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1.
J UOEH ; 46(1): 9-16, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38479880

RESUMO

This study investigated the permeation resistance of chemical protective gloves made of laminate film comprising nylon, ethylene-vinyl alcohol copolymer (EVOH), and other materials against different chemical substances to examine their usability in different work processes. The permeation resistance of the chemical protective glove was tested using the Japanese Industrial Standards (JIS) test method against twelve substances: acetone, acetonitrile, dichloromethane, ethyl acetate, n-hexane, methanol, tetrahydrofuran, toluene, 2-propanol, 1-butanol, 1,4-diethylene dioxide, and ethanol. After 480 min, no substance, except for methanol and ethanol, permeated at a standard permeation rate of 0.1 µg/cm2/min. Methanol and ethanol showed permeation at 1 min and 30 min elapsed, respectively. Hence, the gloves tested in this study exhibited permeation resistance to various chemical substances, and can thus be used in many work processes. Some film materials have short permeation time against certain chemical substances, but the chemical protective gloves tested in this study can be used at work sites, such as manufacturing sites, that require permeation resistance to different chemical substances.


Assuntos
Luvas Protetoras , Exposição Ocupacional , Metanol , Etanol/química , Acetona/química , Tolueno/química
2.
Soft Matter ; 20(3): 495-510, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38088053

RESUMO

Jellyfish as a potential sustainable food material has recently gained increasing interest. However, with their soft gel-like texture and easy spoilage, it remains challenging to achieve desirable edible structures from jellyfish. The culinary preparation of jellyfish is a complex process and extends beyond conventional cooking methods. In this study, we investigate the transformation of jellyfish into crispy-like structures by manipulating their microstructural and mechanical properties through a solvent-based preparation. The study focuses on the use of "poor solvents", namely ethanol and acetone, and employs rheology measurements and quantitative microscopy techniques to analyze the effects of these solvents on the mechanical properties and microstructure of jellyfish. Our findings reveal that both ethanol and acetone lead to a significant increase in jellyfish hardness and deswelling. Notably, a micro-scale network is formed within the jellyfish matrix, and this network is then mechanically reinforced before a crispy-like texture can be obtained. Our study points to solvent polarity as also being a crucial factor for creating these effects and determines an upper polarity limit in the range of 12.2-12.9 MPa1/2 for added solvents, corresponding to approximately 60% of added ethanol or 70% of added acetone. Our study highlights that solvent-based preparation serves as a "reverse cooking" technique, where mechanical modification rather than traditional softening mechanisms are employed to stabilize and strengthen the microstructures and fibers of jellyfish. By elucidating the underlying mechanisms of solvent-induced stabilization, our findings may facilitate the development of innovative and sustainable culinary practices, paving the way for broader applications of jellyfish and other soft edible materials in the gastronomic landscape.


Assuntos
Acetona , Etanol , Solventes/química , Acetona/química , Etanol/química
3.
Nature ; 626(7999): 542-548, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38109940

RESUMO

The success of colloidal semiconductor nanocrystals (NCs) in science and optoelectronics is inextricable from their surfaces. The functionalization of lead halide perovskite NCs1-5 poses a formidable challenge because of their structural lability, unlike the well-established covalent ligand capping of conventional semiconductor NCs6,7. We posited that the vast and facile molecular engineering of phospholipids as zwitterionic surfactants can deliver highly customized surface chemistries for metal halide NCs. Molecular dynamics simulations implied that ligand-NC surface affinity is primarily governed by the structure of the zwitterionic head group, particularly by the geometric fitness of the anionic and cationic moieties into the surface lattice sites, as corroborated by the nuclear magnetic resonance and Fourier-transform infrared spectroscopy data. Lattice-matched primary-ammonium phospholipids enhance the structural and colloidal integrity of hybrid organic-inorganic lead halide perovskites (FAPbBr3 and MAPbBr3 (FA, formamidinium; MA, methylammonium)) and lead-free metal halide NCs. The molecular structure of the organic ligand tail governs the long-term colloidal stability and compatibility with solvents of diverse polarity, from hydrocarbons to acetone and alcohols. These NCs exhibit photoluminescence quantum yield of more than 96% in solution and solids and minimal photoluminescence intermittency at the single particle level with an average ON fraction as high as 94%, as well as bright and high-purity (about 95%) single-photon emission.


