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2.
ChemSusChem ; 15(16): e202201006, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-35691934

RESUMO

The synthesis of acetic acid by formal isomerization of methyl formate (MF) was investigated using molecular catalysts. The base-catalyzed decarbonylation of MF, yielding CO and methanol in situ, was integrated with their palladium-catalyzed recombination for the synthesis of acetic acid and methyl acetate in a one pot reaction. The complex [Pd(Cl)2 (dppe)] [dppe=1,2-bis(diphenylphosphino)-ethane] in combination with NaI as iodide source and NaOMe as base were identified as promising molecular components to enable the overall conversion. Sequential application of the statistical methods design of experiments and simplex optimization was used in combination with thermodynamic analysis of the competing reaction pathways for experimental planning and data analysis. Starting from a proof-of-principle with a turnover number (TON) of 11, the catalytic system could thus be optimized to allow quantitative conversion of MF with a TON of 43000, whereby a yield of 83 % of acetate groups and a yield of 74 % for free acetic acid was obtained.


Assuntos
Ácido Acético , Paládio , Catálise , Ésteres do Ácido Fórmico , Isomerismo , Estrutura Molecular
3.
Pest Manag Sci ; 78(7): 3090-3097, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35437899

RESUMO

BACKGROUND: The brown marmorated stink bug (BMSB), Halyomorpha halys, has caused significant agricultural damage to numerous hosts, so agricultural producers seek to limit its spread. Where established, BMSB can also cause substantial urban and commercial disturbance, as overwintering adults may seek refuge inside dwellings, covered spaces, vehicles, and consignments. Phytosanitary authorities are most concerned with the importation of 'hitchhiking' adults in this refugia, with certain countries requiring a quarantine treatment to mitigate risk. This study explores fumigation with ethyl formate, applied as 16.7% by mass dilution in carbon dioxide, for control of adult BMSB. RESULTS: The induction of diapause, to simulate overwintering physiology, resulted in 2- and 3-fold increases in the tolerance of adults toward this ethyl formate fumigation at 10 ± 0.5 °C ( x ¯ ± 2 s ) lasting for 8 and 12 h, respectively. However, a decreased tolerance (0.7-fold) of diapausing specimens was observed for a 4-h duration. Diapausing and nondiapausing adult BMSB can be controlled at the probit 9 level if the headspace concentration of ethyl formate, [EF], in the carbon dioxide mixture is maintained ≥7.68 mg L-1 for 12 h at 10 ± 0.5 °C ( x ¯ ± 2 s ). If the duration is shortened to 4 h, [EF] must be maintained ≥14.73 mg L-1 over the course of fumigation. CONCLUSION: The toxicity of ethyl formate in this mixture can be distinct for different physiological states of the same life stage, as evidenced by a ca. 3-fold increase in the Haber's z parameter for adult BMSB when in diapause. Respective to the physiological state of adults, this study identifies how the applied dose and/or treatment duration can be modulated (i.e. tuned) to ensure adequate toxicological efficacy toward BMSB infesting hosts or refuge at temperatures ca. >10 °C. Published 2022. This article is a U.S. Government work and is in the public domain in the USA.


Assuntos
Dióxido de Carbono , Heterópteros , Animais , Dióxido de Carbono/farmacologia , Di-Hidrotaquisterol , Ésteres do Ácido Fórmico , Fumigação , Heterópteros/fisiologia
4.
Eur J Pharm Sci ; 172: 106157, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35257876

