Ultrapure Water Research Articles

Polypyrrole as Adsorbent in Magnetic Solid Phase Extraction for Progesterone Determination from Human Plasma.

A straightforward and effective chromatographic method has been created for the analysis of progesterone from human plasma using a composite based on polypyrrole/magnetic nanoparticles in the sample preparation procedure. The quantification of progesterone is necessary due to its importance in human development and fertility. The employed conditions used acetonitrile:ultrapure water (70:30, v/v) as the mobile phase at 1.0 mL min-1 and an octadecyl silane column (Phenomenex Gemini, 250 mm × 4.6 mm, 5 μm) at a wavelength of 235 nm. The composite and its precursors were synthesized and properly characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy/energy dispersive spectroscopy, thermogravimetric analysis, and point of zero charge. The main factors affecting the extraction recovery of progesterone from pool human plasma samples employing magnetic solid phase extraction have been studied, such as sample pH (without adjustment), sample volume (1000 μL), washing solvent (ultrapure water), eluent (acetonitrile), eluent volume (1000 μL), and amount of adsorbent (10 mg). The extraction recoveries ranged from 98% to 102%, and linearity ranged from 5 to 3000 ng mL-1. The correlation coefficient (r) was ≥0.99, and acceptable relative standard deviation (precision), relative error (accuracy), and p-values (robustness) were observed. Lastly, the plasma samples from pregnant women were successfully analyzed by the validated method.

Chemometrics and analytical blank on the at-line monitoring of Zika-VLP production using near-infrared spectroscopy

The Zika disease caused by the Zika virus was declared a Public Health Emergency by the World Health Union (WHO), with microcephaly as the most critical consequence. Aiming to reduce the spread of the virus, biopharmaceutical organizations invest in vaccine research and production, based on multiple platforms. A crescent vaccine production approach is based on virus-like particles (VLP), for not having genetic material in its composition, hypoallergenic and non-mutant character. For bioprocess, it is essential to have means of real-time monitoring, which can be assessed using process analysis techniques such as Near-infrared (NIR) spectroscopy, that can be combined with chemometric methods, like Partial-Least Squares (PLS) and Artificial Neural Networks (ANN) for prediction of biochemical variables. This work proposes a biochemical Zika VLP upstream production at-line monitoring model using NIR spectroscopy comparing sampling conditions (with or without cells), analytical blank (air, ultrapure water), and spectra pre-processing approaches. Seven experiments in a benchtop bioreactor using recombinant baculovirus/Sf9 insect cell platform in serum-free medium were performed to obtain biochemical and spectral data for chemometrics modeling (PLS and ANN), composed by a random data split (80 % calibration, 20 % validation) for cross-validation of the PLS models and 70 % training, 15 % testing, 15 % validation for ANN. The best models generated in the present work presented an average absolute error of 1.59 × 105 cell/mL for density of viable cells, 2.37 % for cell viability, 0.25 g/L for glucose, 0.007 g/L for lactate, 0.138 g/L for glutamine, 0.18 g/L for glutamate, 0,003 g/L for ammonium, and 0.014 g/L for potassium.

High recovery design of reverse osmosis process with high permeate water quality and low wastewater discharge for ultra-pure water production

Ultra-pure water (UPW) for electronic industry is produced via many unit processes including reverse osmosis (RO), pretreatments, membrane degasifier, and ion exchange processes. Generally, 2-pass RO system is adopted in UPW production process to remove ionic and organic matters to meet water quality requirements of post-treatments. Since RO concentrate occupies most of wastewater discharged from UPW production process, high recovery design is beneficial to reduce wastewater discharge. According to the solution-diffusion model, permeate concentrations increase at higher feed concentrations, which may limit to increase RO recovery. Interestingly, the bench-scale 2-pass RO test using five commercial membrane modules revealed permeate concentrations were not affected by feed concentrations below a critical value (35 mg/L as NaCl in this work). This means the first-pass RO recovery can be increased without decreasing permeate water quality as far as second-pass RO feed concentrations are below the critical values. Various 2-pass UPW-RO system designs (250 mg/L as NaCl of feed concentration) were analyzed using an industrial RO system simulator to investigate the effect of the first- and second-pass recovery. The simulation works found that increasing the first- and second-pass recovery decreased wastewater discharge, energy consumption, and the number of membrane modules without degrading permeate water quality.

