[Method for Simultaneous Quantifying Five Types of Microplastics by Tubular Furnace Pyrolysis-thermal Desorption-gas Chromatography-mass Spectrometry].

Abstract

A susceptible method has been established to simultaneously quantify five types of microplastics greater than 0.22 μm across various environmental matrices, namely, polyethylene （PE）, polypropylene （PP）, polystyrene （PS）, polyvinyl chloride （PVC）, and polyethylene terephthalate （PET）. In detail, five types of microplastics were completely pyrolyzed within a tubular furnace. Pyrolyzates were captured using a Tenax TA absorbent. Subsequently, target compounds were rereleased in a thermal desorption instrument and transferred into gas chromatography/mass spectrometry （GC/MS）. The indicative compounds were filtered and selected to identify and quantify target microplastics. The instrument detection limits for the five types of microplastics ranged from 0.03 μg to 1.91 μg, whereas the method detection limits of target microplastics were 0.07-2.87 μg·L^-1 in water, 0.31-16.52 μg·g^-1 in soil/sediment, and 0.11-7.41 μg·g^-1 in the organism, respectively. The relative standard deviations of 3.31%-22.37%, recoveries of 74.21%-119.63%, and quantitative ranges of 3.7-75 μg for PS； 15-300 μg for PP, PVC, and PET； and 30-600 μg for PE were also implemented. Importantly, this method had simple requirements for sample pretreatment, avoided the interference of complex matrix, and improved the repeatability and reliability of results. Subsequently, the technique quantified target microplastics in water, soil, sediments, and biological tissue. The results showed that the total mass concentrations of five microplastics in water samples were 4.48-37.34 μg·L^-1 and 10.55-218.98 μg·g^-1 in soil and sediments, respectively, and 8.82-19.81 μg·g^-1 in biological samples. This present study provided a reliable technical guarantee for future investigation and monitoring of environmental microplastic pollution.