Identification and Quantification of Micro-Bioplastics in Environmental Samples by Pyrolysis–Gas Chromatography–Mass Spectrometry

Abstract

Bioplastics are materials that are biobased and/or biodegradable, but not necessarily both. Concerns about environmental plastic pollution are constantly growing with increasing demand for substituting fossil-based plastics with those made using renewable resource feedstocks. For many conventional bioplastics to completely decompose/degrade, they require specific environmental conditions that are rarely met in natural ecosystems, leading to rapid formation of micro-bioplastics. As global bioplastic production and consumption/use continue to increase, there is growing concern regarding the potential for environmental pollution from micro-bioplastics. However, the actual extent of their environmental occurrence and potential impacts remains unclear, and there is insufficient mass concentration-based quantitative data due to the lack of quantitative analytical methods. This study developed and validated an analytical method coupling pressurized liquid extraction and pyrolysis–gas chromatography–mass spectrometry combined with thermochemolysis to simultaneously identify and quantify five targeted micro-bioplastics (i.e., polylactic acid (PLA), polyhydroxyalkanoate, polybutylene succinate, polycaprolactone, and polybutylene adipate terephthalate (PBAT)) in environmental samples on a polymer-specific mass-based concentration. The recovery of spiked micro-bioplastics in environmental samples (biosolids) ranged from 74 to 116%. The limits of quantification for the target micro-bioplastics were between 0.02 and 0.05 mg/g. PLA and PBAT were commonly detected in wastewater, biosolids, and sediment samples at concentrations between 0.07 and 0.18 mg/g. The presented analytical method enables the accurate identification, quantification, and monitoring of micro-bioplastics in environmental samples. This study quantified five micro-bioplastic types in complex environmental samples for the first time, filling in gaps in our knowledge about bioplastic pollution and providing a useful methodology and important reference data for future research.

A thermoanalytical insight into the composition of biodegradable polymers and commercial products by EGA-MS and Py-GC-MS

“…The results obtained from EGA-MS and Py-GC-MS analyses of the biodegradable polymers of reference are summarized in Table 3. Recently, Okoffo et al analysed PLA, PBAT, PBS and PHBV by reactive Py-GC-MS adding tetramethylammonium hydroxide for thermally assisted hydrolysis and methylation (TMAH) [51].…”

“…Compared to other thermal techniques like thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC), Py-GC-MS allows identification of thermal degradation products and therefore makes it possible reconstructing the structure and composition of the material analysed [39]. To this end, previous studies have applied Py-GC-MS to characterise biodegradable polymers including PLA [40]- [46], PHBV [5], [47], [48], PBS [45], [49] and PBAT [50], [51], PLA-labelled shampoo bottles [52], PLA cups and PLA/PBAT compostable plastic bags [53]. However, a systematic and thoroughly thermoanalytical investigation of biodegradable polymers with consistent Py-GC-MS methodology has yet to be conducted.…”

Biodegradable Microplastics in Municipal Wastewater and Sludge Treatment Processes: A Review on Occurrence, Fate, and Effects

“…These cities were situated across various regions of Australia. 33,46,47 Notably, the concentration of BMPs in sludge was significantly lower than that of widely employed conventional microplastics (such as PE, PVC, PET, etc.) (Figures 2a and 2b).…”

“…Scanning electron microscopy (SEM) and spectral analysis techniques were widely used to identify microplastics, of which spectral analysis included attenuated total reflection–Fourier transform infrared spectroscopy (ATR-FTIR), , Raman spectroscopy, X-ray diffraction (XRD), etc. For quantitative analysis, thermal analysis methods were commonly used, including techniques such as differential scanning calorimetry (DSC), pyrolysis-gas chromatography–mass spectrometry (Pyro-GC/MS), and thermal extraction desorption-gas chromatography–mass spectrometry (TED-GC/MS) . The generic analytical approaches listed above have been thoroughly summarized in other reviews. − This review primarily focuses on the differences and challenges in BMP analysis.…”

Innovative Bioplasticizers from Residual Cynara cardunculus L. Biomass-Derived Levulinic Acid and Their Environmental Impact Assessment by LCA Methodology

“…However, biodegradable biobased plastics and additives are not devoid of even significant environmental impacts. , Therefore, the risk potentially associated with the production and use of these biomaterials to simply shift the environmental impacts to a different phase of their life cycle must be avoided. For this reason, the application of LCA (Life Cycle Assessment) methodology was recognized as imperative to reach clear evidence of their higher environmental sustainability with respect to petrochemical alternatives …”