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Se Pu = Chinese Journal of... Dec 2023The complex matrix of soil samples and low extraction efficiency of aniline compounds limit many methods developed for detecting aniline and benzidine compounds in soil....
The complex matrix of soil samples and low extraction efficiency of aniline compounds limit many methods developed for detecting aniline and benzidine compounds in soil. In this study, a rapid and sensitive method based on gas chromatography-mass spectrometry was developed for the simultaneous determination of 14 aniline and benzidine compounds in soil. The collected soil samples were sealed with 5% sodium sulfite solution and refrigerated to inhibit the oxidation of the target compounds for up to 7 d. The extraction efficiencies of accelerated solvent extraction and oscillating dispersion extraction were compared, and the recovery of accelerated solvent extraction was found to be unsuitable. Hence, three-phase oscillating dispersion extraction was adopted. A certain amount of alkaline aqueous solution was added to the test system during extraction to improve the extraction efficiency because aniline and benzidine compounds are weakly alkaline substances. When the pH of the extracted water phase was greater than 12, relatively good recoveries were obtained. Next, a mixed solvent of ethyl acetate-methylene chloride (1∶4, v/v) was added to extract the target compounds via oscillation for 20 min. The solid phase was discarded via centrifugation, and the aqueous and organic phases were transferred to a liquid separation funnel for further separation. Finally, the organic phase was retained. This pretreatment process prevents the co-extraction of acidic compounds or other impurities, thereby enhancing the purification ability of the method. Solid phase extraction (SPE) is generally recommended for soil extraction and purification. A preliminary test showed that compared with other columns, the Florisil SPE column could better retain the target substances and exhibited higher elution efficiency. After purification, the organic phase was concentrated to 1 mL using a nitrogen blower. The analytes were analyzed by gas chromatography-mass spectrometry using a capillary column (DB-35MS, 30 m×0.25 mm×0.25 μm). The temperature program was optimized to separate the target compounds at the baseline. Specifically, the initial oven temperature was set to 60 ℃, held for 2 min, increased to 130 ℃ at a rate of 5 ℃/min, increased to 300 ℃ at a rate of 30 ℃/min, and held for 4 min. The injector and ion source temperatures were 250 and 300 ℃, respectively. Aniline-d and acenaphthene-d were used as the internal standards for quantification. The effects of antioxidant addition, extraction solvent type, salting out, and other factors on extraction efficiency were investigated. The results showed that the method performed well under the optimized experimental conditions when actual soils were used as real sample matrices. The accuracy and precision of the proposed method were verified. A total of 14 aniline and benzidine compounds demonstrated good linearities in the range of 0.5-100 mg/L. The method detection limits (MDLs) ranged from 0.02 to 0.07 mg/kg, and the limits of quantification (LOQs) ranged from 0.08 to 0.28 mg/kg. The target compounds were spiked at contents of 1 and 10 mg/kg. The spiked recoveries of the 14 targets in actual soils were 62.9%-101%, and the relative standard deviations (RSDs) of six precision tests were 3.8%-10.3%. The proposed method effectively inhibited the oxidation of aniline and benzidine compounds during extraction, and the target compounds exhibited high recoveries and good stabilities in the presence of three phases. Moreover, the operating procedure was simple and easy to implement. The proposed method was applied to the soil collected from an industrial enterprise in Jiangsu province that was suspected to be contaminated with aniline, and two aniline compounds were detected. The developed method requires a small sample size, and the preservation step is simple and effective. In addition, it can be applied to various types of actual soils. The method meets the requirements of current soil pollution risk control standards for aniline and benzidine compounds in soils.
PubMed: 38093543
DOI: 10.3724/SP.J.1123.2023.01002 -
RSC Advances Dec 2023Gas sensors are used to detect gas components in human breath to diagnose diseases, such as cancers. However, choosing suitable two-dimensional materials for gas sensors...