Assuntos
Desenho de Fármacos , Ligantes , Nanopartículas Metálicas , Pontos Quânticos , Acetona/química , Álcoois/química , Ânions , Compostos de Cálcio/química , Cátions , Coloides/química , Chumbo , Medições Luminescentes , Espectroscopia de Ressonância Magnética , Nanopartículas Metálicas/química , Simulação de Dinâmica Molecular , Óxidos/química , Fosfolipídeos/química , Pontos Quânticos/química , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Titânio/química
4.
PLoS One ; 18(7): e0288102, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37418444

RESUMO

Plate-based proteomic sample preparation offers a solution to the large sample throughput demands in the biotechnology field where hundreds or thousands of engineered microbes are constructed for testing is routine. Meanwhile, sample preparation methods that work efficiently on broader microbial groups are desirable for new applications of proteomics in other fields, such as microbial communities. Here, we detail a step-by-step protocol that consists of cell lysis in an alkaline chemical buffer (NaOH/SDS) followed by protein precipitation with high-ionic strength acetone in 96-well format. The protocol works for a broad range of microbes (e.g., Gram-negative bacteria, Gram-positive bacteria, non-filamentous fungi) and the resulting proteins are ready for tryptic digestion for bottom-up quantitative proteomic analysis without the need for desalting column cleanup. The yield of protein using this protocol increases linearly with respect to the amount of starting biomass from 0.5-2.0 OD*mL of cells. By using a bench-top automated liquid dispenser, a cost-effective and environmentally-friendly option to eliminating pipette tips and reducing reagent waste, the protocol takes approximately 30 minutes to extract protein from 96 samples. Tests on mock mixtures showed expected results that the biomass composition structure is in close agreement with the experimental design. Lastly, we applied the protocol for the composition analysis of a synthetic community of environmental isolates grown on two different media. This protocol has been developed to facilitate rapid, low-variance sample preparation of hundreds of samples and allow flexibility for future protocol development.


Assuntos
Acetona , Proteômica , Acetona/química , Proteômica/métodos , Proteínas , Indicadores e Reagentes
5.
Bioresour Technol ; 382: 129175, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37187333

RESUMO

This work demonstrated that bio-jet fuels can be directionally prepared from bagasse (a typical lignocellulose biomass) by integrating bio- and chemical catalysis reaction processes. This controllable transformation started with the preparation of acetone/butanol/ethanol (ABE) intermediates through the enzymolysis and fermentation of bagasse. Pretreatment of bagasse by deep eutectic solvent (DES) promoted the enzymatic hydrolysis and fermentation because it destroyed the structure of biomass and remove lignin in lignocellulose. Subsequently, the selective catalytic conversion of sugarcane derived ABE broth to jet range fuels was achieved through an integrated process: ABE dehydration to light olefins over the HSAPO-34 catalyst and olefin polymerization to bio-jet fuels over the Ni/HBET catalyst. The dual catalyst bed synthesis mode improved the selectively of bio-jet fuels. High selectivity of jet range fuels (83.0 %) and high conversion of ABE (95.3 %) were obtained by the integrated process.


Assuntos
Acetona , Alcenos , Fermentação , Acetona/química , Polimerização , Biomassa , Etanol/química , Butanóis , 1-Butanol
6.
Environ Res ; 229: 115931, 2023 07 15.
Artigo em Inglês | MEDLINE | ID: mdl-37076034

RESUMO

A nano-enabled low-trace monitoring system for acetone has the potential to revolutionize breath omics-based non-invasive diagnosis of human diabetes and environmental monitoring technologies. This unprecedented study presents the state-of-the-art facile and economic template-assisted hydrothermal route to fabricate novel CuMoO4 nanorods for room temperature breath and airborne acetone detection. Physicochemical attribute analysis reveals the formation of crystalline CuMoO4 nanorods with diameters ranging from 90 to 150 nm, and an optical band gap of approximately 3.87 eV. CuMoO4 nanorods-based chemiresistor demonstrates excellent acetone monitoring performance, with a sensitivity of approximately 33.85 at a concentration of 125 ppm. Acetone detection is rapid, with a response time of 23 s and fast recovery within 31 s. Furthermore, the chemiresistor exhibits long-term stability and selectivity towards acetone, compared to other interfering volatile organic compounds (VOCs) commonly found in human breath such as ethanol, propanol, formaldehyde, humidity, and ammonia. The linear detection range of acetone from 25 to 125 ppm achieved by the fabricated sensor is well-suited for human breath-based diagnosis of diabetes. This work represents a significant advancement in the field, as it offers a promising alternative to time-consuming and costly invasive biomedical diagnostics, with the potential for application in cleanroom facilities for indoor contamination monitoring. The utilization of CuMoO4 nanorods as sensing nanoplatform opens new possibilities for the development of nano-enabled, low-trace acetone monitoring technologies for non-invasive diabetes diagnosis and environmental sensing applications.


