Microplastics, an emerging concern: A review of analytical techniques for detecting and quantifying microplastics

Abstract

Microplastics are ubiquitous tiny plastic particles (< 5 mm) nonbiodegradable and have large surface area in the environment or the body of living things due to anthropogenic activities or fragmentation of plastic debris. Though they have been found in sea food and human body, their health implications are still speculative. Moreover, a major reason for dearth of information on this topical issue is the lack of standard operating protocol for detecting and quantifying microplastics as a result of their presence in more complex environmental matrices. In the present review some methodologies for analyzing microplastics reported in the period 2000 to 2018 have been documented with the aim of assessing which methods is most suitable and in what matrix. The following methods have been studied: CHN analyzers, pyrolysis-gas chromatography/mass spectroscopy (PyrGC/MS), optical microscopy, fourier transform infrared microspectroscopy (Micro-FTIR), raman microspectroscopy (RMS) and scanning electron microscopy with energy dispersive x-ray spectroscopy (SEM-EDS), effective for particles <500 μm. However, the quality of result obtained strongly relies on good sampling and sample purification. Specifically, Micro- Raman spectroscopy is best for particles of <1 μm while degradation process of plastics is best monitored with SEM-EDS. Generally, studies have been conducted with often a combination of two methods: One separating and the other quantifying which can be problematic moreso in living tissue where there is no harm reported as at the time of this study. Ultimately based on this study, microplastics have become a cause for concern and advance studies are required to unravel the potential risk of their presence in our food and environment.