RESUMO

BACKGROUND AND PURPOSE: Despite being a first-line clinical drug, thienopyridines have many unsatisfactory aspects, including the low bioavailability of clopidogrel(CLP) and the high bleeding risk of prasugrel. We synthesized deuterium clopidogrel(D-CL, patented in China) to alleviate the deficiency of CLP in clinical, such as a slow onset, a greater influence of gene polymorphism, and a high frequency of drug-drug interaction. EXPERIMENTAL APPROACH: Molecular docking was used to analyze the affinity between D-CL and the P2Y12 receptor. The levels of active metabolites of D-CL were detected using HPLC/MS-MS and the activities of main metabolic enzymes were analyzed; Subsequently, platelet aggregation function, thrombus model were used to evaluate the pharmacodynamics of D-CL. Finally, the safety of D-CL were evaluated through examination of blood routine, PT, APTT, bleeding time, serological tests, liver pathological biopsy, liver cell apoptosis and detection of apoptosis-related proteins. KEY RESULTS: The introduction of deuterium made the binding of CLP to P2Y12 receptor more stable, improved the concentration of active metabolites, and substantially reduced the inhibition of major metabolic enzymes, including CYP2B6, CYP2C9, and CYP2C19, thereby, exerting better antiplatelet effects without increasing the risk of bleeding, along with a concomitant decrease in the apoptosis of hepatocytes.


Assuntos
Hidrogênio , Inibidores da Agregação Plaquetária , Clopidogrel/farmacologia , Deutério/farmacologia , Ésteres do Ácido Fórmico , Hidrogênio/farmacologia , Simulação de Acoplamento Molecular , Agregação Plaquetária , Inibidores da Agregação Plaquetária/farmacologia , Tiofenos/farmacologia
5.
ChemSusChem ; 15(5): e202102289, 2022 Mar 08.
Artigo em Inglês | MEDLINE | ID: mdl-34979055

RESUMO

The conversion of waste CO2 to value-added chemicals through electrochemical reduction is a promising technology for mitigating climate change while simultaneously providing economic opportunities. The use of non-aqueous solvents like methanol allows for higher CO2 availability and novel products. In this work, the electrochemistry of CO2 reduction in acidic methanol catholyte at a Pb working electrode was investigated while using a separate aqueous anolyte to promote a sustainable water oxidation half-reaction. The selectivity among methyl formate (a product unique to reduction of CO2 in methanol), formic acid, and formate was critically dependent on the catholyte pH, with higher pH conditions leading to formate and low pH favoring methyl formate. The potential dependence of the product distribution in acidic catholyte was also investigated, with a faradaic efficiency for methyl formate as high as 75 % measured at -2.0 V vs. Ag/AgCl.


Assuntos
Dióxido de Carbono , Metanol , Catálise , Técnicas Eletroquímicas , Eletrólitos , Ésteres do Ácido Fórmico , Concentração de Íons de Hidrogênio , Chumbo
6.
J Econ Entomol ; 114(6): 2290-2296, 2021 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-34622933

RESUMO

Ethyl formate (EF) was evaluated as a potential alternative to methyl bromide (MB) for phytosanitary treatment of imported citrus fruit in the Republic of Korea. Planococcus citri (Risso) (Hemiptera: Pseudococcidae), a mealybug with known tolerance against EF and MB, was used as a representative pest to test efficacy of the two fumigants against eggs. In nine commercial-scale refrigerated container (67.5 m3) trials using imported orange, lemon and grapefruit, EF applied at the currently approved dose for citrus (70 g·m-3 at 5°C for 4 h, developed for Aspidiotus excisus Green (Hemiptera: Diaspididae), a species less EF tolerant than P. citri) resulted in 76.9-98.3% mortality of P. citri eggs. The EF treatment did not affect the sugar content or the color of peel and pulp of the treated fruit. When oranges were treated according to the current MB (64 g·m-3 at >5°C for 2 h) or EF treatment guidelines, the concentration of fumigant around the fruit fluctuated between 9.4 and 185.1 ppm for EF and 9.5-203.0 ppm for MB during the 72-h post-fumigation processes (venting [0-2 h], transportation to storage [2-24 h], and storage periods [24-72 h]) with both EF and MB maintained between 10 and 100 ppm during the storage period. Considering the efficacy of EF, its apparent lack of phytotoxicity, and its more manageable threshold limit value for humans (100 ppm EF compared to 1 ppm MB for an 8-h time weighted average exposure), our results suggest that EF may be a promising alternative to MB for the phytosanitary treatment of imported citrus in Korea.