Assuntos
Diabetes Mellitus , Nanotubos , Compostos Orgânicos Voláteis , Humanos , Acetona/análise , Acetona/química , Testes Respiratórios , Diabetes Mellitus/diagnóstico , Compostos Orgânicos Voláteis/análise
7.
Molecules ; 28(3)2023 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-36770820

RESUMO

Metal oxide (MOx) gas sensors have attracted considerable attention from both scientific and practical standpoints. Due to their promising characteristics for detecting toxic gases and volatile organic compounds (VOCs) compared with conventional techniques, these devices are expected to play a key role in home and public security, environmental monitoring, chemical quality control, and medicine in the near future. VOCs (e.g., acetone) are blood-borne and found in exhaled human breath as a result of certain diseases or metabolic disorders. Their measurement is considered a promising tool for noninvasive medical diagnosis, for example in diabetic patients. The conventional method for the detection of acetone vapors as a potential biomarker is based on spectrometry. However, the development of MOx-type sensors has made them increasingly attractive from a medical point of view. The objectives of this review are to assess the state of the art of the main MOx-type sensors in the detection of acetone vapors to propose future perspectives and directions that should be carried out to implement this type of sensor in the field of medicine.


Assuntos
Diabetes Mellitus , Compostos Orgânicos Voláteis , Humanos , Acetona/química , Gases/análise , Óxidos/química , Diabetes Mellitus/diagnóstico , Compostos Orgânicos Voláteis/análise
8.
Int J Biol Macromol ; 225: 1449-1461, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36436598

RESUMO

One of the key strategies for valorizing kraft lignin (KL) into value-added products such as bio-based adhesives is to perform solvent fractionation of KL to produce lignin with improved homogeneity. Understanding the structure and properties of fractionated KL will aid in the selection of the best samples for certain applications. In this study, acetone-fractionated KL from softwood and hardwood was characterized to understand its chemical structure, elemental composition, molecular weight, and thermal properties. The results revealed that acetone-insoluble KL (AIKL) fractions from softwood and hardwood have greater molecular weight, polydispersity, glass temperature, carbohydrate content, aliphatic hydroxyl groups, and a variety of native wood lignin side chains. In contrast, acetone-soluble KL (ASKL) fractions have a significantly lower molecular weight and polydispersity, a lower glass-transition temperature, a more condensed structure, more aromatic hydroxyl groups, and fewer native wood lignin side chains. In addition, the ASKL samples demonstrated stronger adhesive force and work of adhesion toward phenol-formaldehyde (PF) and urea-formaldehyde (UF) resins than the AIKL samples, regardless of the lignin source. These findings suggest that ASKL has great potential as a substitute for phenol in PF resins and as a green additive to reinforce UF resins.


Assuntos
Acetona , Lignina , Lignina/química , Acetona/química , Estrutura Molecular , Fenóis , Fenol/química , Formaldeído/química , Adesivos/química
9.
Anal Methods ; 14(44): 4514-4522, 2022 11 18.
Artigo em Inglês | MEDLINE | ID: mdl-36326109

RESUMO

Trace acetone determination in breath can be regarded as a noninvasive method for diagnosis of diabetes. Here, a paper-based CL gas sensor combined with UiO-66 as the preconcentrator was established for sensitive detection of trace acetone in exhaled breath. UiO-66 with excellent adsorption performance and unique water stability was used for the adsorption and enrichment of acetone gas under high humidity conditions in exhaled breath. As acetone can remarkably increase the chemiluminescence (CL) of the 2,4-dinitrophenylhydrazine (DNPH)-potassium permanganate (KMnO4) system, a sensitive CL device based on a paper substrate for trace acetone detection was established and the detection limit was 0.03 ppm. The fabricated method was used to assess the content of trace acetone in exhaled breath with satisfactory recoveries of 90-110%. It is expected to realize the noninvasive determination of acetone for diabetic patients in exhaled breath.


