Systematic development of extraction methods for quantitative microplastics analysis in soils using metal-doped plastics

Effect of Polymer Properties on the Biodegradation of Polyurethane Microplastics

“…To achieve monolayers on the filters, 16 filters needed to be prepared and analyzed for several days (Figure S4). FTIR microscopy confirmed the recovery of 16 out of 20 particles (≙ 80%) in this trace analysis test, which is comparable to recoveries reported in the literature (where such trace analysis is not routine). , According to our results (>2000 particles/gram compost), no trace analysis was needed here. Doubly extracted sample: Recovery and stability tests in the literature are usually performed with pristine microplastic particles. ,, While this provides important insights, it is not necessarily representative for aged or partially biodegraded particles. This test served to detect substantial losses of aged particles during extraction but does not provide information on the loss of a specific size fraction.…”

“…55 wt % CaCl 2 was chosen for the density separation and washing steps after ultrasonication and sieving to achieve a high density of 1.5 g/cm 3 , making this protocol suitable for a large range of common microplastic types, even for those with high densities. , With CaCl 2 , strong alkalinity or acidity is avoided, since pH for the used concentration is around 6 (compared to, e.g., the commonly used acidic ZnCl 2 with pH < 1 and sodium polytungstate with pH < 4.5). , Additional controls on the surface texture (Figure b) and chemistry (Figure c) proved the advantage of the chosen mild conditions, having no impact on the polymer properties. In contrast to extraction methods reported in the literature, we explicitly focused on the mild extraction conditions to avoid changes in the particle properties, thus avoiding the use of oxidation reagents, which we considered as one of the harshest chemical treatments for microplastic extraction. ,, …”

“…Doubly extracted sample: Recovery and stability tests in the literature are usually performed with pristine microplastic particles. ,, While this provides important insights, it is not necessarily representative for aged or partially biodegraded particles. This test served to detect substantial losses of aged particles during extraction but does not provide information on the loss of a specific size fraction.…”

“…In contrast to extraction methods reported in the literature, we explicitly focused on the mild extraction conditions to avoid changes in the particle properties, thus avoiding the use of oxidation reagents, which we considered as one of the harshest chemical treatments for microplastic extraction. 41,57,58 The extraction was validated with several complementary controls and recovery tests. The washing step with density separation was identified to be the most critical step, in which particle losses might occur.…”

Effect of Growth Media on the Diversity of Neocallimastigomycetes from Non-Rumen Habitats

“…The Neocallimastix frontalis strain GBF20D4 cultivated in all three media was used as a positive control in this study. The strain was isolated at ZHAW from Chamois ( Rupicapra rupicapra ) feces using DRF medium [ 35 ]. Negative controls were composed of uninoculated media bottles processed under the same conditions.…”