Novel umami-enhancing peptides of beef M. Semimembranosus hydrolysates and interactions with the T1R1/T1R3 taste receptor

The taste mechanisms of beef umami and umami-enhancing peptides are not well understood. Therefore, novel umami and umami-enhancing peptides from beef M. semimembranosus hydrolysates were explored. Beef hydrolysates treated with Flavourzyme® showed an overall strong umami intensity compared to those treated with Alcalase®, papain, or Protamex®. The peptides were isolated via consecutive separation processes, and 31 potential umami peptides were identified. Molecular docking results showed that WGSEPIRIQ and TERGYSF had considerably low docking energies with the T1R1/T1R3 taste receptor through potential key binding sites for hydrogen bonding, including Ser48, Gly49, and Gln278 in T1R1, and Ser67, Asn68, and Arg247 in the T1R3 subunit. The taste of the identified peptides dissolved in ultrapure water was dominated by sourness. Instead, they demonstrated an umami-enhancing effect in the presence of monosodium glutamate. These results broaden our understanding of the taste mechanisms of beef umami-enhancing peptides and their potential applications as flavoring agents.

Sustainable urea treatment by environmental-friendly and highly hydrophilic vesicle-like iron phosphate-based carbon

Despite the versatile potential applications of urea, its unfavorable characteristics for conventional treatment methods hinder its utilization. Therefore, this study developed vesicle-like iron phosphate-based carbon (IP@C400) as a breakthrough urea removal and recovery material for a wide range of urea-containing sources. IP@C400 rapidly exhibited an exceptional capacity (2242 mg/g in 1 h) across a wide range of pH, even in synthetic hemodialysis wastewater with high urea concentrations and diverse co-existing components, compared with the 60 prominent adsorbents. The adsorption process followed dual Pseudo-kinetic, Langmuir-isotherm models with the involvement of primary robust physical (i.e., H-bonding and electrostatic interaction) and chemical mechanisms (i.e., hydrolysis). Remarkably, IP@C400 can maintain high urea removal (90 %) or recovery efficiency (95 %) even after 10 cycles with minimal leakages of Fe and P (far below WHO and EUWFD standards)—a significant improvement over disposable options. IP@C400 could also perform efficiently on batch and a new approach integrating with a naturally accessible material based on the fixed-bed column using low-range urea realistic samples, achieving 65.2 L water over 10 cycles with undetected urea, neutral pH, and well-aligned water safety standards with a minimal adsorbent dose (0.1 g.L−1) and economical cost ($0.05 L-1). Lastly, its environmentally friendly nature, which contains essential nutrients for plant growth, further enhances its recyclability after release. Thus, IP@C400 offers a solution to environmental sustainability and the urgent ultrapure water issue that industries are facing.

Digital One-Step Competitive Detection of a Small Molecule in Synthetic and Environmental Waters.

Optical methods for single-molecule analysis hold the promise of accurate, sensitive, and rapid detection of target molecules. Here, we demonstrate the efficiency of such an approach for the competitive detection of small molecules in water. Our biosensing method is based on a combination of a single-DNA biochip for the parallelization of tethered particle motion real-time measurements with antibodies and modified targets as molecular competitors. The antibodies are coupled to the particles tethered to the surface by a long DNA bearing in its middle the molecular competitor bound to the antibodies. Competitive target binding leads to a detectable conformational change of the DNA tethers from looped to unlooped in proportions related to the target concentration. We thus managed to detect fluorescein, chosen as a model of a target molecule, in freshwater of various qualities, from solutions prepared with ultrapure water to more complex matrices such as river water and wastewater treatment plant effluent samples. Similar dose-response curves were obtained under these various conditions in a wide range of concentrations from nanomolar to micromolar with a limit of detection around 2 nM.