Gas sensors are used to detect gas components in human breath to diagnose diseases, such as cancers. However, choosing suitable two-dimensional materials for gas sensors is a challenge. Germanene can be a good candidate because of its outstanding electronic and structural properties. Based on the density functional theory calculations with various schemes, such as PBE + vdW-DF2, HSE06 + PBE, and HSE06 + vdW-DF2, we elucidated the structural and electronic properties of germanene substrates (perfect, vacancy-1, and vacancy-2) while adsorbing hepatocellular carcinoma-related volatile organic compounds (VOCs), , acetone, 1,4-pentadiene, methylene chloride, phenol, and allyl methyl sulfide. These gases have been selected for investigation because of their most frequent occurence in diagnosing the disease. We found that vacancy substrates enhanced the adsorption strength of the VOCs compared to the perfect one, where the phenol adsorbed most strongly and exhibited the most profound influence on the structural deformation of the substrates over the other VOCs. Besides, the adsorbed VOCs significantly modified the energy bandgap of the considered germanene substrates. In particular, the gases, except allyl methyl sulfide, vanished the bandgap of the vacancy-1 germanene and converted this substrate from a semiconductor to a metal, while they widened the bandgap of the vacancy-2 structure compared to the isolated case. Therefore, the perfect and vacancy-2 germanene sheets could maintain their semiconducting state upon gas adsorption, implying that these substrates may be suitable candidates for gas sensing applications. The nature of the interaction between the VOCs and the germanene substrates is a physical adsorption with a weak charge exchange, which mainly comes from the contribution of the p orbital of the VOCs and the p orbital of Ge.
PubMed: 38090092
DOI: 10.1039/d3ra05927h -
F1000Research 2022Medicinal plants are potential resources for isolating drug candidates. Various plants have been reported to possess pharmacological effects including anti-hepatitis C...
Medicinal plants are potential resources for isolating drug candidates. Various plants have been reported to possess pharmacological effects including anti-hepatitis C activities. The current study examined the anti-hepatitis C virus (HCV) activities of extracts in solvents with various polarities and further evaluated the mechanism of action of the extracts using Western blotting and combination treatment models. The leaves of were extracted in two phases, first in ethanol and then in solvents with different polarities (n-hexane, dichloromethane, and methanol). HCV-infected Huh7it-1 cells were treated with the extracts at concentrations of 0.01, 0.1, 1, 10, 50, and 100 µg/mL. The results revealed the strong anti-HCV activities of the extracts. The 50% inhibition concentrations (IC s) of the ethanol, n-hexane, dichloromethane and methanol extracts were of 4.6 ± 0.3, 2.9 ± 0.2, 0.2 ± 0.3, and 2.8 ± 0.2 μg/mL, respectively, and no cytotoxic effect was detected. These extracts displayed stronger effects than the positive control ribavirin. The mode of action of the ethanol extract was evaluated at 30 µg/mL, revealing that the inhibitory effect was stronger on the post-entry step than on the entry step. Western blotting revealed that the extracts decreased NS3 protein expression, indicating that virus replication was suppressed. Further evaluation illustrated that combined treatment with the ethanol extract enhanced the anti-viral activity of simeprevir. These results indicated that leaves could represent sources of anti-HCV agents.
Topics: Plant Extracts; Acacia; Hepacivirus; Methanol; Methylene Chloride; Solvents; Hepatitis C; Ethanol
PubMed: 38046541
DOI: 10.12688/f1000research.124947.3 -
Journal of Chromatography. B,... Dec 2023Carotenoids, such as lycopene and β-carotene, have been widely recognized for their antioxidant properties and potential health benefits. Accurate quantification of...
