Large Sample Volumes Research Articles

A universal electrochemical-modulated surface-enhanced Raman scattering platform for the sensitive detection of charged molecules

Electrochemical-modulated surface-enhanced Raman scattering (EC-SERS) integrates the benefits of SERS with electrochemical techniques. By controlling the electrode potential, Raman spectroscopy allows for the analysis of molecules with enhanced sensitivity and selectivity. With its large volume and high sample consumption, the traditional three-electrode electrochemical cell constrains the widespread adoption of EC-SERS. This study developed a versatile EC-SERS platform based on Ag nanowires-modified screen-printed electrode (AgNWs-SPE). Taking advantage of the dual functionality of AgNWs-SPE, this platform facilitates the successful in situ collection and sensitive detection of charged molecules. Experimental findings and theoretical calculations validate the platform's high sensitivity and selectivity mainly regulated by the applied potential, providing a universal approach for the highly sensitive and accurate detection of charged molecules.

Combination of on-line sample preconcentration by large-volume dual preconcentration by isotachophoresis and stacking (LDIS) with field-amplified sample injection (FASI) on Y-channel microchips.

In our previous study, the combination of two on-line sample preconcentration techniques, large-volume sample stacking with an electroosmotic flow (EOF) pump (LVSEP) and transient isotachophoresis (tITP), in microchip electrophoresis (MCE) was developed, which was named large-volume dual preconcentration by isotachophoresis and stacking (LDIS). LDIS was apparently effective for improving the sensitivity and the peak shape. In LDIS, however, there was a limit to the improvement of the sensitivity enhancement factor (SEF) since the amount of analytes to be concentrated was limited to the channel volume. To overcome this issue, in the present article, LDIS was coupled with field-amplified sample injection (FASI) technique on Y-shaped channel microchips. The use of a Y-channel in LDIS-FASI allowed consecutive LVSEP, FASI and tITP enrichments with a simple voltage control. In conventional LVSEP and LDIS analyses of a standard analyte, the SEFs were evaluated to be 2630 and 13,100, respectively, whereas in LDIS-FASI that was increased to 27,900 even at the FASI injection time of 0s. To achieve higher SEFs, furthermore, the FASI injection time was increased to 150s, resulting in the best SEF of 58,500. It should be emphasized that the peak width in LDIS-FASI was quite narrow, only 0.3-3.1s, while in normal LVSEP that was 13s. Furthermore, the LDIS-FASI technique was applied to the analysis of oligosaccharide mixture. Due to the focusing effect by LDIS-FASI, the resolutions were improved from 0.97-1.57 to 2.08-2.73.

Characterization of solid wastes from sablefish (Anoplopoma fimbria) in intensive culture

Sablefish (Anoplopoma fimbria) is a Pacific marine species that adapts well to aquaculture, grows extremely fast, and command a high market price. Because of environmental and regulatory concerns, increased production of this species is likely to occur in land-based systems. Little is known about the waste production characteristics of sablefish, information that will have a critical impact on the design of aeration, solid removal, and biofilter design for this species. It was found that the concentration of total suspended solids (TSS) in the effluent was extremely low and the mean TSS ranged from 0.9 to 1.7 mg/L. Compared to other important culture fish, sablefish produce significantly less fecal solids (5.2–7.9 % based on feed inputs) and less of their solids settled out (57.3–65.8 % of total suspended solids). TSS production following feeding of a special feed for reuse systems was significantly higher (51.9 %) compared to fish fed a conventional diet. The reduced production of TSS by sablefish is due to higher apparent digestibility coefficients and possible production of wastes that are not retained on the standard filter used for TSS analysis. Additional rinsing of the filters to remove salt and the use of large sampling volumes can significantly improve the accuracy of TSS analysis for marine culture species.

