conditions using PE particles dispersed in deionized (DI) water, with particle sizes ranging from 40 to 100 µm. Excellent linearity was observed (R2 = 0.9761–0.9962), and the calculated limits of detection (LOD) and quantification (LOQ) ranged from 17.63–44.43 ppm and 53.42–134.64 ppm, respectively. Comparative analysis demonstrated close agreement between the proposed device and a commercial spectrometer (SR-6XR250-25). The results indicate that the developed platform provides a reliable and cost-effective approach for laboratory-based quantification of polyethylene microplastics, with potential for future adaptation to complex environmental water matrices and portable monitoring applications.