Assuntos
Citrus , Hemípteros , Animais , Ésteres do Ácido Fórmico , Frutas , Fumigação , Hidrocarbonetos Bromados , Local de Trabalho
7.
J Chromatogr A ; 1656: 462547, 2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34551321

RESUMO

Numerous industrial organic pollutants such as aromates, alkoxyalcohols, other organic solvents and monomers are absorbed, metabolized, and finally excreted in urine mostly as carboxylic acids that are determined as biomarkers of exposure. For a number of these xenometabolites, biological limits (levels of biomarkers in biological material) have been established to prevent damage to human health. Till now, most of the analytical procedures used have been optimized for one or a few analytes. Here, we report a more comprehensive approach enabling rapid GC-MS screening of sixteen acidic biomarkers in urine that are metabolized in the human body from several important industrial chemicals; benzene, toluene, styrene, xylenes, alkoxyalcohols, carbon disulfide, furfural and N,N-dimethylformamide. The new method involves immediate in situ derivatization - liquid liquid microextraction of urine by an ethyl chloroformate-ethanol-chloroform-pyridine medium and GC-MS analysis of the derivatized analytes in the lower organic phase. The xenometabolite set represents diverse chemical structures and some of hippuric and mercapturic acids also provided unusual derivatives that were unambiguously elucidated by means of new ethyl chloroformates labeled with stable isotopes and by synthesis of the missing reference standards. In the next step, an automated routine was developed for GC-MS/MS analysis using a MetaboAuto® sample preparation workstation and the new method was validated for fourteen metabolites over the relevant concentration range of each analyte in the spiked pooled human urine. It shows good linearity (R2 ≥ 0.982), accuracy (from 85% to 120%), precision (from 0.7% to 20%) and recovery (from 89% to 120%). The method performance was further successfully proved by GC-MS/MS analysis of the certified IP45 and RM6009 reference urines. Moreover, we show that the new method opens up the possibility for biomonitoring of combined and cumulative occupational exposures as well as for urinary metabolite profiling of persons exposed to harmful industrial chemicals.


Assuntos
Exposição Ocupacional , Espectrometria de Massas em Tandem , Monitoramento Biológico , Biomarcadores , Ésteres do Ácido Fórmico , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Exposição Ocupacional/análise
8.
J Environ Sci Health B ; 56(7): 650-657, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34120567

RESUMO

The use of shipping containers for cargo transportation has the potential to transport insect pests from infested to non-infested areas. Fumigation is required as an appropriate biosecurity measure to exterminate insect pests. Fumigation trials were conducted in a 20 ft general purpose (GP) shipping container. Four species of mixed-age cultures, Lasioderma serricorne (F.), Sitophilus oryzae (L.), Trogoderma variabile (Ballion), and Rhyzopertha dominica (F.) were used for bioassays. Ninety g m-3 of ethyl formate + nitrogen formed non-flammable ethyl formate fumigant formulation was released into the container. The fumigation yielded sufficient concentration × time (Ct) products at a range of 437.54-449.19 g h m-3 in the container for exterminating all life stages. Ethyl formate left no residue in treated drinks. This study demonstrated that on site generation of a non-flammable ethyl formate and nitrogen fumigant can be achieved and this new application technology ensures that ethyl formate distributes evenly in the container within 30 min after application and with a variation of <3%. The research further demonstrated that an ethyl formate + nitrogen application can be used as a pre-shipment treatment for controlling all the stages of insect pests in a shipping container. After a fumigation holding period and ventilation of 15 min, ethyl formate was successfully removed from the container at 0.5-35ppm in different locations. The levels of ethyl formate in the workspace were <0.5 ppm during application, fumigation, and aeriation, which is about 5% of the 100 ppm level for ethyl formate.