Portable point-of-care surface enhanced Raman scattering spectroscopy for the quantification of glutathione in whole blood microsamples

Glutathione (GSH) is a non-protein tripeptide thiol that plays a prominent role in oxidative stress defense. GSH concentration is particularly critical in the neonatal period, especially for premature newborns that face increased susceptibility to oxidative stress. Monitoring GSH levels provides valuable insights into newborn health, helping to tailor care to their specific needs. The aim of this study was the development of a sensor specifically targeted for its use in neonatology, enabling GSH determination in only 2 μL of whole blood. The newly developed sensing system simplifies sample processing, addressing a critical need in clinical applications. Unlike current methods that demand fast pre-processing of relatively large sample volumes, expensive equipment, and skilled personnel, the developed approach streamlines the analytical process. By using 2 μL of whole blood, a single syringe filter for sample treatment, a deuterated internal standard (IS) for signal normalization, and Surface Enhanced Raman Scattering (SERS) spectroscopy with a silver colloid substrate for GSH detection, the set-up's characteristics are compatible with point-of-care applications. The analytical procedure was validated and applied to diverse populations including healthy adults (N = 63) and newborns (N = 35), yielding GSH concentration values ranging from 0.6 to 1.8 and 0.8–2.1 mM, respectively. This new optical sensor offers a quick and cost-effective solution to support the assessment of GSH levels in newborns that can greatly benefit not only neonatal care, but also the study of adult populations for health monitoring.

Rapid isolation method for extracellular vesicles based on Fe3O4@ZrO2.

Extracellular vesicles (EVs) are pivotal in intercellular communication, disease mechanisms. Despite numerous methods for EVs isolation, challenges persist in yield, purity, reproducibility, cost, time, and automation. We introduce a EVs isolation technique using Fe3O4@ZrO2 beads, leveraging ZrO2-phosphate interaction. The results indicated that EVs were efficiently separated from large volumes of samples in 30minutes without preconcentration. Our method demonstrated capture efficiency (74%-78%) compared to ultracentrifugation, purity (97%), and reproducibility (0.3%-0.5%), with excellent linearity (R2 > 0.99). EVs from urine samples showed altered expression of miRNAs. The logistic regression model achieved an AUC of 0.961, sensitivity of 0.92, and specificity of 0.94. With potential for automation, this magnetic bead-based method holds promise for clinical applications, offering an efficient and reliable tool for EVs research and clinical studies.

Discovery and Identification of Three Homocysteine Metabolites by Chemical Derivatization and Mass Spectrometry Fragmentation.

Discovery and identification of a new endogenous metabolite are typically hindered by requirements of large sample volumes and multistage purifications to guide synthesis of the standard. Presented here is a metabolomics platform that uses chemical tagging and tandem mass spectrometry to determine structure, direct synthesis, and confirm identity. Three new homocysteine metabolites are reported: N-succinyl homocysteine, 2-methyl-1,3-thiazinane-4-carboxylic acid (MTCA), and homolanthinone.

Stabilizing and Accelerating Secondary Flow in Ultralong Spiral Channel for High-Throughput Cell Manipulation.

Efficient cell manipulation is essential for numerous applications in bioanalysis and medical diagnosis. However, the lack of stability and strength in the secondary flow, coupled with the narrow range of practical throughput, severely restricts the diverse applications. Herein, we present an innovative inertial microfluidic device that employs a spiral channel for high-throughput cell manipulation. Our investigation demonstrates that the regulation of Dean-like secondary flow in the microchannel can be achieved through geometric confinement. Introducing ordered microstructures into the ultralong spiral channel (>90 cm) stabilizes and accelerates the secondary flow among different loops. Consequently, effective manipulation of blood cells within a wide cell throughput range (1.73 × 108 to 1.16 × 109 cells/min) and cancer cells across a broad throughput range (0.5 × 106 to 5 × 107 cells/min) can be achieved. In comparison to previously reported technologies, our engineering approach of stabilizing and accelerating secondary flow offers specific performance for cell manipulation under a wide range of high-throughput manner. This engineered spiral channel would be promising in biomedical analysis, especially when cells need to be focused efficiently on large-volume liquid samples.

