Progress in quantitative analysis of microplastics in the environment: A review

The amount of plastics released into the environment has been increasing dramatically. As the physical and chemical degradation of plastics results in the production of millimeter- and micrometer-sized plastic particles, their presence has been recognized as an environmental threat. Considerable efforts have been made to identify and quantify microplastics in ecosystems. Millimeter-sized plastic particles can be monitored visually, but confirmation of the type of plastic requires spectroscopic tools such as Fourier-transform infrared spectroscopy, Raman spectroscopy, optical microscopy, and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy. These technologies have long been considered robust methods for the identification of diverse plastic materials, but are not suitable for the quantification of concentrations in the environment using conventional analytical tools. The accuracy of plastic identification also decreases as the size of the particles approaches the scale of a few micrometers. Here, up-to-date technical developments in the identification and quantification of microplastics using pyrolysis–gas chromatography/mass spectrometry (Pyro-GC/MS) are reviewed along with their advantages, disadvantages, and accompanying technical challenges.