Concentrations Of Target Compounds Research Articles

Comparative Analysis of Pharmaceutical Persistence in Canadian Wastewater Treatment Plants Utilizing Molecularly Imprinted Polymers and Commercial Solid Phase Extraction Sorbents

In this study, the performances of a synthesized Molecularly Imprinted Polymer (MIP) and a commercial Solid Phase Extraction (SPE) cartridge were compared in terms of the removal efficiency and quantification of pharmaceutical compounds in wastewater samples. Concentration analysis of Emtricitabine, Tenofovir, Naproxen, Diclofenac, Ibuprofen, and Efavirenz was conducted in influent, primary effluent, secondary effluent, and post-chlorination water samples using liquid chromatography-UV detection. Regressions analysis revealed high linearity (R2 values from 0.9980 to 0.9999) for the compounds, alongside recoveries ranging from 90.9% to 100%. The method detection limits (MDLs) were also determined. Removal efficiencies were computed, with Naproxen and Ibuprofen demonstrating complete removal (100%), while other compounds displayed different of removal efficiency levels. The MIP was found to perform slightly better than traditional SPE cartridges in terms of selectivity, efficiency, and overall performance. This study provides valuable insights into the concentrations of target compounds at various treatment stages, emphasizing the importance of choosing extraction cartridges in wastewater treatment processes.

Impact of Polyvinylpyrrolidone-Vinyl Acetate Copolymer and Sodium Starch Glycolate Excipients on Phenolic Extraction from Red Clover: Enhancing Biological Activity and Antioxidant Potential.

Adding certain excipients during the extraction process can enhance the concentration of target compounds, leading to potentially increased biological properties of the plant extract. This study explores the impact of PVP/VAC and SSG excipients on red clover bud extracts, aiming to enhance their concentration of target compounds and, consequently, their biological properties. The antioxidative potential was evaluated using DPPH, ABTS, and FRAP methods, and the chemical profile was determined using mass spectrometry. Antibacterial activity against various strains was determined through the minimal inhibitory concentration (MIC) method. The results revealed that the excipient-enriched samples exhibited significantly elevated antioxidant activities as well as phenolic and flavonoid contents compared to control samples. Notably, sample V1E3 demonstrated the highest antioxidant potential, with 52.48 ± 0.24 mg GAE/g dw (phenolic content), 463 ± 6.46 μg TE/g dw (ABTS), 12.81 ± 0.05 μg TE/g dw (DPPH), and 29.04 ± 1.16 mg TE/g dw (post-column ABTS). The highest flavonoid content was found in the S1E3 sample-24.25 ± 0.17 mg RU/g dw. Despite the increased antioxidant potential, no significant variance in antimicrobial activity was noted between the test samples and controls. This implies that excipients may hold the potential to enhance the biological properties of red clover extracts for pharmaceutical applications. These findings contribute valuable insights into optimizing extraction processes for improved functionality and application of plant-derived compounds in therapeutic formulations.

In-sample stability and postsampling analysis of 21 illicit drugs, their metabolites and cotinine in wastewater

A thorough understanding of the degradation of chemical biomarkers in wastewater after the sampling is critical in the surveillance of illicit drug use based on the back-calculation technique. Herein, three temperatures, eight groups of matrices, and acidification were applied to simulate the preservation condition of 21 illicit drugs, their metabolites, and cotinine for a 240-day stability study. It was proved that the temperature, matrices, and acidification play vital roles in their stability in wastewater. Most of them demonstrated high stability (transformation rates < 20%) during room temperature for 45 days, and the transformation rates decreased while the storage temperature reduced. The stability of the target compounds such as cocaine (COC), 6-monoacetylmorphine (6-MAM), and amphetamine (AM) is influenced by matrices. Acidification prevented the majority of analytes from transforming, making it a feasible solution for preservation after sampling. A model that combined the effects of temperature and matrix was developed to back-calculate the concentration of target compounds during the postsampling process. The feasibility of this model was validated by correcting the loss of COC and 6-MAM from 24.2% and 16.2% to 2.98% and 2.77%. This study simulated a typical large-scale sampling and storage scenario. The effect of the temperature, pH, and matrix on in-sample stability and the postsampling analysis of selected target compounds was investigated for the first time in this study.