A rapid and multi-endpoint ecotoxicological test using Mychonastes afer for efficient screening of metals and herbicides

Microalgal growth-based tests are international standards for ecotoxicity assessment; however, their long exposure times, large sample volumes, and reliance on a single growth-endpoint make them inadequate for rapid toxicity screening. Here, we aimed to develop a rapid and simple ecotoxicological test using the fast-growing green alga Mychonastes afer, with multiple endpoints—growth, lipid content, and photosynthesis. We exposed M. afer to two metals—silver and copper—and two herbicides—atrazine and diuron—for 24 h and identified the most sensitive and reliable endpoints for each toxicant: the maximum electron transport rate (ETRmax) for Ag, Cu and atrazine, and the lipid content for diuron. Lipid content was found to be both a sensitive and reliable biomarker, meeting the effluent limit guidelines in both the Republic of Korea and the USA. The sensitivity of M. afer to Ag and atrazine also closely matched the HC5 values derived from the species sensitivity distribution approach, confirming its reliability for setting regulatory concentrations of these contaminants. Our calculated predicted no-effect concentration (PNEC) values were similar to established European Union PNECs for Ag, Cu, atrazine, and diuron, underlining the utility of these biological endpoints for ecological risk assessment and regulatory decision making. This method required lower sample volume (2 mL vs 100 mL) and exposure time (24 h vs 72–120 h) than conventional green algal tests, and eliminated the need for labour-intensive cell counting, expensive equipment, and chlorophyll fluorescence measurement expertise. Overall, this M. afer test can be a valuable tool for the rapid screening of wastewater for metals and herbicides, contributing to environmental protection and management practices.

A Compact Differential Dynamic Microscopy-based Device (cDDM): An Approach Tool for Early Detection of Hypercoagulable State in Transfusion-Dependent-β-Thalassemia Patients.

β-Thalassemia especially transfusion-dependent thalassemia (TDT) associates with a hypercoagulable state, which is the main cause of thromboembolic events (TEE). Plasma viscosity and rheological parameters could be essential markers for determining hypercoagulable state in β-thalassemia patients. The traditional methods for measuring viscosity are often limited by large sample volumes and are impractical for routine clinical monitoring. The compact differential dynamic microscopy-based device (cDDM), an optical microscopy for quantitative rheological assessment, was developed and applied for prognosis of the hypercoagulable state in β-TDT with and without splenectomy. The device was performed plasma viscosity measurement using low plasma volume (8 μL) and revealed a value as modulus of complex viscosity |η(ω)| in 7 min. We also parallelly demonstrated the correlation of the viscosity and related-coagulable parameters: complete blood count, prothrombin time (PT), activated partial thromboplastin time (APTT), protein C (PC), protein S (PS), CD62P and CD63 expression, and platelet aggregation test. The thalassemia plasma exhibited a higher value of |η(ω)| than healthy plasma, which can represent a different viscoelastic property among the groups. Even all related-coagulable parameters indicated hypercoagulable state in both nonsplenectomies and splenectomies β-TDT patients when compared to control, only high platelet numbers significantly correlated to high plasma viscosity in the splenectomy group. However, the other coagulable parameters have shown a trend of positive relationship with high plasma viscosity in all β-1thalassemia TDT patients. The relative results suggested that our device would be an approach tool for early detection of hypercoagulable state in transfusion-dependent-β-thalassemia patients, which can help to prevent TEE and the critical consequent-complications.

Investigation of on-line electrokinetic enrichment strategies for capillary electrophoresis of extracellular vesicles

This work explores strategies for electrokinetic preconcentration of extracellular vesicles (EVs) that are potential source of biomarkers for different diseases. The first approach that led to successful preconcentration of EVs is based on large volume sample stacking (LVSS), allowing an enrichment factor of 7 for CE of EVs with long-end injection (using a capillary with an effective length of 50 cm). Attempts were also made to perform multiple cycles of LVSS, field amplified sample stacking (FASS) and field amplified sample injection (FASI), to improve EVs preconcentration performance. The focus was then put on development of capillary isotachophoresis under high ionic strengths (IS) for electrokinetic enrichment of slow migrating EVs having heterogeneous mobilities. This approach relies on the use of extremely high concentrations of the terminating electrolyte (TE) to slow down the mobility of TE co-ions, rendering them slower than those of EVs. The limit of detection for intact EVs using the developed ITP-UV method reached 8.3 × 108 EVs/mL, allowing an enrichment of 25 folds and a linear calibration up to 4 × 1010 EVs/mL. The ITP-UV and ITP-LIF approaches were applied to provide the electrokinetic signature of EVs of bovine milk and human plasma as well as to visualize more specifically intravesicular fluorescently labelled EVs. The investigation of these strategies shredded light into the challenges still encountered with electrokinetic preconcentration and separation of heterogeneous EVs sub-populations which are discussed herein based on our results and other attempts reported in the literature.