Assuntos
Diabetes Mellitus , Estruturas Metalorgânicas , Humanos , Acetona/química , Testes Respiratórios/métodos , Luminescência , Diabetes Mellitus/diagnóstico
10.
J Am Soc Mass Spectrom ; 33(10): 1982-1989, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36126229

RESUMO

The Paternò-Büchi (PB) reaction is a cycloaddition reaction between a carbon-carbon double bond (C═C) and a photochemically excited carbonyl-containing compound. The constrained ring formed between the C═C bond and the PB reagent is more susceptible to fragmentation by collision-induced dissociation, which facilitates identification of the C═C position within the fatty acyl tails of lipids. Although the original PB reaction using acetone had a low yield of derivatized lipids and therefore a low yield of diagnostic ions, a new generation of PB reagents based on halogenated acetophenones has improved the reaction yield substantially. In this study, we investigated the use of halogenated PB reagents and ion mobility to improve the identification of PB-derivatized lipids by shifting them out of the densely populated lipid region of ion mobility-mass spectrometry (IM-MS) space. Several halogenated PB reagents containing fluorine, chlorine and bromine were investigated for their ability to decrease the collision cross-section (CCS) values of derivatized lipids and yield sufficient intensity for both the derivatized lipid and its diagnostic ions. We found that 4'-chloro-2',6'-difluoroacetophenone (CDFAP) displayed the best performance, with an average decrease in CCS of 4.4% and yield of derivatized lipids and diagnostic ions comparable to the trifluorinated acetophenone reagent proposed by the Xia group. The unique isotope pattern resulting from the chlorine substituent aided in identification of the derivatized lipids and their diagnostic ions, as well. We further demonstrate that derivatization with CDFAP preserves the separation of lipids classes in IM-MS space.


Assuntos
Acetona , Bromo , Acetona/química , Acetofenonas , Carbono/química , Cloro , Flúor , Indicadores e Reagentes , Íons , Isótopos , Lipídeos/química
11.
Anal Chem ; 94(38): 13117-13125, 2022 09 27.
Artigo em Inglês | MEDLINE | ID: mdl-36121000

RESUMO

The evaluation of double bond positions in fatty acyl chains has always been of great concern given their significance in the chemical and biochemical role of lipids. Despite being the foremost technique for lipidomics, it is difficult in practice to obtain identification beyond the fatty acyl level by the sole high-resolution mass spectrometry. Paternò-Büchi reactions of fatty acids (FAs) with ketones have been successfully proposed for pinpointing double bonds in FAs in combination with the collision-induced fragmentation technique. In the present paper, an aza-Paternò-Büchi (aPB) reaction of lipids with 6-azauracil (6-AU) was proposed for the first time for the determination of carbon-carbon double bonds in fatty acyl chains using higher collisional dissociation in the negative ion mode. The method was optimized using free FA and phospholipid analytical standards and compared to the standard Paternò-Büchi reaction with acetone. The introduction of the 6-AU moiety allowed enhancing the ionization efficiency of the FA precursor and diagnostic product ions, thanks to the presence of ionizable sites on the derivatizing agent. Moreover, the aPB derivatization allowed the obtention of deprotonated ions of phosphatidylcholines, thanks to an intramolecular methyl transfer from the phosphocholine polar heads during ionization. The workflow was finally applied for pinpointing carbon-carbon double bonds in 77 polar lipids from an yeast (Saccharomyces cerevisiae) extract.


Assuntos
Acetona , Carbono , Acetona/química , Carbono/química , Ácidos Graxos , Íons , Fosfatidilcolinas , Fosfolipídeos/química , Fosforilcolina , Extratos Vegetais
12.
Small ; 18(42): e2203715, 2022 10.
Artigo em Inglês | MEDLINE | ID: mdl-36058648

RESUMO

Limited by the insufficient active sites and the interference from breath humidity, designing reliable gas sensing materials with high activity and moisture resistance remains a challenge to analyze human exhaled breath for the translational application of medical diagnostics. Herein, the dual sensing and cooperative diagnosis is achieved by utilizing metal-organic frameworks (MOFs) and its derivative. The Fe-MIL-101-NH2 serves as the quartz crystal microbalance humidity sensing layer, which exhibits high selectivity and rapid response time (16 s/15 s) to water vapor. Then, the Co2+ and Ni2+ cations are further co-doped into Fe-MIL-101-NH2 host to obtain the derived Co/Ni/Fe trimetallic  oxides (CoNiFe-MOS-n). The chemiresistive CoNiFe-MOS-n sensor displays the high sensitivity (560) and good selectivity to acetone, together with a lower original resistance compared with Fe2 O3 and NiFe2 O4 . Moreover, as a proof-of-concept application, synergistic integration of Fe-MIL-101-NH2 and derived CoNiFe-MOS-n is carried out. The Fe-MIL-101-NH2 is applied as moisture sorbent materials, which realize a sensitivity compensation of CoNiFe-MOS-n sensors for the detection of acetone (biomarker gas of diabetes). The findings provide an insight for effective utilization of MOFs and the derived materials to achieve a trace gas detection in exhaled breath analysis.