Parabens, Triclosan and Bisphenol A in Surface Waters and Sediments of Baiyang Lake, China: Occurrence, Distribution, and Potential Risk Assessment.

The extensive use of the parabens triclosan (TCS) and bisphenol A (BPA) has potential adverse effects on human health and aquatic organisms. However, their monitoring information in freshwater lakes is still limited. This study simultaneously summarized the concentrations, spatial distribution characteristics, and correlations of four types of parabens, TCS, and BPA in the surface water and sediment of Baiyang Lake. Finally, the potential risks of target pollutants were evaluated from two aspects: human health risks and ecological risks. The average contaminations of target compounds in surface water and sediment-BPA, TCS, and ∑4 parabens-was 33.1, 26.1, 0.7 ng/L and 24.5, 32.5, 2.5 ng/g, respectively. The total concentration of target compounds at the inlet of the upstream Fu River and Baigouyin River is significantly higher than that near Hunan and the outlet. In addition, Spearman's correlation analysis showed a significant positive correlation between compounds. The health hazards of target compounds in surface water were all within safe limits. However, the risk quotient results indicate that in some locations in surface water, TCS poses a high risk to algae and a moderate risk to invertebrates and fish, and appropriate attention should be paid to these areas.

Study on simultaneous determination of OCPs, PCBs and PBDEs in fish sample: application for marine fish tissues collected from Hai Phong province

In this work, a GC-MS/MS-based analytical method using accelerated solvent extraction combined with multi-layer silica gel column for sample preparation was developed to simultaneously determine 20 organochlorine pesticides (OCPs), 28 polychlorinated biphenyls (PCBs) and 8 polybrominated diphenyl ethers (PBDEs) in fish tissue. The method detection limits (MDLs) were achieved in the range of 0.053 ng/g (&amp;alpha;-chlordane) &amp;ndash; 1.65 ng/g (&amp;delta;-BHC), 0.07 ng/g (PCB-209) &amp;ndash; 1.84 ng/g (PCB-28), 0.323 ng/g (BDE-209) &amp;ndash; 0.796 ng/g (BDE-47) for OCPs, PCBs and PBDEs, respectively. Intra-day and inter-day repeatability of the analytical signal (peak area) were below 10.5% and 12.4%, correspondingly. The overall recovery was investigated by spiking experiments and ranged from 70.9 to 114%. The confirmation of this developed method was assessed by analysis of the standard reference material (SRM-1947) sample. The measured concentrations of target compounds were within the range of the certified values. This developed method was applied for analysis of OCPs, PCBs and PBDEs in five fish tissues collected randomly from local markets at Hai Phong province. Their concentrations (&amp;lt;MDL &amp;ndash; 206 ng/g for OCPs, &amp;lt;MDL &amp;ndash; 20.7 ng/g for PCBs and &amp;lt;MDL &amp;ndash; 66.7 ng/g for PBDEs) were lower than the maximum residue levels permitted by European Union, Food and Agriculture Organization and World Health Organization.

Increasing the Robustness of SIFT-MS Volatilome Fingerprinting by Introducing Notional Analyte Concentrations.

Selected ion flow tube-mass spectrometry (SIFT-MS) is an analytical technique for volatile detection and quantification. SIFT-MS can be applied in a "white box" approach, measuring concentrations of target compounds, or as a "black box" fingerprinting technique, scanning all product ions during a full scan. Combining SIFT-MS full scan data acquired from multibatches or large-scale experiments remains problematic due to signal fluctuation over time. The standard approach of normalizing full scan data to the total signal intensity was insufficient. This study proposes a new approach to correct SIFT-MS fingerprinting data. In this concept, all of the product ions from a full scan are considered individual compounds for which notional concentrations can be calculated. Converting ion count rates into notional analyte concentrations accounts for any changes in the instrument parameters. The benefits of the proposed approach are demonstrated on three years of data from both multibatches and long-term experiments showing a significant reduction of system-induced fluctuations providing a better focus on the changes of interest.