Assessing the Preservation Effectiveness: A Comparative Study of Plasma Activated Water with Various Preservatives on Capsicum annuum L. (Jalapeño and Pusa Jwala)

The study investigates the efficacy of plasma-activated water (PAW) in preserving green chillies (jalapeño and pusa jwala) and compared it with various household fruits and vegetables cleaners’ solutions. PAW was prepared using a pencil plasma jet with air as the plasma forming gas. The results of visual analysis revealed that PAW-treated chillies maintain their fresh appearance even after 21 days, exhibiting significantly lower spoilage compared to control (ultrapure milli-Q water) and fruits and vegetables cleaners’ solutions. PAW demonstrated antimicrobial properties, effectively reducing microbial growth and spoilage on chillies over the storage period. Physical attributes, such as weight loss and firmness, are evaluated. It has been observed that PAW-treated chillies exhibit lower weight loss and higher firmness, indicating better membrane integrity and moisture retention. Microbial resistance was notably higher in PAW-treated chillies compared to control and when cleaning solutions were used. CIELAB color analysis revealed that PAW-treated chillies retain greenness, and color, freshness, outperforming control and cleaners. Sensory evaluation, including visual inspection, smell, taste, and touch, consistently favored PAW-treated chillies, emphasizing their superiority in terms of enhancement in shelf-life. Biochemical analysis revealed that PAW-treated chillies either maintain or show enhancement in nutritional attributes such as soluble sugar, protein, and ascorbic acid concentrations. Phenol concentration (antioxidant activity) remained stable across treatments. Overall, the study underscores the positive impact of PAW treatment on preserving the membrane integrity, antimicrobial resistance, sensory quality, and nutritional attributes of green chillies, making PAW an alternative for extending their shelf life.

Heavy halogen compositions of peridotite massifs in the Ivrea-Verbano Zone and implications for strong modification of mantle rocks

The lithospheric mantle affected by metasomatism is an important reservoir for halogens and often preserves significant heterogeneity in halogen abundances. However, the halogen compositions of the non-metasomatized mantle rocks with depleted geochemical features have not been well studied, impeding a comprehensive understanding of the halogen distribution in the mantle. The Balmuccia (BM) and Baldissero (BD) peridotite massifs in the Ivrea-Verbano Zone, Italian Alps, represent fragments of the sub-continental lithospheric mantle (SCLM) that are fresh and devoid of subduction-related mantle metasomatism. Here we examine the heavy halogen contents of well-characterized spinel-facies mantle peridotites (n = 20) and pyroxenites (n = 16) from the BM and BD massifs. The results indicate significant variation in whole rock halogen contents of peridotites and pyroxenites, with chlorine (Cl) ranging from <30 to 244 μg/g, bromine (Br) from <0.10 to 0.94 μg/g, and iodine (I) from <0.015 to 0.12 μg/g. Some peridotites and pyroxenites show rather low halogen contents (below the detection limit), consistent with their depleted features. However, a large number of samples display halogen contents far higher than the depleted MORB mantle (i.e., Cl: 3–10 μg/g) and peridotite xenoliths from the strongly metasomatized mantle, although ∼30 % of the halogens were leached out by ultrapure water or dilute nitric acid. The data suggest variable halogen enrichment in many mantle rocks. The halogen contents of different types of mantle rocks do not vary with major elements and incompatible trace elements (e.g., Nb), indicating that halogen compositions are not controlled by magmatic processes such as melting and melt-peridotite reaction. Instead, secondary fluid inclusions are abundant and mainly distributed as trails within olivine and pyroxene in both peridotites and pyroxenites, which were likely trapped during the exhumation of these mantle rocks. Their elevated halogen/Nb ratios compared with MORB mantle and strong correlations with Ba/Nb support the effect of fluids. Micro-Raman analyses identify hydrous serpentines within fluid inclusions. Moreover, mass balance calculation indicates that halogen enrichment is mainly caused by secondary fluids (> 90 %). Together, our findings highlight that the fluid percolation in the mantle rocks during exhumation can intensely modify the halogens, to a similar degree as mantle metasomatism, suggesting the sensitivity of halogens to secondary modification.