Effects of time of the day at sampling on CSF and plasma levels of Alzheimer’ disease biomarkers

BackgroundStudies suggest that cerebrospinal fluid (CSF) levels of amyloid-β (Aβ)42 and Aβ40 present a circadian rhythm. However sustained sampling of large volumes of CSF with indwelling intrathecal catheters used in most of these studies might have affected CSF dynamics and thereby confounded the observed fluctuations in the biomarker levels.MethodsWe included 38 individuals with either normal (N = 20) or abnormal (N = 18) CSF Aβ42/Aβ40 levels at baseline. CSF and plasma were collected at two visits separated by an average of 53 days with lumbar punctures and venipunctures performed either in the morning or evening. At the first visit, sample collection was performed in the morning for 17 participants and the order was reversed for the remaining 21 participants. CSF and plasma samples were analyzed for Alzheimer’ disease (AD) biomarkers, including Aβ42, Aβ40, GFAP, NfL p-tau181, p-tau217, p-tau231 and t-tau. CSF samples were also tested using mass spectrometry for 22 synaptic and endo-lysosomal proteins.ResultsCSF Aβ42 (mean difference [MD], 0.21 ng/mL; p = 0.038), CSF Aβ40 (MD, 1.85 ng/mL; p < 0.001), plasma Aβ42 (MD, 1.65 pg/mL; p = 0.002) and plasma Aβ40 (MD, 0.01 ng/mL, p = 0.002) were increased by 4.2-17.0% in evening compared with morning samples. Further, CSF levels of 14 synaptic and endo-lysosomal proteins, including neurogranin and neuronal pentraxin-1, were increased by 4.5-13.3% in the evening samples (MDrange, 0.02-0.56 fmol/µl; p < 0.042). However, no significant differences were found between morning and evening levels for the Aβ42/Aβ40 ratio, different p-tau variants, GFAP and NfL. There were no significant interaction between sampling time and Aβ status for any of the biomarkers, except that CSF t-tau was increased (by 5.74%) in the evening samples compared to the morning samples in Aβ-positive (MD, 16.46 ng/ml; p = 0.009) but not Aβ-negative participants (MD, 1.89 ng/ml; p = 0.47). There were no significant interactions between sampling time and order in which samples were obtained.DiscussionOur findings provide evidence for diurnal fluctuations in Aβ peptide levels, both in CSF and plasma, while CSF and plasma p-tau, GFAP and NfL were unaffected. Importantly, Aβ42/Aβ40 ratio remained unaltered, suggesting that it is more suitable for implementation in clinical workup than individual Aβ peptides. Additionally, we show that CSF levels of many synaptic and endo-lysosomal proteins presented a diurnal rhythm, implying a build-up of neuronal activity markers during the day. These results will guide the development of unified sample collection procedures to avoid effects of diurnal variation for future implementation of AD biomarkers in clinical practice and drug trials.

Data oversampling and feature selection for class imbalanced datasets

Introduction: Significant advancements and modifications have been implemented in data classification (DC) in the past few decades. Due to their infinite quantity and imbalance, data becomes challenging for classification. The biggest concern in DM (Data Mining) is Class Imbalance (CI). To avoid these issues in recent work proposed map reduce based data parallelization of class imbalanced datasets. Methods: A novel Over Sampling (OS) technique called Minority Oversampling in Kernel Canonical Correlation Adaptive Subspaces (MOKCCAS) has been suggested with the objective to minimize data loss throughout (FSP) Feature Space Projections. This technique takes advantage of the constant Feature Extraction (FE) capability of a version of the ASSOM (Adaptive Subspace Self-Organizing Maps) that is derived from Kernel Canonical Correlation Analysis (KCCA). And in classification, Feature Selection (FS) plays an important role because the acquired dataset might contain large volume of samples, utilizing all features of samples from the dataset for classification will decrease the classifier performance. And then data parallelization will be done by using map reduce framework to solve this computation requirement problem.Result: Then proposes a feature selection model using Mutated whale optimization (MWO) methods and produces features and reduces the time consumption. Finally proposed class balancing model will be tested using uniform distribution based enhanced adaptive neuro fuzzy inference system (UDANFIS). Test outcomes validate the efficiency of the suggested technique by precision, recall, accuracy and Error Rate (ER).Conclusion: The study subsequently suggests a novel OS approach called MOKCCAS to lessen the loss of data throughout feature space projection.