Degradation of endocrine‐disrupting chemicals using various sulfate radical activation methods: kinetics and mechanism

AbstractBACKGROUNDMost studies have focused on the degradation of endocrine‐disrupting chemicals using persulfate activation processes. Therefore, the current study compares various sulfate radical activation processes in an aqueous solution of a mixture of diethyl phthalate, butylparaben and bisphenol A that are present in water and wastewater. The effects of initial persulfate dose and pH variation, the effect of concentration of target endocrine‐disrupting chemicals and degradation efficiency under various processes were studied. Additionally, the toxicity and cost estimation of the systems were also examined.RESULTSThe results showed pseudo‐first‐order kinetics with maximum degradation efficiency of 99% for 1 mg L−1 at pH 7, 2.5 mmol L−1 persulfate dose, 450 W power in 60 min for UV‐activated persulfate oxidation process. A quenching experiment highlights the dominance of both sulfate and hydroxyl radicals in the degradation of mixtures of diethyl phthalate, butylparaben and bisphenol A in an aqueous solution. The transformative products identified using gas chromatography–mass spectrometry were monohydroxylated structures that decompose to form organic acids, indicating efficient degradation capacity with minimal toxicity. Further, the sono‐activated persulfate oxidation process was found to be cost‐effective at 1 mg L−1 with 95% degradation efficiency.CONCLUSIONIt is concluded that an increase in the concentration of target compounds decreases the efficiency of degradation under various activation processes. pH 3 and pH 7 favor thermal and sono‐activated and UV‐activated processes, respectively. Toxicity evaluation shows minimal harm to non‐target species Daphnia magna for all activation processes. These findings can be useful for on‐field application for the degradation of chemicals in mixtures. © 2023 Society of Chemical Industry.

Alcohol perturbed locomotor behavior, metabolism, and pharmacokinetics of gamma-hydroxybutyric acid in rats

Gamma-hydroxybutyric acid (GHB), both a metabolic precursor and product of gamma-aminobutyric acid (GABA), is a central nervous system depressant used for the treatment of narcolepsy-associated cataplexy and alcohol withdrawal. However, administration of GHB with alcohol (ethanol) is a major cause of hospitalizations related to GHB intoxication. In this study, we investigated locomotor behavior as well as metabolic and pharmacokinetic interactions following co-administration of GHB and ethanol in rats. The locomotor behavior of rats was evaluated following the intraperitoneal administration of GHB (sodium salt, 500 mg/kg) and/or ethanol (2 g/kg). Further, time-course urinary metabolic profiling of GHB and its biomarker metabolites glutamic acid, GABA, succinic acid, 2,4-dihydroxybutyric acid (OH-BA), 3,4-OH-BA, and glycolic acid as well as pharmacokinetic analysis were performed. GHB/ethanol co-administration significantly reduced locomotor activity, compared to the individual administration of GHB or ethanol. The urinary and plasma concentrations of GHB and other target compounds, except for 2,4-OH-BA, were significantly higher in the GHB/ethanol co-administration group than the group administered only GHB. The pharmacokinetic analysis results showed that the co-administration of GHB and ethanol significantly increased the half-life of GHB while the total clearance decreased. Moreover, a comparison of the metabolite-to-parent drug area under the curve ratios demonstrated that the metabolic pathways of GHB, such α- and β-oxidation, were inhibited by ethanol. Consequently, the co-administration of GHB and ethanol aggravated the metabolism and elimination of GHB and enhanced its sedative effect. These findings will contribute to clinical interpretation of GHB intoxication.

Occurrence of hexabromocyclododecanes (HBCDs) and tetrabromobisphenol A (TBBPA) in indoor dust from different microenvironments: levels, profiles, and human exposure.