Interplay between fluorine and cadmium on intestinal accumulation, oxidative stress, permeability and inflammatory response in rats

Fluorine (F) and Cadmium (Cd) have given rise to public concern regarding their adverse impacts on the environment and human beings. Yet, the toxic interplay between F and Cd on the intestine is still vague. Aiming to investigate the role of F on Cd-damaged intestine, a total of five groups of 30 SD rats were picked at random to be gavaged for 90 days: Control group (Ultra-pure water), Cd (Cd 1 mg/kg), Cd+LF (Cd 1 mg/kg+F 15 mg/kg), Cd+MF (Cd 1 mg/kg+F 45 mg/kg), and Cd+HF (Cd 1 mg/kg+F 75 mg/kg). It demonstrated that Cd enriched in the intestine and disordered intestinal barrier of rats. Interestingly, two side effects of F were observed resisting to the Cd toxicity. The Cd levels in colon contents were attenuated by 45.45 %, 28.11 %, and 19.54 % by F supplement, respectively. In the Cd+LF group, SOD, GSH-Px, and CAT activities elevated by 0.93, 1.76, and 1.78 times, respectively, and the MDA content reduced 0.67 times; the expressions of NQO1, SOD2, and GSH-Px mRNA markedly enhanced, as well as the Keap1 mRNA significantly decreased. Nevertheless, all indexes above in the Cd+HF group showed the opposite trends. Furthermore, LPS levels decreased by 45.93 % for the Cd+LF group and increased by 12.70 % in that the Cd+HF group. The ZO-1 expression in the Cd+LF group increased, whereas the Cd+HF group's expressions of Claudin-1, Occludin, and ZO-1 were all diminished by 35.46 %, 27.23 %, and 16.32 %, respectively. Moreover, the levels of TNF-α, IL-1β and TLR-4 decreased and IL-10 level promoted, while all showed opposite trends in the Cd+HF group. Collectively, it indicated there is a twofold interplay between F and Cd on intestinal damage and mainly depends on F dosages.

Nanobubbles in Ultrapure Water Can Self-Propel.

Nanobubbles are sub- micron-sized gas entities that find applications in a wide range of scientific fields. Typically, they are thought to diffuse according to Brownian motion. We report the existence of self-propelled motion of oxygen bulk nanobubbles in ultrapure water at body temperature. Their motion, to a large extent, is self-affine; there are different scaling exponents along the x- and y-axes as well as for the lateral displacement. We use fractal analysis, and we calculate the structure function, the normalised velocity autocorrelation function, the skewness, and the kurtosis. All descriptors attest the existence of a quasi-Gaussian stochastic process, which is classified as fractional Brownian motion. More than 50 \% of the trajectories along the x-axis follow superdiffusion, while this amount drops to 30 \% for motion along the y-axis as a result of the asymmetry of the field of view.

Rapid removal of multidrug-resistant bacteria and multidrug-resistant genes in drinking water and hospital wastewater using permanganate/bisulfite oxidation

Bacterial pathogens with multidrug resistance (MDR) characteristics pose a significant public health concern, impeding the effective utilization of antibiotics. In this study, a bisulfite/permanganate (PM/BS) process was used for the rapid inactivation of antibiotic-resistant bacteria (ARBs) and the elimination of antibiotic-resistance genes (ARGs). Targeting multidrug-resistant Escherichia coli (MDR E. coli), the PM/BS process rapidly reduced 3.09-log and 1.05-log within 10 s in real hospital effluent and tap water, respectively. Control experiments revealed enhancements in the inactivation of MDR E. coli with the presence of dissolved oxygen, Fe3+, Mg2+, and Cl−, whereas CO32− and HA inhibited water disinfection. Additionally, the PM/BS process significantly reduced the absolute abundance of two mobile genetic elements (MGEs) and a total of 52 ARGs across nine classes. These genes are responsible for MDR E. coli resistance to clinically important cephalosporins and carbapenems. The removal efficiencies of nine classes of ARGs varied from 91.49 to 98.17 % in ultrapure water and from 28.58 to 87.18 % in hospital effluent, respectively. The average removal efficiency of MGEs in hospital effluent also reached 71.94 %. In-situ generated Mn (III)aq and SO4∙- were further found as key contributors to the rapid inactivation of MDR E. coli and the reduction of ARGs and MGEs. This resulted in severe damage to cell membranes, significant K+ leakage, and protein degradation in MDR E. coli. These findings highlight the potential of the PM/BS process for rapid and efficient inactivation of ARBs and ARGs in both wastewater and drinking water, offering an alternative to traditional oxidants and opening avenues for the application of reactive Mn (III) species in disinfection.

