Extraction of Common Small Microplastics and Nanoplastics Embedded in Environmental Solid Matrices by Tetramethylammonium Hydroxide Digestion and Dichloromethane Dissolution for Py-GC-MS Determination

Abstract

Determination of microplastics and nanoplastics (MNPs), especially small MPs and NPs (<150 μm), in solid environmental matrices is a challenging task due to the formation of stable aggregates between MNPs and natural colloids. Herein, a novel method for extracting small MPs and NPs embedded in soils/sediments/sludges has been developed by combining tetramethylammonium hydroxide (TMAH) digestion with dichloromethane (DCM) dissolution. The solid samples were digested with TMAH, and the collected precipitate was washed with anhydrous ethanol to eliminate the natural organic matter. Then, the MNPs in precipitate were extracted by dissolving in DCM under ultrasonic conditions. Under the optimized digestion and extraction conditions, the factors including sizes and concentrations of MNPs showed insignificant effects on the extraction process. The feasibility of this sample preparation method was verified by the satisfactory spiked recoveries (79.6−91.4%) of polystyrene, polyethylene, polypropylene, poly(methyl methacrylate), polyvinyl chloride, and polyethylene terephthalate MNPs in soil/sediment/sludge samples. The proposed sample preparation method was coupled with pyrolysis gas chromatography−mass spectrometry to determine trace small MPs and NPs with a relatively low detection limit of 2.3−29.2 μg/g. Notably, commonly used MNPs were successfully detected at levels of 4.6−51.4 μg/g in 6 soil/sediment/sludge samples. This proposed method is promising for evaluating small solid-embedded MNP pollution.

The power of centrifugation: How to extract microplastics from soil with high recovery and matrix removal efficiency

“…The results for the mass-based analysis are shown in Fig. 5 a: For all the soils tested the microplastic recovery was higher than 90 wt.-%, which is in the upper range of recoveries commonly reported in literature [6] , [7] , [8] . The results for the counting approach are shown in Fig.…”

Micro(nano)plastics in the Human Body: Sources, Occurrences, Fates, and Health Risks

“…Nevertheless, the possibility that these MNPs may release toxic substances into the body prior to removal must be considered since MNPs are mixtures rather than simple compounds. Since only <20 studies have examined the occurrence of MNPs in human samples, , the actual contents of MNPs in human samples remain insufficiently understood, with further studies impeded by the lack of suitable analytical methods. Furthermore, current studies mainly focus on MNPs sized >1 μm in human samples, with limited studies examining the presence of more toxic NPs.…”

“…However, current data evaluations underestimate the actual quantity of MNPs entering the human body since they consider only a few exposure routes and exclude NPs. Although NPs have recently been detected in seafood, water, soil, and air, − their induced human consumption remains unclear. Thus, the real quantities of MNPs consumed by humans remain unknown, and the human consumption of MNPs, including NPs, must be comprehensively evaluated.…”

Water Analysis: Emerging Contaminants and Current Issues

“…A new method for extracting MPs and NPs embedded in solid environmental matrices was created by Li et al 245 This method involves tetramethylammonium hydroxide digestion, followed by washing with ethanol to eliminate NOM, and dissolution with dichloromethane and ultrasonication. Recoveries of 80−91% were achieved for polystyrene, polyethylene, polypropylene, poly(methylmetharylate), PVC, and polyethylene terephthalate MPs and NPs in soil, sediment, and sludge samples.…”