The levels and distributions of hexabromocyclododecane diastereoisomers (HBCDs) (including α, β, and γ-HBCD) and tetrabromobisphenol A (TBBPA) were investigated in indoor dust from bedrooms and offices. HBCDs diastereoisomers were the most abundant compounds in the dust samples, and the concentrations of ∑HBCDs in the bedrooms and offices ranged from 10.6 to 290.1ng/g and 17.6 to 1521.9ng/g, respectively. The concentrations of target compounds in the offices were generally higher than those in the bedrooms, probably due to the presence of more electrical equipment in the offices. In this study, highest levels of target compounds were all found in the electronics. In the bedrooms, the highest mean level of ∑HBCDs was found in air conditioning filter dust (118.57ng/g), while the personal computer table surface dust showed the peak mean concentrations of ∑HBCDs (290.74ng/g) and TBBPA (539.69ng/g) in the offices. Interestingly, a significantly positive correlation was observed between the concentrations of ∑HBCDs in windowsills and beddings dust in the bedrooms, suggesting beddings was one of the crucial sources of ∑HBCDs in the bedrooms. The high dust ingestion values of ∑HBCDs and TBBPA were 0.046 and 0.086ng/kgbw/day for adults, while 0.811 and 0.04ng/kgbw/day for toddlers, respectively. The high dermal exposure values of ∑HBCDs were 0.026 and 0.226ng/kgbw/day for adults and toddlers, respectively. Except for dust ingestion, other human exposure pathways (such as the dermal contact with beddings and furniture) should be paid attention.

Determination of carrageenan and konjac gum in livestock meat and meat products by ultra performance liquid chromatography–tandem mass spectrometry

ABSTRACT At present, gum-injected meat appeared in the market, which has seriously damaged the legitimate rights and interests of consumers. Therefore, a method for the determination of carrageenan and konjac gum in livestock meat and meat products by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established. The samples were hydrolyzed by hydrogen nitrate. After centrifugation and dilution, the supernatants were detected by the UPLC-MS/MS and the concentration of target compounds in samples were calibrated by the matrix calibration curves. A good linear relationship was observed in the concentration range of 5–100 μg/mL with correlation coefficients of more than 0.995. The limits of detection (LODs) and limits of quantification (LOQs) were found to be 20 and 50 mg/kg, respectively. The recoveries at three spiked levels (50, 100 and 500 mg/kg) in blank matrix were in the range of 84.8–108.6% with the relative standard deviations between 1.5% and 6.4%. The method has the advantages of convenient, accurate and efficient, and can be used as an effective method for detecting carrageenan and konjac gum in the different kinds of livestock meat and meat products.

Efficient electrochemical oxidation of cephalosporin antibiotics by a highly active cerium doped PbO2 anode: Parameters optimization, kinetics and degradation pathways

Removing cephalosporin contaminants from aquatic environments is of great concern because of the hazards they pose to the environment and human health. In this study, a Ce-PbO2 anode with a SnO2-Sb intermediate layer was fabricated using an electrochemical deposition method and used for the electrocatalytic oxidation of cephalosporin antibiotics. Scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirmed the successful preparation of the Ce-PbO2 anode and revealed that Ce doping resulted in a highly stable structure and crystallinity of the PbO2 crystals. Moreover, the Ce-PbO2 anode exhibited excellent electrochemical performance with higher oxygen evolution potential (1.56 V), larger electroactive surface area (1.104 C cm−2), smaller corrosion current density (1.796 × 10−4 A cm−2), and higher hydroxyl radical (•OH) yield (8.64 mM min−1 m−2) compared with the intermediate layer and PbO2 anode. The effects of major operating parameters, including current density (20–80 mA cm−2), electrolyte concentration (0.050–0.125 M), initial concentration of target compounds (5–75 mg L−1), and pH (2−10) on the removal efficiencies of cefradine (RAD), and cephalothin (CEP) at the Ce-PbO2 electrode were investigated. The research results illustrated that when electrolysis was carried out for 90 min at the optimal current density of 40 mA cm−2, an initial concentration of 50 mg L−1, and an electrolyte concentration of 0.10 M, the removal efficiency of RAD and CEP were higher than 99%. Additionally, the degradation process followed pseudo-first-order kinetics. The total organic carbon (TOC) removal efficiency of RAD and CEP was 60.6% and 68.2% after 240 min, respectively, under the optimal conditions. The energy consumption for RAD and CEP degradation was 1.74 and 3.04 kWh g−1 TOC, respectively. In addition, the Ce-PbO2 electrode exhibited good stability over nine consecutive cycles. Using UPLC-MS, the intermediate products of RAD and CEP were confirmed, and the degradation intermediates were completely oxidized to CO2, H2O, and inorganic ions (SO42-, NO3-). During electrolysis, the intermediate toxicity was studied using Escherichia coli growth inhibition tests, and the growth inhibition rate was calculated. Considering these results, the Ce-PbO2 anode could be utilized to treat wastewater containing cephalosporin antibiotics with high efficiency.