Effect of potassium salt type on physicochemical properties of carrageenan films and rehydrated hydrogels

This study focused on the effect of potassium salt type on the physicochemical properties of carrageenan (Car) films and rehydrated hydrogels, with the aim of developing a new method for the preparation of Car hydrogels. The addition of potassium salt decreased the tensile strength (TS) of Car films, especially those containing KI. After rehydration, the weight and thickness change ratios of the Car films decreased with salt addition, and the sequence was as follows: K2CO3 < KH2PO4 < CH3COOK < KCl < K2SO4 < KSCN < KI < C6H5K3O7. The effect of potassium salt type on the TS and thermal transition temperature of rehydrated hydrogels was opposite that on weight and thickness change ratios. The hydrogels with K2CO3, KH2PO4, CH3COOK, KCl, and K2SO4 exhibited lower transverse relaxation time (T2) and smaller pore size compared with the other hydrogels. On the other hand, the effect of potassium salt type on hydrogels prepared using Car films soaked in potassium salt solution (S-Car) was similar to that observed on hydrogels prepared using Car films with potassium salt soaked in ultrapure water (U-Car). Compared with U-Car hydrogels, the S-Car hydrogels had higher TS and thermal transition temperature and lower elongation at break, T2, pore size, and hydrogen bond intensity. In conclusion, the potassium salt type and soaking method can be used to regulate the properties of Car hydrogels and provide a theoretical basis for the design of Car hydrogels.

Apelin-13-Loaded Macrophage Membrane-Encapsulated Nanoparticles for Targeted Ischemic Stroke Therapy via Inhibiting NLRP3 Inflammasome-Mediated Pyroptosis.

Ischemic stroke is a refractory disease wherein the reperfusion injury caused by sudden restoration of blood supply is the main cause of increased mortality and disability. However, current therapeutic strategies for the inflammatory response induced by cerebral ischemia-reperfusion (I/R) injury are unsatisfactory. This study aimed to develop a functional nanoparticle (MM/ANPs) comprising apelin-13 (APNs) encapsulated in macrophage membranes (MM) modified with distearoyl phosphatidylethanolamine-polyethylene glycol-RVG29 (DSPE-PEG-RVG29) to achieve targeted therapy against ischemic stroke. MM were extracted from RAW264.7. PLGA was dissolved in dichloromethane, while Apelin-13 was dissolved in water, and CY5.5 was dissolved in dichloromethane. The precipitate was washed twice with ultrapure water and then resuspended in 10 mL to obtain an aqueous solution of PLGA nanoparticles. Subsequently, the cell membrane was evenly dispersed homogeneously and mixed with PLGA-COOH at a mass ratio of 1:1 for the hybrid ultrasound. DSPE-PEG-RVG29 was added and incubated for 1 h to obtain MM/ANPs. In this study, we developed a functional nanoparticle delivery system (MM/ANPs) that utilizes macrophage membranes coated with DSPE-PEG-RVG29 peptide to efficiently deliver Apelin-13 to inflammatory areas using ischemic stroke therapy.MM/ANPs effectively cross the blood-brain barrier and selectively accumulate in ischemic and inflamed areas. In a mouse I/R injury model, these nanoparticles significantly improved neurological scores and reduced infarct volume.Apelin-13 is gradually released from the MM/ANPs, inhibiting NLRP3 inflammasome assembly by enhancing sirtuin 3 (SIRT3) activity, which suppresses the inflammatory response and pyroptosis. The positive regulation of SIRT3 further inhibits the NLRP3-mediated inflammation, showing the clinical potential of these nanoparticles for ischemic stroke treatment. The biocompatibility and safety of MM/ANPs were confirmed through in vitro cytotoxicity tests, blood-brain barrier permeability tests, biosafety evaluations, and blood compatibility studies. MM/ANPs offer a highly promising approach to achieve ischemic stroke-targeted therapy inhibiting NLRP3 inflammasome-mediated pyroptosis.