A novel solid-phase extraction device for the pneumatic cycle pharmaceuticals residues adsorption: A proof of concept study

In this study, a pneumatic cycle device, herein called the air-operated solid-phase extraction (AO-SPE), was designed for the enrichment of pharmaceutical residues. The device consisted of two parts: an air circulation system and an adsorption system. The continuous air flow ensured that the water sample flowed past the adsorbent, completing the adsorption process. One significant advantage of this device is that the air circulation system can generate pneumatic cycle adsorption with the continuous air flow, increasing the interaction between the adsorbent and the target analytes. Additionally, the entire device is easy to install and dismantle, and the adsorbent can be easily replaced, making the AO-SPE suitable for various types of adsorbents materials tailored to specific target analytes. The smart design is aimed at extracting trace analytes in the large-volume water samples. As a proof-of-concept, the AO-SPE was applied to enrich non-steroidal anti-inflammatory drugs in soil. A Ce-based metal organic framework composite was prepared and applied to verify the applicability of AO-SPE, exhibiting the enrichment factor of up to 538. The results showed that AO-SPE exhibited a maneuverable approach with high efficiency and sensitivity for analyzing large-volume samples, indicating a great potential for extracting of trace analytes.

Development, synthesis, and application of magnetic layered double hydroxides (Fe3O4@SiO-LDH/DS−) as an efficient adsorbent for the removal of tetracyclines from milk samples

This work presents the development, synthesis, and application of a layered double hydroxide (LDH) coupled to magnetic particles for the removal of antibiotics as tetracyclines (TC´s): tetracycline (TC), chlortetracycline (CT), oxytetracycline (OT), and doxycycline (DT) from milk samples. The LDH synthesis conditions, reaction time (30–90 min), molar ratios Mg2+/Al3+ (7:1–1:7), interlayer anion (NO3−, Cl−, CO32−, and dodecyl sulphate (DS−)) were evaluated. Under synthesis conditions (reaction time of 30 min, Mg2+/Al3+ molar ratio of 7:1, and DS− as interlayer anion), the LDH was coupled in a magnetic solid phase microextraction (MSPμE) methodology. At the optimal extraction conditions (pH 6, 5 min of contact time, 10 mg of adsorbent), a removal percentage of 99.0 % was obtained for each tetracycline. FTIR, TGA, SEM, and adsorption isotherms were employed to characterize the optimal adsorbent. Each experiment was corroborated by large-volume sample stacking capillary electrophoresis (LVSS-CE). The adsorbent was applied directly to positive milk samples (previously tested) for TC´s removal.

EchoGrid: High-Throughput Acoustic Trapping for Enrichment of Environmental Microplastics.

The health hazards of micro- and nanoplastic contaminants in drinking water has recently emerged as an area of concern to policy makers and industry. Plastic contaminants range in size from micro- (5 mm to 1 μm) to nanoplastics (<1 μm). Microfluidics provides many tools for particle manipulation at the microscale, particularly in diagnostics and biomedicine, but has in general a limited capacity to process large volumes. Drinking water and environmental samples with low-level contamination of microplastics require processing of deciliter to liter sample volumes to achieve statistically relevant particle counts. Here, we introduce the EchoGrid, an acoustofluidics device for high throughput continuous flow particle enrichment into a robust array of particle clusters. The EchoGrid takes advantage of highly efficient particle capture through the integration of a micropatterned transducer for surface displacement-based acoustic trapping in a glass and polymer microchannel. Silica seed particles were used as anchor particles to improve capture performance at low particle concentrations and high flow rates. The device was able to maintain the silica grids at a flow rate of 50 mL/min. In terms of enrichment, the device is able to double the final pellet's microplastic concentration every 78 s for 23 μm particles and every 51 s for 10 μm particles at a flow rate of 5 mL/min. In conclusion, we demonstrate the usefulness of the EchoGrid by capturing microplastics in challenging conditions, such as large sample volumes with low microparticle concentrations, without sacrificing the potential of integration with downstream analysis for environmental monitoring.