Matrix Effects in GC–MS Profiling of Common Metabolites after Trimethylsilyl Derivatization

Metabolite profiling using gas chromatography coupled to mass spectrometry (GC-MS) is one of the most frequently applied and standardized methods in research projects using metabolomics to analyze complex samples. However, more than 20 years after the introduction of non-targeted approaches using GC-MS, there are still unsolved challenges to accurate quantification in such investigations. One particularly difficult aspect in this respect is the occurrence of sample-dependent matrix effects. In this project, we used model compound mixtures of different compositions to simplify the study of the complex interactions between common constituents of biological samples in more detail and subjected those to a frequently applied derivatization protocol for GC-MS analysis, namely trimethylsilylation. We found matrix effects as signal suppression and enhancement of carbohydrates and organic acids not to exceed a factor of ~2, while amino acids can be more affected. Our results suggest that the main reason for our observations may be an incomplete transfer of carbohydrate and organic acid derivatives during the injection process and compound interaction at the start of the separation process. The observed effects were reduced at higher target compound concentrations and by using a more suitable injection-liner geometry.

PCBs, PCNs, and PCDD/Fs in Soil around an Industrial Park in Northwest China: Levels, Source Apportionment, and Human Health Risk.

The concentrations of polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were determined in soil samples collected around an industrial park in Northwest China, to investigate the potential impacts of park emissions on the surrounding environment. The total concentration ranges of PCBs, PCNs, and PCDD/Fs in the soil samples were in 13.2-1240, 141-832, and 3.60-156 pg/g, respectively. The spatial distribution and congener patterns of PCBs, PCNs, and PCCD/Fs indicated that there might be multiple contamination sources in the study area, so source apportionments of PCBs, PCNs, and PCCD/Fs were performed by a positive matrix factorization model based on the concentrations of all target congeners together. The results revealed that these highly chlorinated congeners (CB-209, CN-75, and OCDF) might be derived from phthalocyanine pigments, the legacy of Halowax 1051 and 2,4-D products, which together contributed nearly half of the total concentration of target compounds (44.5%). In addition to highly chlorinated congeners, the local industrial thermal processes were mainly responsible for the contamination of PCBs, PCNs, and PCDD/Fs in the surrounding soil. The total carcinogenic risk of PCBs, PCNs, and PCDD/Fs in a few soil samples (0.22 × 10-6, 0.32 × 10-6, and 0.40 × 10-6) approached the threshold of potential carcinogenic risk (1.0 × 10-6). Since these pollutants can continuously accumulate in the soil, the contamination of PCBs, PCNs, and PCDD/Fs in surrounding soil deserves continuous attention.

Rapid Determination of Selected PFAS in Textiles Entering the Waste Stream.

Due to new European legislation, products entering the waste stream containing some perfluoro alkyl substances (PFAS) are subject to "low persistent organic pollutant concentration limits". Concentrations of restricted PFAS must be below this limit for them to be legally recycled or disposed of. A rapid extraction and clean-up method was developed for the determination of 21 PFAS in various polymers used in soft furnishings and upholstery. The optimised method used vortexing and ultrasonication in methanol (0.1% NH4OH), followed by a dilution and syringe filter clean-up step. PFAS were subsequently determined via UPLC-TripleTOF/MS. Good recoveries (80-120%) of target analytes were obtained with tall and narrow chromatogram peaks. The method was validated using control matrix samples spiked with target analytes. Repeated measurements of concentrations of target compounds showed good agreement with the spiked concentrations demonstrating good accuracy and precision. The resultant extracts provided low noise levels resulting in low limits of quantification ranging from 0.1 to 0.4 mg/kg. The developed method was applied successfully to real consumer products and it provided various advantages over traditional methods, including a substantially reduced analysis time, consumables and solvent consumption, and a high sample throughput which is critical to comply with implemented and proposed legislation.