Characterization of Langmuir Monolayers for Nanodiamonds Surface‐Modified with 12‐Hydroxystearyl Chains and the Occurrence of Structural Colors

AbstractThe surfaces of nanodiamond particles are modified using natural castor oil‐derived 12‐hydroxystearic acid, which has thixotropic solvent properties. 12‐Hydroxystearyl chain‐modified nanodiamonds (12OHSt‐ND) are spread from a dispersion medium onto ultrapure water to afford Langmuir monolayers (a single‐particle layer) of 12OHSt‐ND exhibited a two‐dimensional phase transition from an expanded phase to a condensed phase. The surface morphology of the single‐particle layer shows a dispersed form of aggregated particles, while the layered regularity of the multilayers shows high periodicity. The surface hydrophobicity of the single‐particle layer of 12OHSt‐ND is more pronounced than that of the single‐particle layer of stearic acid‐modified nanodiamonds. The origin of the surface hydrophobicity of the single‐particle layer of 12OHSt‐ND is predicted to be the vertical conformation of the modified chains achieved via hydrogen bonding between the modified chains. In addition, the stepwise multilayers of 12OHSt‐ND exhibit various structural colors depending on the number of layers.

Determination of eight neonicotinoid pesticides in wastewater by solid phase extraction combined with liquid chromatography-tandem mass spectrometry

Neonicotinoid pesticides are a relatively new class of pesticides that have garnered significant attention owing to their potential ecological risks to nontarget organisms. A method combining solid phase extraction with liquid chromatography-tandem mass spectrometry (SPE-LC-MS/MS) was developed for the rapid and accurate detection of eight neonicotinoid pesticides (dinotefuran, E-nitenpyram, thiamethoxam, clothianidin, imidacloprid, imidaclothiz, acetamiprid, and thiacloprid) in wastewater. The chromatographic mobile phase and MS parameters were selected, and a single-factor method was used to determine the optimal column type, extraction volume, sample loading speed, and pH for SPE. The optimal parameters were as follows: column type, HLB column (500 mg/6 mL); sample extraction volume, 500 mL; sample loading speed, 10 mL/min; and sample pH, 6-8. The matrix effects of the wastewater samples were reduced by optimizing the chromatographic gradient-elution program, examining the dilution factor of the samples, and using the isotope internal standard calibration method. Prior to analysis, the wastewater samples were diluted 5-fold with ultrapure water for pretreatment. Subsequently, 2 mmol/L ammonium acetate aqueous solution containing 0.1% (v/v) formic acid and methanol was used as mobile phases for gradient elution on a ZORBAX Eclipse Plus C18 column (100 mm×2.1 mm, 1.8 μm). The samples were quantified using positive-ion multiple reaction monitoring (MRM) mode for 10 min. Imidacloprid-d4 was used as the isotope internal standard. The SPE process was further optimized by applying response surface methodology to select the type and mass of rinsing and elution solvents. The optimal pretreatment of the SPE column included rinsing with 10% methanol aqueous solution and elution with methanol-acetonitrile (1∶1, v/v) mixture (7 mL). The eight neonicotinoid pesticides showed satisfactory linearity within the relevant range, with linear correlation coefficients (r) all greater than 0.9990. The method detection limits (MDLs) ranged from 0.2 to 1.2 ng/L, and the method quantification limits (MQLs) ranged from 0.8 to 4.8 ng/L. The average recoveries of the eight neonicotinoid pesticides were in the range of 82.6%-94.2% at three spiked levels, with relative standard deviations (RSDs) ranging from 3.9% to 9.4%. Finally, the optimized method was successfully applied to analyze wastewater samples collected from four sewage treatment plants. The results indicated that the eight neonicotinoid pesticides could be generally detected at concentrations ranging from not detected (ND) to 256 ng/L. The developed method has a low MDL and high accuracy, rendering it a suitable choice for the trace detection of the eight neonicotinoid pesticides in wastewater when compared with other similar methods. The proposed method can be utilized to monitor the environmental impact and assess the potential risks of neonicotinoid pesticides in wastewater, thus promoting the protection of nontarget organisms and the sustainable use of these pesticides in agriculture.