Efficient SARS-CoV-2 variant detection and monitoring with Spike Screen next-generation sequencing.

The emergence and rapid spread of SARS-CoV-2 prompted the global community to identify innovative approaches to diagnose infection and sequence the viral genome because at several points in the pandemic positive case numbers exceeded the laboratory capacity to characterize sufficient samples to adequately respond to the spread of emerging variants. From week 10, 2020, to week 13, 2023, Slovenian routine complete genome sequencing (CGS) surveillance network yielded 41537 complete genomes and revealed a typical molecular epidemiology with early lineages gradually being replaced by Alpha, Delta, and finally Omicron. We developed a targeted next-generation sequencing based variant surveillance strategy dubbed Spike Screen through sample pooling and selective SARS-CoV-2 spike gene amplification in conjunction with CGS of individual cases to increase throughput and cost-effectiveness. Spike Screen identifies variant of concern (VOC) and variant of interest (VOI) signature mutations, analyses their frequencies in sample pools, and calculates the number of VOCs/VOIs at the population level. The strategy was successfully applied for detection of specific VOC/VOI mutations prior to their confirmation by CGS. Spike Screen complemented CGS efforts with an additional 22897 samples sequenced in two time periods: between week 42, 2020, and week 24, 2021, and between week 37, 2021, and week 2, 2022. The results showed that Spike Screen can be applied to monitor VOC/VOI mutations among large volumes of samples in settings with limited sequencing capacity through reliable and rapid detection of novel variants at the population level and can serve as a basis for public health policy planning.

Application of on-line sample preconcentration by large-volume dual preconcentration by isotachophoresis and stacking (LDIS) on straight-channel microchips.

In this study, large-volume dual preconcentration by isotachophoresis and stacking (LDIS) which is an on-line sample preconcentration technique coupling large-volume sample stacking with an electroosmotic flow pump (LVSEP) with transient isotachophoresis (tITP) was applied to microchip electrophoresis (MCE) for improving both detection sensitivities and peak shapes. To realize LDIS in MCE, we investigated experimental procedures for injecting a short plug of a leading electrolyte (LE) solution into a straight microchannel without any sophisticated injector apparatus. We found that a short LE plug could be injected into a sample-filled straight-channel only by making the liquid level of the LE solution in an outlet reservoir higher than that in an inlet one. By applying a reversed-polarity voltage to the microchip, anionic analytes injected throughout the microchannel were first enriched by LVSEP, followed by tITP. Through the second preconcentration effect by tITP in LDIS, sensitivity enhancement factor (SEF) and asymmetry factor for a standard dye were improved from 878 and 0.62 to 1330 and 1.14, respectively, relative to those in conventional LVSEP. It should be noted that more viscous running buffer containing sieving polymers could be employed to the LDIS analysis, which was effective for improving the SEF and the separation efficiencies, especially for bio-polymeric compounds. Finally, LDIS was applied to the oligosaccharide and protein analyses in MCE, resulting in the SEFs of 1410 and ca. 50 for maltotriose and bovine milk casein, respectively.

Enhanced microplastic retrieval efficiency from cultivated soil samples through optimized pre-treatment in density-based extraction

Accurate assessment of microplastic contamination levels in soil is critical to understanding the potential risks they pose to ecosystem health and for developing effective mitigation strategies. However, efficient methods for extracting microplastics from soil samples are still lacking. In this study, we optimized the existing extraction methods through the pre-treatment of soil samples. The pre-treatment-based protocol included several phases. Firstly, the soil samples were treated with anhydrous ethanol to remove biofilm and dirt adhering to the surface of microplastics. Subsequently, the samples were subjected to washing with a metal sieve under pressurized liquid flow to remove small sand particles trapped within the microplastic pores. To further enhance the extraction efficiency, a short pre-digestion step with 30% hydrogen peroxide was introduced to remove organic matter adhered to the microplastics’ surface, with the aim of restoring the density of environmental microplastics to their polymer components. Following the pre-treatment steps, a rapid and efficient microplastic flotation process was conducted using a 1.5 g/cm3 ZnCl2 solution. Spiking experiments using microplastics demonstrated this method could process a large sample volume (100 g dry weight) and achieve high extraction efficiencies ranging from 88 % to 96 % for different microplastic types. The extracted microplastics were found to be virtually free of impurities, facilitating subsequent qualitative and quantitative analyses. Validation experiments further confirmed the superiority of the optimized method compared to traditional density-based approaches. The optimized method yielded 50.7% more microplastics than traditional density-based methods, it exhibited a significant advantage (p < 0.05) in the extraction of polyethylene, with an extraction rate increase of 88.6 %. The high efficiency of this method in extracting microplastics was thoroughly demonstrated. It represents a simple, low-cost, efficient, and low-toxicity approach for extracting microplastics from soil samples. Consequently, it holds significant potential for inclusion in future standardization efforts regarding microplastic extraction from soil samples.