Occurrence and risks of 23 tire additives and their transformation products in an urban water system

Tire wear particles (TWPs) enter road surface with the friction between tires and road surfaces. Under the volatilization, leaching, and transformation action on TWPs by sunlight and rain, tire additives are released into urban water systems, such as surface rainfall runoff, wastewater treatment plants (WWTPs), receiving surface waters, and drinking water treatment plant (DWTP). In this study, we investigated the occurrence of 23 tire additives and their transformation products in the urban water system of the Pearl River Delta region, South China. Nineteen target compounds were detected in the surface runoff, with 1,3-Diphenylguanidine (DPG) showing highest maximum concentration of 58780 ng/L. Benzothiazole and its transformation products are detected at the frequency of 100 % with the total concentrations of 480–42160 ng/L. The antioxidant derivative N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone (6PPD-Q) was also detected up to 1562 ng/L, which was considerably higher than that of the parent compound 6PPD (the maximum concentration of 7.52 ng/L). Eleven and 8 compounds were detected in WWTPs influents and effluents, respectively, with removal rates of − 62–100 %. Seventeen compounds were detected in the receiving Zhujiang and Dongjiang rivers, while 9 compounds were detected in drinking water sources and DWTP samples. Road runoff, with total concentrations of target compounds up to 79200 ng/L, is suggested as the main non-point source for receiving rivers, while WWTPs effluents are the point sources due to incomplete removal of target compounds after accepting the initial runoff. 6PPD-Q and other 10 compounds displayed median to high ecological risks in surface waters, and the human daily intake of tire additives was estimated to be 2.63 × 10−8-3.16 × 10−5 mg/(kg d) via drinking water. This is the first report of the 6PPD-Q and 1,3-Diphenylurea levels in surface waters in China.

Determination of aspirin in municipal wastewaters of Nur-Sultan City, Kazakhstan

The presence of aspirin in the municipal wastewater of Nur-Sultan city, Kazakhstan, was studied in this research. Aqueous phase samples were collected before any treatment [1] and in the end of treatment process of Nur-Sultan wastewater treatment plant [2]. The study was conducted from April to December 2021. The concentrations of target compound were measured using high-pressure liquid chromatography (HPLC).The obtained results showed that the concentration of aspirin was generally higher than those reported in the literature. For instance, influent and effluent concentrations of aspirin were equal to 42.8 – 60.4 ppb and 1.4 – 6.5 ppb, respectively (October – December period). The removal of aspirin by wastewater treatment process was equal to 50 - 90.2%. Aspirin was not detected in the spring-summer period of 2021. This could be due to usage of aspirin as a medicine for the treatment and prevention of seasonal flu in the autumn-winter period by the population of the city of Nur-Sultan. Currently, our research team is working on investigation of other potential contaminants of emerging concern in municipal wastewaters of Nur-Sultan city and on treatment methods that could efficiently remove the contaminants of emerging concern.

Enhancement of bioactive compounds in baby leaf Amaranthus tricolor L. using short-term application of UV-B irradiation

Baby-leaf vegetables are a trade name for leafy vegetables sold as leaves with petioles at the seedling stage. Amaranth (Amaranthus tricolor L.) is a nutritious baby-leaf vegetable containing many bioactive compounds. The effects of short-term ultraviolet B (UV–B) treatments on the growth and quality of baby leaf amaranth were studied, including the conditions of a 24-h recovery period after irradiation, and different irradiation intensities (3.0–9.0 W m−2), irradiation periods (4–16 h), and cumulative energies (130–170 kJ m−2). A recovery period experiment was conducted to observe the changes in the growth and quality of leaves at 0 and 24 h after UV-B irradiation. The results showed that the concentrations of phenolic compounds, flavonoids, anthocyanin, and ascorbic acid in the leaves, as well as the leaf antioxidant capacity increased 24 h after UV-B irradiation. Increases in target compound concentrations and antioxidant capacity without negative growth and appearance effects were observed in leaves irradiated with UV-B at 3, 6, and 9 W m−2 for irradiation periods of 12 and 16, 8 and 12, and 4 h, respectively. The highest bioactive compound concentration was found in leaves irradiated with UV-B at 6 W m−2 for 7 h (cumulative energy: 150 kJ m−2). It was concluded that UV-B irradiation at 6 W m−2 with a cumulative energy of 150 kJ m−2 and a 24 h post-irradiation recovery period could be an appropriate treatment to increase bioactive compounds in baby leaf amaranth without causing appearance abnormalities.