Total organic carbon quantification in soils and sediments: Performance test of a modified sample preparation method

The total organic carbon (TOC) concentration of particulate samples is a key parameter to characterize soils and sediments. To demonstrate the applicability and reliability of a modified sample preparation method for the direct measurement of TOC contents in suspended particulate samples, we analyzed five certified reference materials (CRMs) with varying TOC concentrations using a Shimadzu TOC-L CPH analyzer. Measured values were calibrated with a multi-point curve that cover the full range of the expected TOC concentrations and the results were validated using statistical values and measures. The method validation reveals that the measurements are accurate and precise for CRMs from marine and soil contexts, but show a low accuracy for the CRM containing polycyclic aromatic hydrocarbons (PAHs). This demonstrates the applicability and reliability of the modified preparation method for direct TOC determination of suspended particulate samples. Therefore, it is relevant for a broader community, beyond geosciences, and for users employing devices of other manufacturers to analyze TOC in suspended particulate samples.•Modified preparation method uses reduced sample weights and yields accurate and precise results.•Cost-efficient and environmentally friendly alternative: reduces waste by saving acid and ultrapure water.•Avoids incomplete dissolution of dolomite by heating acidified samples.

Silver Core Coated with Molecularly Imprinted Polymer as Adsorbent in Pipet-Tip Solid Phase Extraction for Neonicotinoids Determination from Coconut Water.

In this work, we report an innovative adsorbent named Ag-MPS@MIP that has a core@shell structure, i.e., silver nanoparticles modified with 3-methacryloxypropyltrimethoxysilane as the core and molecularly imprinted polymer based on methacrylic acid as its shell. Thiamethoxam, imidacloprid, and acetamiprid were extracted from coconut water samples using Ag-MPS@MIP in pipet-tip solid phase, prior to high-performance liquid chromatography analysis. The separation was carried out on isocratic mode using a mobile phase consisting of C18 column (Phenomenex, 150 mm × 4.6 mm, 5 μm), ultrapure water acidified with 0.3% phosphoric acid:acetonitrile (78:22, v/v), flow rate at 1.0 mL min-1, injection volume of 10 μL, temperature of 25 °C, and wavelength at 260 nm. The adsorbent and precursor materials were properly characterized by different instrumental techniques. The main factors affecting the recovery of analytes from coconut water samples by pipet-tip solid phase were optimized, such as sample volume (250 μL), sample pH (pH = 5.0), ionic strength (1%, m/v), washing solvent (300 μL ultrapure water), volume and type of eluent (500 μL methanol), amount of adsorbent (15 mg), cycle of percolation-dispensing (1×), and reuse (5×). Thereby, the neonicotinoids presented extraction recoveries between 82.80 and 96.36%, enrichment factor of 5, linearity ranged from 15 to 4000 ng mL-1, correlation coefficient (r) > 0.99, limit of detection of 5 ng mL-1, satisfactory selectivity, stability, and proper precision (RSD%: 0.52-9.64%) and accuracy (RE%: -5.19-6.45%). The method was successfully applied to real samples of coconut water.

Preparation, Characterization, and Testing of Compost Tea Derived from Seaweed and Fish Residues

Non-aerated compost tea (CT) was prepared from compost derived from rockweed (Ascophyllum nodosum) and fish (cod, common ling, haddock, saithe) residues that fermented in water. Electrical conductivity, pH, concentrations of dry matter, ash, C, macronutrients (N, P, K, Ca, and Mg), and micronutrients (Cu, Fe, Mn, Mo, and Zn) of CT prepared under different fermentation conditions were measured. The effects of process factors, i.e., water/compost mass ratio (4.2–9.8 g/g) and fermentation time (4.2–9.8 days = 100–236 h), on the physicochemical properties of CT were quantified using quadratic polynomial models. CT obtained at optimal levels of process factors (4.2 g/g and 5.6 days = 134 h) was tested for lettuce seed germination and seedling growth. Diluted CT (25% CT + 75% ultrapure water) improved seedling growth while achieving a high germination percentage (97%).

Optimizing the Synthesis of Titanium Carbide-Bismuth Oxide for Enhanced Antimicrobial Properties.