Carotenoids, such as lycopene and β-carotene, have been widely recognized for their antioxidant properties and potential health benefits. Accurate quantification of carotenoids in plant extracts is essential for nutritional assessment, quality control, and research investigations. This study introduces an innovative method for quantifying lycopene and β-carotene, in plant extracts and aims to bridge the gap between complex and expensive carotenoid quantification techniques and the need for accessible methods that can be widely adopted. The primary difference between HPLC and HPTLC lies in the medium used for separation. HPLC employs a liquid phase within columns, while HPTLC utilizes a thin layer of adsorbent on a plate. This distinction impacts factors like equipment, cost, and analysis time. The VisionCats software, combined with the CAMAG Visualizer-2, allows the semi-quantification of metabolites using an image-based evaluation method enabling the simultaneous assessment of qualitative and semi-quantitative information from the HPTLC images. Sample preparation involves washing and drying the vegetal material, followed by dichloromethane extraction. HPTLC analysis is performed using the CAMAG Advanced Herbal System, and the validation studies include establishing calibration curves and determining the detection threshold and minimum quantification threshold for lycopene and β-carotene. Specificity and precision were evaluated to ensure accurate identification and repeatability of the method. Data analysis involves selecting the regression method based on the nature of the data and assessing the goodness of fit using the R2 value. The results showed distinct peaks corresponding to lycopene and β-carotene in the chromatograms of the plant extract samples. The visualizer-based method demonstrates good specificity and precision, with no interfering peaks observed and low relative standard deviation. The method shows promising results regarding specificity, precision, and reliability. It has the potential for broader implementation in carotenoid research and rapid monitoring of carotenoid content in various agricultural and food products, particularly in resource-limited settings. Further optimization and validation on a wider range of samples would enhance the applicability of this method in carotenoid research. Sample preparation involves washing and drying the vegetal material, followed by dichloromethane extraction. HPTLC analysis is performed using the CAMAG Advanced Herbal System, and the validation studies include establishing calibration curves and determining the detection threshold and minimum quantification threshold for lycopene and β-carotene. Specificity and precision were evaluated to ensure accurate identification and repeatability of the method. Data analysis involves selecting the regression method based on the nature of the data and assessing the goodness of fit using the R2 value. The results showed distinct peaks corresponding to lycopene and β-carotene in the chromatograms of the plant extract samples. The visualizer-based method demonstrates good specificity and precision, with no interfering peaks observed and low relative standard deviation. The method shows promising results regarding specificity, precision, and reliability. It has the potential for broader implementation in carotenoid research and for rapid screening and monitoring of carotenoid content in various agricultural and food products, particularly in resource-limited settings. Further optimization and validation on a wider range of samples would enhance the applicability of this method in carotenoid research.
Topics: Lycopene; beta Carotene; Reproducibility of Results; Methylene Chloride; Solanum lycopersicum; Carotenoids; Plant Extracts
PubMed: 38035540
DOI: 10.1016/j.jchromb.2023.123929 -
Journal of Chromatography. A Jan 2024The concentration of carbazoles in highly mature crude oil is quite low, making it challenging to separate carbazole compounds for the gas chromatography-mass...
The concentration of carbazoles in highly mature crude oil is quite low, making it challenging to separate carbazole compounds for the gas chromatography-mass spectrometry (GC-MS) detection. This study presents a small-scale column chromatography method for separating carbazoles from highly mature crude oil using silica gel as a solid phase adsorbent and a Pasteur pipette as a separation device. The carbazole-rich crude oil from the Pearl River Mouth Basin was selected to explore the impact of reagent polarity and injection mode on the separation of carbazoles. The oil sample was eluted with solvents mixed with different volume proportions of n-hexane and dichloromethane and each eluted fraction was collected for GC-MS testing. The results indicated that increasing the reagent polarity caused the aromatic hydrocarbons and carbazole compounds in crude oil to be eluted sequentially. Most aromatic compounds in the crude oil could be selectively eluted using a reagent polarity ratio of 9:1 (V: V), with no carbazole compounds. A significant amount of carbazole compounds were eluted in the polar segments of 8:2-6:4, with the eluted carbazoles concentration accounting for more than 98 % of the total concentration. Moreover, the concentration and recovery of carbazoles eluted by direct injection mode were about 10 % higher than those after adsorption by silica gel. The standard deviation of the parameter ratio for the separated carbazole compounds in the three groups of repeatable parallel experiments was less than 0.2 %. Our method is superior to traditional two-step method and C column method in separation efficiency and damage to human body. This method can be applied to both highly mature crude oil and other kinds of oils including biodegradable oil. It could be a versatile method for the carbazoles separation and provide technical support in unveiling the geochemical implications of these compounds in complex areas.
Topics: Humans; Petroleum; Silica Gel; Methylene Chloride; Gas Chromatography-Mass Spectrometry; Oils; Carbazoles
PubMed: 38029659
DOI: 10.1016/j.chroma.2023.464536 -
RSC Advances Nov 2023A new, straightforward spectrofluorimetric approach with high sensitivity was established for determining midodrine hydrochloride based on derivatizing this drug through...