Assuntos
Besouros , Inseticidas , Animais , Ésteres do Ácido Fórmico , Fumigação , Nitrogênio
9.
Acta toxicol. argent ; 29(1): 8-10, abr. 2021. graf
Artigo em Espanhol | LILACS | ID: biblio-1360066

RESUMO

Resumen Se describe un caso de quemadura causada por cloroformiato de etilo en ocasión de la respuesta a un incidente que requirió el trasvase del producto desde contenedores defectuosos a otros seguros. La investigación del evento puso en evidenciala necesidad de mantener un protocolo de registro de materiales que ingresan a la zona caliente, que debe ser tenido en cuentaal momento del retiro de los mismos, procediendo a su correcta descontaminación bajo la fiscalización del oficial de seguridad.


Abstract A burn by Ethyl chloroformate in occasion of response to a chemical emergency which required to transfer products from defective containers to safe containers is described. The investigation of the event highlighted the need to maintain aprotocol for the registration of materials to be entered in the hot zone, which must be considered al the moment of remove andproceeding to the proper decontamination under the supervision of the security officer.


Assuntos
Humanos , Masculino , Pessoa de Meia-Idade , Queimaduras Químicas/prevenção & controle , Vazamento de Resíduos Químicos , Ésteres do Ácido Fórmico , Acidentes com Materiais Perigosos , Queimaduras Químicas/diagnóstico , Nádegas , Acidentes de Trabalho/prevenção & controle , Descontaminação , Resíduos Corrosivos
10.
Molecules ; 25(20)2020 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-33050326

RESUMO

Resveratrol (3,5,4'-trihydroxystilbene) is a natural compound that can be found in high concentrations in red wine and in many typical foods found in human diet. Over the past decades, resveratrol has been widely investigated for its potential beneficial effects on human health. At the same time, numerous analytical methods have been developed for the quantitative determination of resveratrol isomers in oenological and food matrices. In the present work, we developed a very fast and sensitive GC-MS method for the determination of resveratrol in red wine based on ethylchloroformate derivatization. Since this reaction occurs directly in the water phase during the extraction process itself, it has the advantage of significantly reducing the overall processing time for the sample. This method presents low limits of quantification (LOQ) (25 ng/mL and 50 ng/mL for cis- and trans-resveratrol, respectively) and excellent accuracy and precision. Ethylchloroformate derivatization was successfully applied to the analysis of resveratrol isomers in a selection of 15 commercial Italian red wines, providing concentration values comparable to those reported in other studies. As this method can be easily extended to other classes of molecules present in red wine, it allows further development of new GC-MS methods for the molecular profiling of oenological matrices.


Assuntos
Ésteres do Ácido Fórmico/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Resveratrol/análise , Resveratrol/química , Vinho/análise , Reprodutibilidade dos Testes
11.
J Environ Sci Health B ; 55(9): 820-826, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32609071

RESUMO

Fumigation is required as an appropriate biosecurity measure to exterminate insect pests in shipping containers. The aim of this study was to determine if ethyl formate (EF) + nitrogen could be safely applied as an in-transit fumigant for containers transported on land and then by sea. In-transit fumigation trials were conducted in four 20 ft shipping containers during a four-day journey in December 2019 in Western Australia. Ethyl formate (90 g m-3) was released with nitrogen into the containers. Ethyl formate concentrations inside the containers and the surrounding environment on the barge were monitored at timed intervals throughout the overnight voyage. This study added new data on in-transit fumigation with ethyl formate + nitrogen via road and has successfully demonstrated safety of in-transit fumigation with ethyl formate + nitrogen via the marine sector. There was no detectable risk to the public, crew members on the barge or workers throughout the journey. In addition, all tested containers were ready to be opened and unloaded with 5-10 minutes aeration or without aeration upon arrival.