Development of a needle trap device packed with the Schiff base network-1/single-walled carbon nanotube for sampling phenolic compounds in air

This paper introduced needle traps filled with the new Schiff base network-1/single-walled carbon nanotube (SNW-1/SWCNT) adsorbent for sampling and analyzing phenolic compounds (phenol, 3-chlorophenol, o-cresol, and p-cresol) in air. In this perusal, the SNW-1/SWCNT adsorbent was synthesized and packaged using a 22-gauge spinal needle. This approach was first examined inside the laboratory and then applied in the field for real sampling. A 3-inlet container was placed on a heater at a specific temperature to produce different concentrations of phenolic compounds. The response surface methodology and central composite design methods were used to evaluate the desorption and breakthrough volume parameters of needle trap device packed with SNW-1/SWCNT. The Limit of detection and limit of quantitation values of this technique were 0.002–0.011 ng/ml and 0.008–0.037 ng/ml, respectively, indicating that the proposed sampler had very high sensitivity. The maximum response of the peak area was obtained at the extraction temperature of 270 °C and the extractions time of 5 min. The current technique was compared to the NIOSH-2546 method, and an R2 of 0.9812 was obtained between the two methods. The proposed method was used to determine the concentration of target compounds in the air of a plastic factory. The results showed that the concentration was less than the threshold limit values for phenolic compounds. SNW-1/SWCNTs have selectivity and the proposed method is a one-step procedure for analyzing phenolic compounds from the air.

Insights into a packed bubble column for removal of several ozone-persistent TrOCs by ozonation: removal kinetics, energy efficiency and elimination prediction

Ozonation is an efficient method to remove trace organic contaminants (TrOCs) from (waste)water. However, high ozone dose requirement and energy consumption are still limiting its wider application for ozone-persistence TrOCs elimination. In this study, a packed bubble column is designed to enhance the ozone gas-liquid mass transfer and consequentially improve ozone and hydroxyl radical (OH) exposures. An increase of 5–31% removal for five selected ozone-persistence TrOCs was observed in the packed bubble column in comparison to an unpacked bubble column under the same experimental settings. The energy consumption (EEO) for 90% TrOCs removal in the packed column was in range of 0.99–2.76 kWh/m3, which was 5–48% decrease after the use of packing materials. A kinetics-based approach based on the correlation between the concentration of target compounds, the second order reaction rate constants of these compounds with ozone and OH and the ozone and OH exposures was used to predict TrOCs removal. The predicted removal was consistent the measured removal, indicating that this prediction approach can be applied in packed system.

Several typical endocrine-disrupting chemicals in human urine from general population in China: Regional and demographic-related differences in exposure risk

Endocrine-disrupting chemicals (EDCs) are ubiquitous in the environment, and human exposure to these pollutants has caused great public concern. Five groups of EDCs, including parabens, antimicrobials (triclosan (TCS) and triclocarban (TCC)), bisphenols (BPs), tetrabromobisphenol A and its alternatives (TBBPAs), and benzophenones, in urines of general populations from three cities with different economic levels in China were determined simultaneously to evaluate the coexposure levels of such chemicals. The total concentration of target compounds was approximately two times higher in the urines from Chengdu (a first-tier city; geometric mean: 2.50 μg/L) than that from Nantong (a second-tier city; 1.34 μg/L), and was one order of magnitude higher than that from Shehong (a fifth-tier city; 0.73 μg/L). Urinary target compounds were significantly correlated with gender, age, body mass index (BMI), education level, occupation, and diet. The estimated daily intakes of target chemicals ranged from 0.002 (benzophenones) to 10.2 µg/kg-bw/day (parabens). The exposure estimate showed that females were more vulnerable to exposure to these EDCs. This study profiles the regional and demographic-related differences in the concentrations and exposure risks of several typical EDCs in urines from general populations in three cities with different economic levels in China.