Characterization and health risks of short- and medium-chain chlorinated paraffins in the gas and size-fractionated particulate phases in ambient air

Short-chain and medium-chain chlorinated paraffins (SCCPs and MCCPs) have garnered significant attention because they have persistence and potential toxicity, and can undergo long-distance transport. Chlorinated paraffins (CPs) inhaled in the size-fractionated particulate phase and gas phase can carry different risks to human health due to their ability to accumulate in different regions of the respiratory tract and exhibit varying deposition efficiencies. In our study, large-volume ambient air samples in both the size-fractionated particulate phase (Dp < 1.0 μm, 1.0–2.5 μm, 2.5–10 μm, and Dp ≥ 10 μm) and gas phase were collected simultaneously in Beijing using an active sampler. The overall levels of SCCPs and MCCPs were relatively high, the ranges being 57–881 and 30–385 ng/m3, respectively. SCCPs tended to be partitioned in the gas phase (on average 75% of the ΣSCCP concentration), while MCCPs tended to be partitioned in the particulate phase (on average 62% of the ΣMCCP concentration). Significant correlations were discovered between the logarithm-transformed gas–particle partition coefficients (KP) and predicted subcooled vapor pressures (PL0) (p < 0.01 for SCCPs and MCCPs) and between the logarithm-transformed KP values and octanol–air partition coefficients (KOA) (p < 0.01 for SCCPs and MCCPs). Thus, the slopes indicated that organic matter absorption was the dominant process involved in gas–particle partitioning. We used the ICRP model to calculate deposition concentrations for particulate-associated CPs in head airways region (15.6–71.4 ng/m³), tracheobronchial region (0.8–4.8 ng/m³), and alveolar region (5.1–21.9 ng/m³), then combined these concentrations with the CP concentrations in the gas phase to calculate estimated daily intakes (EDIs) for inhalation. The EDIs for SCCPs and MCCPs through inhalation of ambient air for the all-ages group were 67.5–184.2 ng/kg/day and 19.7–53.7 ng/kg/day, respectively. The results indicated that SCCPs and MCCPs in ambient air do not currently pose strong risks to human health in the study area.

Influence of suspended particles and dissolved organic matters on virus enrichment in reclaimed water by two-step tangential flow ultrafiltration: Phenomena and mechanisms

Enteric virus concentration in large-volume water samples is crucial for detection and essential for assessing water safety. Certain dissolution and suspension components can affect the enrichment process. In this study, tangential flow ultrafiltration (TFUF) was used as an enrichment method for recovering enteric virus in water samples. Interestingly, the bacteriophage MS2 recovery in reclaimed water and the reclaimed water without particles were higher than that in ultrapure water. The simulated reclaimed water experiments showed that humic acid (HA) (92.16% ± 4.32%) and tryptophan (Try) (81.50 ± 7.71%) enhanced MS2 recovery, while the presence of kaolin (Kaolin) inhibited MS2 recovery with an efficiency of 63.13% ± 11.17%. Furthermore, Atomic force microscopy (AFM) revealed that the MS2-HA cluster and the MS2-Try cluster had larger roughness values on the membrane surface, making it difficult to be eluted, whereas MS2-Kaolin cluster had compact surfaces making it difficult to be eluted. Additionally, the MS2-HA cluster is bound to the membrane by single hydrogen bond with SO, whereas both the MS2-Try cluster and the MS2-Kaolin cluster are bound to the membrane by two hydrogen bonds, making eluting MS2 challenging. These findings have potential implications for validating standardized methods for virus enrichment in water samples.