Recent perspectives of microplastic analysis from sampling to characterization

Abstract

Microplastic (MP) pollution has been an emerging global concern due to its persistent nature and the requirement for sophisticated detection techniques. However, MP research has always been complexified due to the unavailability of structured methodology and the ambiguity of process selection. This review has critically analyzed different aspects of MP abundance in water, sediments, biota and wastewater and MP analyzing techniques. MP analysis results are solely dependent on its processing stages, such as oven drying and sieving, chemical digestion, and alkaline treatment, which are the crucial parts of MP sample preparation and processing. To identify the specified polymer in MP samples, analytical techniques such as Fourier transform infrared Spectroscopy (FTIR), Raman spectra (RS), and pyrolysis-gas chromatography-mass spectrometry (Pyr GC-MS) are widely used. Among the applied techniques, FTIR is the cheapest, whereas µ-RS is the most accurate. MP matrix specifications and concentrations vary for water, sediments, biota, and wastewater sources. The highest concentration of 152,688 ± 92,384 particles/m³ MP was observed for the Sea Surface Microlayer of 1000 µm. The MPs concentration in river water reached 718 ± 244 MPs/m³. River sediments of developing countries like Bangladesh, Indonesia and Taiwan have very high concentrations of MPs, which is a great concern for river biota. Various types of plastics, including PP, PE, PE-PP, PE-PDM, PET, nylon, T-elastomer, CP, wool, and cotton, were identified in reported studies. The study discloses recent perspectives on MP research and appropriate sampling and analysis techniques are crucial for reporting MPs in environmental samples.