Background The two-dimensional MXene, known as titanium carbide (Ti₃C₂), is characterized by its substantial interlayer spacing, extensive surface area, hydrophilic nature, exceptional thermal stability, and outstanding electrical conductivity. These distinctive attributes render Ti₃C₂ an ideal candidate for detecting target analytes and immobilizing biomolecules. Bismuth oxide (Bi₂O₃), an essential compound of bismuth, frequently acts as a foundational element in bismuth chemistry. Its applications are diverse, from fireworks to oxygen gas sensors and solid oxide fuel cells, with particular emphasis on its behaviour under elevated temperatures and pressures. Notably, phase transitions to various polymorphs, which remain metastable at room temperature, have been documented under these conditions, indicating potential for numerous applications. Integrating MXene with Bi₂O₃ composites holds significant promise for advancements in energy-related electronics, sensing technologies, and photocatalytic processes. Objective To optimize the synthesis of titanium carbide-bismuth oxide (Ti₃C₂-Bi₂O₃) nanoparticles to enhance their antimicrobial activity by identifying the best synthesis conditions and assessing their effectiveness against various microbial pathogens. Materials and methods The preparation of Ti₃C₂ MXene involves dissolving lithium fluoride in hydrochloric acid, followed by Ti₃AlC₂ and stirring at 40°C for 48 hours. The resulting pellet is then dispersed in ultrapure water and centrifuged to obtain the MXene dispersion. Bi₂O₃ nanoparticles are prepared by preparing bismuth nitrate pentahydrate in nitric acid and adding sodium hydroxide to adjust the pH. The resulting white precipitate is filtered, washed, and dried before being calcined at 400°C for two hours to produce Bi₂O₃ nanoparticles. The Ti₃C₂-Bi₂O₃ composite is synthesized by adding Bi(NO₃)₃ solution to a 5 mg/mL Ti₃C₂Tx MXene solution. The reaction solution is heated to 160°C, and the resulting black powder is labelled as x% Bi₂O₃/MXene. The antimicrobial efficacy of the nanoparticles is assessed using the disk diffusion method. The zones of inhibition are measured and analyzed as indicators of antimicrobial activity. Results The scanning electron microscopy (SEM) analysis revealed the presence of Bi₂O₃ particles alongside Ti₃C₂​​​​​​​ nanosheets, while the X-ray diffraction (XRD) analysis and energy-dispersive X-ray spectroscopy (EDS) confirmed the high crystallinity of the compound. Furthermore, the compound was determined to be impurity-free and demonstrated antimicrobial properties. Conclusion The XRDanalysis confirms the effective integration of various materials and the existence of crystalline phases. SEMprovides insights into the morphology and organization of particles within sheets, whereas EDSassesses the elemental composition and its uniform distribution. These studies demonstrate the synthesis of Ti₃C₂-Bi₂O₃​​​​​​​ composites, suggesting their potential for usage in applications involving antimicrobial action.

Boosting green hydrogen production with ZnS@MoS2 2D materials: A structural, electrochemical and photocatalytic analysis

Sustainable green hydrogen production and utilization is one of the serious options to net-zero emission and to mitigate climate change. Herein, a range of techniques has been employed to extricate structural alterations and assess electrochemical (EC) and photocatalytic (PC) properties of MoS2 and ZnS deposited MoS2 (ZnS@MoS2) 2D Materials for green hydrogen production. These 2D materials were explored via a simple hydrothermal method. X-Ray Diffraction (XRD) analysis of ZnS@MoS2 2D materials disclosed significant structural transformations, attributed to ZnS deposition, evident through peak shifts and the emergence of new peaks. Scanning electron microscopy (SEM) images revealed distinct flower-like, petal-arranged formations in MoS2 and ZnS@MoS2, while as high-resolution transmission electron microscopy (HR-TEM) images provided insights into the nanoscale structure and the d‐spacing of MoS2 and ZnS@MoS2 materials. X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were utilized to determine elemental composition, chemical states, and structural characteristics. Electrochemical assessments showed that MoS2 exhibited a hydrogen evolution reaction (HER) with an onset potential of −0.3 V, whereas ZnS@MoS2 demonstrated an improved HER with an onset potential of −0.25 V (relative to Ag/AgCl). Notably, the ultra-low overpotential (η@10) of −0.40 V for MoS2 and −0.30 V for ZnS@MoS2, underlined their exceptional catalytic effectiveness. Moreover, ZnS@MoS2 material accomplished an improved photocatalytic hydrogen evolution rate of 4663.5 µmolh−1g−1, surpassing MoS2’s rate of 3318.85 µmolh−1g−1. In conclusion, it is believed that ZnS@MoS2 material can be a potential candidate for green hydrogen production, not only by splitting ultrapure water but future work will explore the catalyst’s performance in seawater electrolysis.