Assuntos
Ésteres do Ácido Fórmico/análise , Fumigação/métodos , Nitrogênio/análise , Austrália , Desenho de Equipamento , Navios , Temperatura
12.
Chemosphere ; 258: 127320, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554008

RESUMO

Microorganisms play important roles in the degradation of volatile organic compounds. Aeromonas salmonicida strain (AEP-3) generated from biomass in the citric acid fermentation industry was screened and subjected to denaturing gradient gel electrophoresis (DGGE) fingerprinting and 16S rDNA gene sequencing. The growth conditions of AEP-3 in Luria-Bertani broth were optimized at 25 °C and approximately pH 7. AEP-3 was used to degrade ethyl formate, propionic aldehyde, or acetone alone and their mixture. The concentrations of ethyl formate, propionic aldehyde, and acetone were below 7500, 600, and 800 mg L-1, respectively, and their maximum degradation efficiencies were 100%, 92.41%, and 34.75%. AEP-3 first degraded acetone and propionic aldehyde in the mixture, followed by ethyl formate. The degradation pathways of these organic compounds in the mixture and their substrate interactions during degradation were explored. Propionic aldehyde was first converted into propionic acid in the metabolic process and was involved in the subsequent carboxylic acid cycle. By contrast, ethyl formate was first hydrolyzed into formic acid and ethanol. Then, formic acid participated in the cyclic metabolism of carboxylic acid, whereas, ethanol was hydrolyzed into acetaldehyde and acetic acid through alcohol and aldehyde dehydrogenase. Additionally, acetone directly interacted with nitrate in the medium under the action of hydrogen ions and produced carbon dioxide, water, and nitrogen. Overall, this study provides a new degrading bacterium biodegradability toward the exhaust gas of citric acid fermentation.


Assuntos
Acetona/metabolismo , Aeromonas salmonicida/metabolismo , Ésteres do Ácido Fórmico/metabolismo , Acetaldeído , Ácido Acético/metabolismo , Biodegradação Ambiental , Biomassa , Ácido Cítrico/metabolismo , Etanol/metabolismo , Fermentação , Formiatos , Propionatos/metabolismo
13.
J Econ Entomol ; 113(4): 1711-1717, 2020 08 13.
Artigo em Inglês | MEDLINE | ID: mdl-32372093

RESUMO

Methyl bromide (MB) use for quarantine and phytosanitary purposes is being phased out. Several effective MB alternatives have been identified depending on the target system. Industry commitment for the shift to new technologies will depend not only on the efficacy of alternatives but also on their compatibility and integrability into existing operations. We compared the efficacy of MB and ethyl formate (EF) for disinfestation of Planococcus citri (Risso) (Hemiptera: Pseudococcidae) as a representative surface pest on banana and evaluated whether EF fumigation is compatible with the current packaging materials and loading ratio used by the South Korean banana import industry. Fumigation trials with P. citri adults and eggs showed that EF was at least as effective as MB at the EF and MB concentrations recommended under the current phytosanitary disinfestation guidelines. From a logistical standpoint, EF gas could not effectively penetrate plastic bagging typically used in banana cartons during commercial shipping. Also, EF sorption to bananas and packing materials (used as cushioning inside bagging) further lowered realized EF concentrations around bananas. These reductions in EF concentration translated into reduced mortality of P. citri eggs, indicating that despite similar efficacy of MB and EF for controlling P. citri, further consideration and optimization of other industry logistics such as packaging and loading ratio is necessary to enhance the adoption of this MB alternative.


Assuntos
Musa , Animais , Ésteres do Ácido Fórmico , Fumigação , Hidrocarbonetos Bromados , República da Coreia
14.
Anal Biochem ; 597: 113688, 2020 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-32194075

RESUMO

Glutaric acid is a precursor of a plasticizer that can be used for the production of polyester amides, ester plasticizer, corrosion inhibitor, and others. Glutaric acid can be produced either via bioconversion or chemical synthesis, and some metabolites and intermediates are produced during the reaction. To ensure reaction efficiency, the substrates, intermediates, and products, especially in the bioconversion system, should be closely monitored. Until now, high performance liquid chromatography (HPLC) has generally been used to analyze the glutaric acid-related metabolites, although it demands separate time-consuming derivatization and non-derivatization analyses. To substitute for this unreasonable analytical method, we applied herein a gas chromatography - mass spectrometry (GC-MS) method with ethyl chloroformate (ECF) derivatization to simultaneously monitor the major metabolites. We determined the suitability of GC-MS analysis using defined concentrations of six metabolites (l-lysine, cadaverine, 5-aminovaleric acid, 2-oxoglutaric acid, glutamate, and glutaric acid) and their mass chromatograms, regression equations, regression coefficient values (R2), dynamic ranges (mM), and retention times (RT). This method successfully monitored the production process in complex fermentation broth.