Utility of dansyl chloride for the establishment of a sensitive spectrofluorimetric approach for estimating midodrine hydrochloride: application to content uniformity testing.
A new, straightforward spectrofluorimetric approach with high sensitivity was established for determining midodrine hydrochloride based on derivatizing this drug through its reaction with 5-(dimethylamino)naphthalene-1-sulfonyl chloride (dansyl chloride). The highly fluorescent product was extracted with methylene chloride, and then its emission was measured at 532 nm after excitation at 339 nm. The reaction was conducted in aqueous medium containing 0.1 M borate buffer (pH 8.2). The results showed that the proposed method is sensitive with high linearity in the range from 0.1 to 3 μg mL. The lower limits of detection and quantitation were 29 and 88 ng mL, respectively. Furthermore, the proposed approach was analytically assessed by applying the ICH guidelines. The suggested approach was effectively utilized for the estimation of the medicine in its marketable tablet formulations with excellent recovery and without any interfering effect from excipients. Moreover, the presented approach was utilized to test the content uniformity of commercial tablets following the USP guidelines.
PubMed: 38025857
DOI: 10.1039/d3ra06268f -
ACS Omega Nov 2023Gastric problems are often caused by the well-known () bacterium. One of the biggest obstacles to the treatment of infections is increasing the antibiotic resistance....
Gastric problems are often caused by the well-known () bacterium. One of the biggest obstacles to the treatment of infections is increasing the antibiotic resistance. During our search for naturally derived anti- compounds, six major compounds were isolated from the methylene chloride (CHCl) and ethyl acetate (EtOAc) fractions of a that showed anti- activity. Three anthraquinones and three anthraquinone glucosides were identified as the major chemical constituents of the CHCl and EtOAc fractions, respectively. The chemical structures were identified to be emodin (), chrysophanol (), physcion (), emodin-8--β-d-glucoside (), chrysophanol-8--β-d-glucoside (), and physcion-8--β-d-glucoside () by UV, H NMR, C NMR, and mass spectrometry. Anti- activity, including the minimum inhibitory concentration (MIC) value of each compound, was evaluated against two strains. All isolates exhibited anti- activity with different potencies, with an MIC value ranging between 3.13 and 25 μM. However, some variations were found between the two strains. While compound displayed the most potent antibacterial activity with an MIC value of 8.60 μM and an MIC value of 15.7 μM against strain 51, compound exhibited the most potent inhibitory activity against strain 43504. The two compounds also showed moderate urease inhibitory activity, with compound demonstrating activity higher than that of compound . Furthermore, a molecular docking study revealed the high binding ability of compounds and to the active site of urease. The present study suggests that the six anthraquinones isolated from with the whole parts of this plant may be natural candidates for the treatment of infection. Further studies are required to determine the exact mechanism of action and to evaluate safety issues in the human body.
PubMed: 38024697
DOI: 10.1021/acsomega.3c05282 -
International Journal of Biological... Jan 2024In response to the new concept of green sustainability, it is necessary to expand the functionality of bio-based natural fibers (such as cotton fabrics) to replace...
In response to the new concept of green sustainability, it is necessary to expand the functionality of bio-based natural fibers (such as cotton fabrics) to replace fabrics made from fossil fuels. One potential way of achieving this is through the use of phosphorus, boron and nitrogen based organic flame retardants. This article designs a special flame retardant system with high efficiency, high durability, and enhanced fabric strength. An "H" shaped flame retardant (TBSA) is synthesized using hydroxyethyl methylene phosphate, pentaerythritol diborate, and cyanuric chloride. After simple treatment, flame retardant fabric (TBSA/Cotton) is obtained, with a LOI value of 48.8 %. Self extinguishing is completing in the vertical flame test. The high FR efficiency reflects the progressiveness of multi flame retardant elements. It is worth noting that TBSA/Cotton exhibits excellent durability and improves the strength of the fabric. This is attributed to the covalent bonding between the "H" type flame retardant and multiple cellulose molecules, which compensates for the cracks and holes at the submicroscopic scale of natural cellulose and weakens the molecular slip effect. The research results of this article provide a good opportunity for the development of biomass cellulose flame retardant materials.
