Optimising sample preparation for FTIR-based microplastic analysis in wastewater and sludge samples: multiple digestions

Abstract

The lack of standardised methodologies in microplastic research has been addressed in recent years as it hampers the comparison of results across studies. The quantification of microplastics in the environment is key to the assessment of the potential eco-toxicological impacts that this new category of emerging pollutants could have on terrestrial and aquatic species. Therefore, the need for protocols that are robust, simple and reliable together with their standardisation are of crucial importance. This study has focused on removal of organic matter with Fenton reagent from wastewater and sludge samples. This step of analysis was optimised by implementing a multi-digestion treatment on these samples that have high concentration of complex mixtures of organic matter, which interfere with microplastic enumeration. Moreover, this study targeted the detection of microplastics in the sub-hundred-micron size range due to the potential higher risks associated with smaller-sized particles and the limited data available from previous wastewater research. To show the validity of the method, triplicate samples of raw sewage, final effluent and sludge were independently spiked with two different sizes and types of microplastic polymers. Due to the various analytical stages required for the isolation of microplastics, time is a limiting factor in sample processing. The sequential digestion with Fenton reagent represents an inexpensive and time-efficient procedure for wastewater research providing effective degradation of organic material. These advantages over other currently available methods mean the method is suitable for analysis of large numbers of samples allowing robust monitoring data sets to be generated.

Efficient extraction of small microplastic particles from rat feed and feces for quantification

“…While a mass loss of <0.5% in bigger particles (1–4 mm) can be considered acceptable for an extraction method, the same is not valid for smaller particles as the surface-to-volume ratio increases with decreasing size, which will lead to increased damage to the chemical integrity of the particle [ 82 ]. The size of the particles used may affect their recovery, also as smaller particles are more likely to adhere to the surfaces of the glass containers and the vacuum filtration unit due to a greater surface charge resulting from their higher surface-to-volume ratio [ 83 ]. To arrive at correct uncertainty estimations and particle losses, recovery studies need to be size and polymer type specific.…”

When microplastics meet electroanalysis: future analytical trends for an emerging threat

“…Several authors have presented new preparation and digestion methods for wastewater and sludge samples that require less preparation time without sacricing quality. [47][48][49] Cunsolo et al 50 proposed a sequential digestion method using Fenton's reagent in samples of wastewaters and nal effluents enriched with PP and PE MPs ($100 mm), reducing the preparation time from 15 to 5 h.…”

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

“…Unfortunately, these methods are not applicable to small MPs and NPs. The solvent extraction method was also applied to extract MNPs from soil samples, ,,,– and PE, PP, PVC, PS, and PET MPs were extracted by dissolving in dichloromethane (DCM). ,,, Nevertheless, the clogging issues of pipelines of the extraction instrument hampered their further application for extraction of solid-embedded MNPs. There is a knowledge and technology gap concerning the detection of NPs and small-sized MPs (<150 μm).…”