Assuntos
Ésteres do Ácido Fórmico/metabolismo , Glutaratos/metabolismo , Lisina/metabolismo , Cromatografia Líquida de Alta Pressão , Fermentação , Ésteres do Ácido Fórmico/química , Cromatografia Gasosa-Espectrometria de Massas , Glutaratos/química , Lisina/química , Estrutura Molecular
15.
Molecules ; 25(4)2020 Feb 21.
Artigo em Inglês | MEDLINE | ID: mdl-32098283

RESUMO

Periodic Mesoporous Organosilica Nanoparticles (PMONPs) are nanoparticles of high interest for nanomedicine applications. These nanoparticles are not composed of silica (SiO2). They belong to hybrid organic-inorganic systems. We considered using these nanoparticles for CO2 release as a contrast agent for High Intensity Focused Ultrasounds (HIFU). Three molecules (P1-P3) possessing two to four triethoxysilyl groups were synthesized through click chemistry. These molecules possess a tert-butoxycarbonyl (BOC) group whose cleavage in water at 90-100 °C releases CO2. Bis(triethoxysilyl)ethylene E was mixed with the molecules Pn (or not for P3) at a proportion of 90/10 to 75/25, and the polymerization triggered by the sol-gel procedure led to PMONPs. PMONPs were characterized by different techniques, and nanorods of 200-300 nm were obtained. These nanorods were porous at a proportion of 90/10, but non-porous at 75/25. Alternatively, molecules P3 alone led to mesoporous nanoparticles of 100 nm diameter. The BOC group was stable, but it was cleaved at pH 1 in boiling water. Molecules possessing a BOC group were successfully used for the preparation of nanoparticles for CO2 release. The BOC group was stable and we did not observe release of CO2 under HIFU at lysosomal pH of 5.5. The pH needed to be adjusted to 1 in boiling water to cleave the BOC group. Nevertheless, the concept is interesting for HIFU theranostic agents.


Assuntos
Nanomedicina , Nanopartículas/química , Compostos de Organossilício/química , Dióxido de Silício/química , Dióxido de Carbono/química , Química Click , Meios de Contraste/química , Portadores de Fármacos/química , Ésteres do Ácido Fórmico/química , Humanos , Nanopartículas/uso terapêutico , Nanotubos/química , Compostos de Organossilício/uso terapêutico , Porosidade , Dióxido de Silício/uso terapêutico
16.
Biomolecules ; 10(1)2020 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-31906270

RESUMO

Current methods for the production of esters, including chemical synthesis and extraction from natural sources, are hindered by low yields and environmental pollution. The enzymatic synthesis of these compounds could help overcome these problems. In this study, phenethyl formate, a commercially valuable formate ester, was synthesized using commercial immobilized lipases. The effects of specific enzymes, enzyme concentration, formic acid:phenethyl alcohol molar ratio, temperature, and solvent were studied in order to optimize the synthesis conditions, which were identified as 15 g/L of Novozym 435 enzyme, a 1:5 formic acid:phenethyl alcohol molar ratio, a 40 °C reaction temperature, and 1,2-dichloroethane as the solvent. Under these conditions, phenethyl formate was obtained in a conversion yield of 95.92%. In addition, when 1,2-dichloroethane was replaced with toluene as the solvent, the enzyme could be recycled for at least 20 reactions with a steady conversion yield above 92%, testifying to the economic aspects of the process. The enzymatic synthesis of phenethyl formate using the proposed method is more environmentally friendly than methods currently employed in academic and laboratory settings. Moreover, the method has the potential to enhance the value-added properties of formic acid owing to its downstream use in the production of commercially essential esters.