Topics: Flame Retardants; Textiles; Hydrogen; Protons; Cellulose
PubMed: 38016602
DOI: 10.1016/j.ijbiomac.2023.128457 -
Chemistry & Biodiversity Dec 2023This study examined the effects of methanol extract and its sub-extracts from Epilobium angustifolium on α-glucosidase and α-amylase activity. Secondary metabolites...
Phytochemical Analysis and Evaluation of Genotoxic, Antigenotoxic Effects in Bacterial Models, and Hypoglycemic Activity of Epilobium angustifolium L. with Bioguided Isolation of Active Compounds.
This study examined the effects of methanol extract and its sub-extracts from Epilobium angustifolium on α-glucosidase and α-amylase activity. Secondary metabolites and amino acids were quantified using LC-MS/MS. Dichloromethane sub-extract displayed the highest activity and was chosen for further investigation. Despite the widespread use of E. angustifolium, genotoxicity studies were conducted to assess its safety. Dichloromethane significantly inhibited α-glucosidase (IC =17.340 μg/mL), making it approximately 293 times more effective than acarbose. Six known compounds, including gallic acid (1), a mixture of quercetin-3-O-α-galactoside (2a) and quercetin-3-O-α-glucoside (2b), quercetin-3-O-α-glucuronic acid (3), quercetin-3-O-α-rhamnoside (4), and kaempferol-3-O-α-rhamnoside (5) were identified. Quercetin-3-O-α-rhamnoside exhibited the highest inhibition of α-glucosidase (IC =1735±85 μM), making it 3.70 times more effective than acarbose. Dichloromethane also showed significant antigenotoxic activity against mutagenesis induced by NaN3, 9-AA, 4-NPD, and MNNG. Gallic acid was found in the highest abundance (13253.6931 ng/mL) in the methanolic extract. Furthermore, L-Aspartic acid was the most concentrated amino acid (363.5620 nmol/mL) in the methanolic extract.
Topics: Quercetin; Epilobium; Hypoglycemic Agents; Acarbose; alpha-Glucosidases; Chromatography, Liquid; Methylene Chloride; Plant Extracts; Tandem Mass Spectrometry; Gallic Acid; Phytochemicals
PubMed: 37997279
DOI: 10.1002/cbdv.202300922 -
Inorganic Chemistry Jan 2024There is unceasing interest toward transformations of phosphine derivatives, which are facilitated by transition metals. We report a facile Pd(II)- and Pt(II)-assisted...
There is unceasing interest toward transformations of phosphine derivatives, which are facilitated by transition metals. We report a facile Pd(II)- and Pt(II)-assisted P-C bond cleavage in a luminescent 2-phenylbenzothiazole-based α-methylaminophosphine (, ). Specifically, reactions between and [M(COD)Cl] (M = Pd, Pt; COD = cycloocta-1,5-diene) in different solvents (methylene chloride, acetonitrile, pyridine, toluene) resulted in the formation of PPh, captured either as a bridging ligand in binuclear complexes with a {M(PPh)} moiety or as an adduct to COD in [Pt(PPhCOD)Cl]. The heterocyclic part transforms to annulated species with a 1,2-dihydroquinazoline cycle formed. In the presence of pyridine as a base, annulated form destabilizes and undergoes reverse cyclization transforming to deprotonated form. Quantum-chemical density functional theory (DFT) calculations predict that a crucial step in the reactions involves proton transfer from the N atom of the amino group of to a neighboring molecule. A combination of high photophysical sensitivity of toward its immediate environment and rich structural capabilities in assembling () pairs in different crystal packings in a family of phases with the general formula ()[M(PPh)Cl] allows one to fine-tune the luminescence properties of the latter. The results were rationalized as a variation of π-π intercationic spacings, which tunes the degree of excited-state charge transfer between cations. As a result, compounds with relatively short interplanar π-π-separation between the cations show a stronger charge-transfer-mediated bathochromic shift.
PubMed: 37988741
DOI: 10.1021/acs.inorgchem.3c03271