Assuntos
Estruturas Metalorgânicas , Materiais Inteligentes , Humanos , Estruturas Metalorgânicas/química , Óxidos , Acetona/química , Vapor , Cátions , Biomarcadores
13.
Phys Chem Chem Phys ; 24(34): 20491-20505, 2022 Aug 31.
Artigo em Inglês | MEDLINE | ID: mdl-35993356

RESUMO

The detection of volatile organic compounds by gas sensors is of great interest for environmental quality monitoring and the early-stage and noninvasive diagnosis of diseases. Experiments found hexane, toluene, aniline, butanone, acetone, and propanol gases in the exhaled breath of patients suffering from COVID-19, lung cancer, and diabetes. However, no studies are available to systematically elucidate the selectivity of these gases on nanosheets of zinc oxide for chemiresistive and direct thermoelectric gas sensors. Therefore, this work performed the elucidation by studying the electronic, electrical, and thermal properties of the bilayered ZnO nanosheets with polar (0001) and non-polar (112̄0) surfaces under the adsorption of the gases. The interaction between the gases and the nanosheets belongs to two groups: electrostatic attraction and charge exchange. The second one occurs due to the peak resonance of the same type of orbitals between the substrates and the gases along the surface normal and the first one for the other cases. The characteristics of the Seebeck coefficient exhibited distinct selectivity of butanone and acetone.


Assuntos
COVID-19 , Compostos Orgânicos Voláteis , Óxido de Zinco , Acetona/química , Butanonas , Gases , Humanos , Óxido de Zinco/química
14.
Environ Sci Pollut Res Int ; 29(53): 80646-80656, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35723824

RESUMO

The hierarchical porous composites (Beta/Dt) were prepared by secondary growth method using natural diatomite and beta zeolite. Moreover, XRD, SEM, and BET characterize the composite's composition, surface structure, and pore structure. The adsorbability of Beta/Dt was evaluated by adsorption of three common volatile organic compounds (VOCs) of the printing industry: acetone, ethyl acetate, and toluene. The results show that under the optimum preparation condition, the adsorption capacities of the three VOCs on Beta/Dt were about 3.5 times those of pure beta zeolite and 4.7-35.3 times those of diatomite, respectively. It indicates the synergistic adsorption effect between beta zeolite and diatomite. The superior adsorption capacity of Beta/Dt can be attributed to the suitable micropore size, the increase of the diffusion channels, and the chemical adsorption on modification diatomite. The adsorption of acetone, ethyl acetate, and toluene on Beta/Dt conformed to the pseudo-second-order kinetic model. In contrast, adsorption isotherms conformed to the Langmuir model, meaning that both physical and chemical adsorption occurred simultaneously during the adsorption process, and the adsorption belonged to the monolayer adsorption. The chemical adsorption mechanism can be ascribed to the nucleophilic reaction between the three VOCs (acetone, ethyl acetate, and toluene) and Beta/Dt with positive charges resulting from the modification diatomite. Furthermore, the composite could still keep more than 90% of the adsorption capacity of the original adsorbent after five regeneration cycles.


Assuntos
Compostos Orgânicos Voláteis , Zeolitas , Tolueno/química , Adsorção , Zeolitas/química , Acetona/química , Compostos Orgânicos Voláteis/química , Cinética
15.
J Colloid Interface Sci ; 621: 119-130, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35452926

RESUMO

To improve gas sensing performance of SnO2 sensor, a heterostructure constructed by SnO2 and SnSe2 is designed and synthesized via hydrothermal method and post thermal oxidation treatment. The obtained SnSe2/SnO2 composite nanoparticles demonstrate a special core-shell structure with SnO2 nanograins distributed in the shell and mixed SnSe2 and SnO2 nanograins in the core. Owning to the promoted charge transfer effect invited by SnSe2, the sensor based on SnSe2/SnO2 composite nanoparticles exhibit expressively enhanced acetone sensing performance compared to the pristine SnO2 sensor. At the working temperature of 300 °C, the SnSe2/SnO2 composite sensor with optimized composition exhibits superior sensing property towards acetone, including high response (10.77-100 ppm), low theoretical limit of detection (0.354 ppm), high selectivity and good reproducibility. Moreover, the sensor shows a satisfactory sensing performance in trace acetone gas detection under high humidity condition (relative humidity: 70-90%), making it a promising candidate to constructing exhaled breath sensors for acetone detection.