Assuntos
Formiatos/química , Ésteres do Ácido Fórmico/química , Ésteres do Ácido Fórmico/síntese química , Biocatálise , Enzimas Imobilizadas/química , Esterificação , Ésteres/química , Álcool Feniletílico/química , Solventes , Temperatura
17.
J Sep Sci ; 43(6): 1100-1106, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31858708

RESUMO

A green and fast analytical method for the determination of l-methionine in human plasma is presented in this study. Preconcentration of the analyte was carried out by switchable solvent liquid phase microextraction after ethyl chloroformate derivatization reaction. Instrumental detection of the analyte was performed by means of gas chromatography-mass spectrometry. N,N-Dimethyl benzylamine was used in the synthesis of switchable solvent. Protonated N,N-dimethyl benzylamine volume, volume/concentration of sodium hydroxide, and vortex period were meticulously fixed to their optimum values. Besides, ethyl chloroformate, pyridine, and ethanol volumes were optimized in order to get high derivatization yield. After the optimization studies, limit of detection and quantitation values were attained as 3.30 and 11.0 ng/g, respectively, by the developed switchable solvent liquid phase microextraction gas chromatography-mass spectrometry method that corresponding to 76.7-folds enhancement in detection power of the gas chromatography-mass spectrometry system. Applicability and accuracy of the switchable solvent liquid phase microextraction-gas chromatography-mass spectrometry method were also checked by spiking experiments. Percent recovery results were ranged from 97.8 to 100.5% showing that human plasma samples could be analyzed for its l-methionine level by the proposed method.


Assuntos
Aminas/química , Ésteres do Ácido Fórmico/química , Microextração em Fase Líquida , Metionina/sangue , Ondas Ultrassônicas , Aminas/síntese química , Cromatografia Gasosa-Espectrometria de Massas , Voluntários Saudáveis , Humanos , Estrutura Molecular , Solventes/química
18.
J Agric Food Chem ; 67(50): 13914-13921, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31757122

RESUMO

Ethyl formate (EF) is a generally recognized-as-safe flavoring agent commonly used in the food industry. It is a naturally occurring volatile with insecticidal and antimicrobial properties, promising as an alternate fumigant to methyl bromide which is undesirable due to its ozone depletion in the stratosphere and toxic properties. However, EF is highly volatile, flammable, and susceptible to hydrolytic degradation. These properties present considerable end-use challenges. In this study, a precursor of EF was synthesized via the condensation reaction of adipic acid dihydrazide and triethyl orthoformate to form diethyl N,N'-adipoyldiformohydrazonate, as confirmed by Fourier transformed infrared and solid-state nuclear magnetic resonance spectroscopies. Differential scanning calorimetry analysis showed that the precursor had a melting point of 174 °C. The physical properties of the precursor were studied using scanning electron microscopy and dynamic light scattering analysis, which showed that the precursor was made up of agglomerated particulates with irregular shapes and sizes. The resulting precursor was nonvolatile and remained stable under dry conditions but could be hydrolyzed readily to trigger the release of EF. The release behaviors of EF from the precursor was evaluated by citric acid-catalyzed hydrolysis, showing that 0.38 ± 0.008 mg EF/mg precursor was released after 2 h at 25 °C, representing about 98% of the theoretical loading. Both EF release rate and its total release amount decreased significantly (p < 0.05) with decreasing temperature and relative humidity. The conversion of the highly volatile EF into a solid-state precursor, in conjunction with the activated release strategy, can be useful for controlled release of EF for fumigation and other applications in destroying insect pests and inhibiting the proliferation of spoilage microorganisms.


