Sensors for Microplastics Detection in Environmental Matrices

Global concern over microplastics (MPs) has recently prompted several investigations owing to their potential deleterious effects on the environment. Accurate MPs detection with ease and robustness is important for better management decisions to maintain environmental sustainability. The present review summarised advanced sensory techniques for MPs detection in environmental matrices, citing limitations of conventional MPs detection techniques. Bio and synthetic receptors, dyes, nanomaterials, and other materials have been reported for the precise visual detection of MPs through their selective adsorption on different polymer types. Advances techniques like Near Infrared (NIR) and microwave spectroscopy, imaging, light-emitting diodes with photodetectors, electrochemical techniques with microfluidic setups, etc., were also reported for sensing MPs. However, limitations remain in terms of the accurate detection of microplastics with good analytical performance in environmental matrices. The inferior MPs detection limit, found in IR and Raman spectroscopy, could be overcome by hyperspectral imaging spectroscopy with high spatial resolution. Even though these sensing techniques are still in their infancy, the review highlights that sensors for MPs detection are possible and achievable with high accuracy. However, more investigation is required to improve the efficacy of sensing techniques through pinpointing their shortcomings.