Assuntos
Diabetes Mellitus , Nanopartículas , Acetona/química , Humanos , Reprodutibilidade dos Testes , Compostos de Estanho/química
16.
Molecules ; 27(2)2022 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-35056753

RESUMO

The extract from Entada phaseoloides was employed as active ingredients of natural origin into cosmetic products, while the components analysis was barely reported. Using LC-DAD-MS/qTOF analysis, eleven compounds (1-11) were proposed or identified from acetone extract of E. phaseoloides leaves (AE). Among them, six phenolic compounds, protocatechuic acid (2), 4-hydroxybenzoic acid (3), luteolin-7-O-ß-d-glucoside (5), cirsimaritin (6), dihydrokaempferol (9), and apigenin (10), were isolated by various chromatographic techniques. Protocatechuic acid (2), epicatechin (4), and kaempferol (11) at a concentration 100 µM increased the HaCaT cells viability of the UVB-irradiated cell without any cytotoxicity effect and reduced the expression of COX-2 and iNOS inflammation gene. Moreover, compounds 2 and 4 could have potent effects on cell migration during wound closure. These results suggest that compounds 2, 4, and 11 from AE have anti-photoaging properties and could be employed in pharmaceutical and cosmeceutical products.


Assuntos
Fabaceae/química , Queratinócitos/efeitos dos fármacos , Fenóis/farmacologia , Extratos Vegetais/química , Protetores contra Radiação/farmacologia , Acetona/química , Linhagem Celular , Movimento Celular/efeitos dos fármacos , Movimento Celular/efeitos da radiação , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos da radiação , Ciclo-Oxigenase 2/genética , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Regulação Enzimológica da Expressão Gênica/efeitos da radiação , Queratinócitos/efeitos da radiação , Óxido Nítrico Sintase Tipo II/genética , Fenóis/química , Protetores contra Radiação/química , Pele/citologia , Raios Ultravioleta
17.
Biomacromolecules ; 23(3): 708-719, 2022 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-34968020

RESUMO

The limited utilization of reliable tools and standards for determination of the softwood kraft lignin molar mass and the corresponding molecular conformation hampers elucidation of the structure-property relationships of lignin. At issue, conventional size exclusion chromatography (SEC) is unable to robustly measure the molar mass because of a lack of calibration standards with a similar structure to lignin. In the present work, the determination of the absolute molar mass of acetylated technical lignin was revisited utilizing SEC combined with multi-angle light scattering with a band pass filter to suppress the fluorescence. Fractionated lignin isolated using sequential techniques of solvent and membrane methods was used to enhance the clarity of light-scattering profiles by narrowing the molar mass distribution of lignin fractions. Further information on the molecular conformation of derivatized samples was studied utilizing a differential viscometer, and chemical structures were identified by NMR spectroscopy analysis. Through the help of fractionation, intrinsic viscosity values were determined for the different fractions as a function of molecular weight cut-off membranes. The derivatized acetone-soluble lignin was found to possess a lower molecular weight and an extremely compact structure relative to the derivatized acetone-insoluble fraction based on a significantly lower "α" value in the Mark-Houwink-Sakurada plot (0.15 acetone-soluble vs 0.33 acetone-insoluble). The differences in geometry were supported by the linkage analysis from NMR showing the acetone-soluble part containing fewer native linkages. In both of these examples, kraft lignin behaved like a solid sphere, limiting the ability to provide entanglements between molecular chains. From this standpoint, macroscopic properties of lignin are justified with this knowledge of a dense and extremely compact structure.