Assuntos
Preparações de Ação Retardada/química , Preparações de Ação Retardada/síntese química , Ésteres do Ácido Fórmico/química , Inseticidas/síntese química , Animais , Preparações de Ação Retardada/farmacologia , Ésteres do Ácido Fórmico/farmacologia , Fumigação , Controle de Insetos , Insetos/efeitos dos fármacos , Inseticidas/química , Inseticidas/farmacologia
19.
Sci Rep ; 9(1): 14605, 2019 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-31601880

RESUMO

Infestation of phosphine (PH3) resistant insects threatens global grain reserves. PH3 fumigation controls rice weevil (Sitophilus oryzae) but not highly resistant insect pests. Here, we investigated naturally occurring strains of S. oryzae that were moderately resistant (MR), strongly resistant (SR), or susceptible (wild-type; WT) to PH3 using global proteome analysis and mitochondrial DNA sequencing. Both PH3 resistant (PH3-R) strains exhibited higher susceptibility to ethyl formate-mediated inhibition of cytochrome c oxidase than the WT strain, whereas the disinfectant PH3 concentration time of the SR strain was much longer than that of the MR strain. Unlike the MR strain, which showed altered expression levels of genes encoding metabolic enzymes involved in catabolic pathways that minimize metabolic burden, the SR strain showed changes in the mitochondrial respiratory chain. Our results suggest that the acquisition of strong PH3 resistance necessitates the avoidance of oxidative phosphorylation through the accumulation of a few non-synonymous mutations in mitochondrial genes encoding complex I subunits as well as nuclear genes encoding dihydrolipoamide dehydrogenase, concomitant with metabolic reprogramming, a recognized hallmark of cancer metabolism. Taken together, our data suggest that reprogrammed metabolism represents a survival strategy of SR insect pests for the compensation of minimized energy transduction under anoxic conditions. Therefore, understanding the resistance mechanism of PH3-R strains will support the development of new strategies to control insect pests.


Assuntos
Complexo IV da Cadeia de Transporte de Elétrons/metabolismo , Resistência a Inseticidas , Inseticidas , Fosfinas , Gorgulhos/genética , Animais , DNA Mitocondrial/genética , Complexo IV da Cadeia de Transporte de Elétrons/antagonistas & inibidores , Metabolismo Energético , Ésteres do Ácido Fórmico , Mitocôndrias/metabolismo , Mutação , Oxirredução , Polimorfismo de Nucleotídeo Único , Proteoma , Proteômica , Análise de Regressão , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Gorgulhos/enzimologia
20.
Environ Sci Pollut Res Int ; 26(31): 32209-32223, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31494857

RESUMO

CO2 and H2S removal from flue gases is indispensable to be done for protection of environment with respect to global warming as well as clean air. Chemical absorption is one of the most developed and capable techniques for the removal of these sour gases. Among the many solvents, ionic liquids (ILs) are more capable due to their desirable green solvent properties. However, ILs being usually costlier, the blends of ILs and amines are more suggestive for absorption. In the present work, various essential characterization properties such as density, viscosity, sound velocity, and refractive index of two ionic liquid-amine blend systems viz. (1) 2-Hydroxy ethyl ammonium formate (HEF) + 1-(2-aminoethyl) piperazine (AEP) and (2) 2-Hydroxy ethyl ammonium formate (HEF) + 2-Amino-2-methyl-1-propanol (AMP) are reported. The temperature range for which all the measurements were conducted is 298.15 to 333.15 K. For both systems of (HEF + AEP) and (HEF + AMP), HEF mass fractions were varied from 0.2 to 0.8.The density and viscosity results were correlated as a function of temperature and concentration of ionic liquid and amine with Redlich-Kister and Grunberg-Nissan models, respectively. Moreover, feed forward neural network model (ANN) is explored for correlating experimentally determined sound velocity and refractive index data. The measured properties are further analyzed to estimate various thermodynamic as well as transport properties such as diffusivity of CO2/H2S in the (HEF + AEP) and (HEF + AMP), thermal expansion coefficients, and isentropic compressibility, ΔG0, ΔS0, ΔH0, using the available models in the literature.


Assuntos
Monofosfato de Adenosina/análise , Compostos de Amônio/química , Dióxido de Carbono/química , Líquidos Iônicos/química , Íons/química , Acústica , Monofosfato de Adenosina/química , Aminas , Ésteres do Ácido Fórmico/química , Temperatura Alta , Reologia , Solventes/química , Temperatura , Termodinâmica , Viscosidade
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