Assuntos
Acetona , Lignina , Acetona/química , Lignina/química , Conformação Molecular , Peso Molecular
18.
Environ Sci Pollut Res Int ; 29(13): 19165-19175, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-34709553

RESUMO

The porous structure and oxygen-containing functional groups of carbon materials play important roles in the adsorption of volatile organic compounds (VOCs). In this study, hierarchical-structured porous carbons (HSPCs) with a large specific surface area and abundant oxygen-containing functional groups were prepared from sago cycas without a template or post-processing for acetone (one of the most common VOCs) adsorption. The micropore volume (0.41-1.15 cm3 g-1) and oxygen-containing functional groups (0.3-1.92 mmol g-1) of HSPCs were manipulated by adjusting the activation temperature. Static adsorption data showed that the HSPC activated at 600 °C (HSPC-600) was superior for acetone adsorption, and a maximum adsorption capacity of 3.75 mmol g-1 was achieved at 25 °C and 0.1 kPa. Breakthrough curves and cyclic adsorption-desorption tests demonstrated the dynamic adsorption capacity and regeneration performance of HSPC-600 were excellent as well. The adsorption isotherms were well described by Langmuir and Langmuir-Freundlich models, indicating the adsorption of acetone on HSPCs is a monolayer adsorption process. Due to electrostatic interaction, hydrogen bond and van der Waals forces between acetone molecules and oxygen-containing functional groups, the adsorption capacity of HSPCs for acetone was significantly improved at low relative pressure. This study may provide a peculiar insight into the development of high-performance acetone adsorbent.


Assuntos
Carbono , Cycas , Acetona/química , Adsorção , Carbono/química , Porosidade
19.
Molecules ; 26(23)2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34885752

RESUMO

Considering the toxicity of the impurities of synthesized anthraquinone, this study clarified new catalytic compounds for kraft cooking with improved carbohydrate yield and delignification and less mutagenicity, which are important for ensuring the safety of paper products in contact with food. The 2-methylanthraquinone contents of teak (Tectona grandis) woods were 0.18-0.21%. Acetone extracts containing 2-methylanthraquinone from Myanmar and Indonesia teak woods as additives improved lignin removal during kraft cooking of eucalyptus wood, which resulted in kappa numbers that were 2.2-6.0 points lower than the absence of additive. Myanmar extracts and 2-methylanthraquinone improved carbohydrate yield in pulps with 1.7-2.2% yield gains. Indonesia extracts contained more deoxylapachol and its isomer than 2-methylanthraquinone. The residual content of 2-methylanthraquinone in the kraft pulp was trace. Although Ames tests showed that the Indonesia and Myanmar extracts were mutagenic to Salmonella typhimurium, 2-methylanthraquinone was not. The kraft pulp obtained with the additives should be safe for food-packaging applications, and the addition of 0.03% 2-methylanthraquinone to kraft cooking saves forest resources and fossil energy in industries requiring increased pulp yield.


Assuntos
Carboidratos/biossíntese , Lamiaceae/química , Extratos Vegetais/química , Madeira/química , Acetona/química , Antraquinonas/química , Antraquinonas/toxicidade , Carboidratos/química , Catálise , Eucalyptus/química , Extratos Vegetais/farmacologia
20.
Molecules ; 26(19)2021 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-34641570

RESUMO

Garlic is a health promoter that has important bioactive compounds. The bioactive extraction is an important step in the analysis of constituents present in plant preparations. The purpose of this study is to optimize the extraction with the best proportion of solvents to obtain total phenolic compounds (TPC) and thiosulfinates (TS) from dried garlic powder, and evaluate the antioxidant activities of the optimized extracts. A statistical mixture simplex axial design was used to evaluate the effect of solvents (water, ethanol, and acetone), as well as mixtures of these solvents, after two ultrasound extraction cycles of 15 min. Results showed that solvent mixtures with a high portion of water and pure water were efficient for TPC and TS recovery through this extraction procedure. According to the regression model computed, the most significant solvent mixtures to obtain high TPC and TS recovery from dried garlic powder are, respectively, the binary mixture with 75% water and 25% acetone and pure water. These optimized extracts presented oxygen radical absorbance capacity. Pure water was better for total antioxidant capacity, and the binary mixture of water-acetone (75:25) was better for DPPH scavenging activity. These optimized extracts can be used for industrial and research applications.


Assuntos
Antioxidantes/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Alho/química , Polifenóis/isolamento & purificação , Acetona/química , Antioxidantes/farmacologia , Etanol/química , Compostos Fitoquímicos/isolamento & purificação , Extratos Vegetais/química , Polifenóis/farmacologia , Solventes/química , Água/química
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