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1.
Food Chem ; 334: 127563, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32791433

RESUMO

A new magnetic Cu(II) IIP (Fe3O4@IIP-IDC) is synthesized by polymerization of Imidazole-4,5-dicarboxylic acid functionalized Allyl chloride, and significant improvement of its performance has been compared. SPE parameters were optimized using Box-Behnken design to achieve the twin objectives of quantitative determination and removal of Cu(II). FLPSO kinetic model and BS isotherm model fits well with the capacity of 175 mg g-1. Analytical figures of merit includes a linearity range of 10-5,000 µg L-1 (R2 = 0.9986), preconcentration factor of 50 after eluting with 5 mL of 1 M HNO3, LOD of 1.03 µg L-1 and LOQ of 4.5 µg L-1. Accuracy was assessed by analysis of SRM (Standard Reference Material) and recovery experiments after spiking in food samples (Tea, coffee, chocolate, spinach, infant milk substitute) and battery wastewater. Ease of use, reusability (15 cycles), rapid adsorption and high selectivity makes it a promising candidate for efficient and selective removal and trace determination.


Assuntos
Cobre/análise , Análise de Alimentos/métodos , Impressão Molecular/métodos , Polímeros/química , Poluentes Químicos da Água/análise , Adsorção , Compostos Alílicos/química , Cobre/isolamento & purificação , Ácidos Dicarboxílicos/química , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Imidazóis/química , Limite de Detecção , Fenômenos Magnéticos , Águas Residuárias/análise , Poluentes Químicos da Água/isolamento & purificação
2.
Food Chem ; 334: 127345, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32712485

RESUMO

The development of a novel molecularly imprinted solid-phase extraction (MISPE) method for simultaneous preconcentration of imazapyr (IMP), imazapic (IMZ) and imazethapyr (IMT) with determination by HPLC-PAD (High performance liquid chromatography - photodiode-array detector) is proposed. The polymer synthesis was performed using imazethapyr as template molecule and 1-vinylimidazole as functional monomer. The method is based on preconcentration of 100.0 mL of sample through 200.0 mg of molecularly imprinted poly(vinylimidazole-TRIM) (MIP-1VN) at pH 4.0, followed by elution with 2.0 mL of MeOH:CH2Cl2:HAc (34:62:4, v/v). The range of analytical curve (0.29-200.0, 0.21-200.0 and 0.15-200.0 µg L-1), limits of detection (0.09, 0.06 and 0.04 µg L-1) and preconcentration factors (92, 96 and 98) determined for the herbicides, IMP, IMZ and IMT, respectively, were greatly superior when compared with those ones obtained with commercial adsorbents. The analytical method was successfully applied to spiked surface water and rice samples with good results of recovery values (86-107%).


Assuntos
Herbicidas/análise , Impressão Molecular/métodos , Oryza/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Alimentos/análise , Imidazóis/análise , Imidazóis/síntese química , Imidazóis/química , Limite de Detecção , Niacina/análogos & derivados , Niacina/análise , Ácidos Nicotínicos/análise , Ácidos Nicotínicos/química , Polivinil/síntese química , Polivinil/química , Sementes/química , Extração em Fase Sólida/instrumentação
3.
Anticancer Res ; 40(9): 5081-5090, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32878796

RESUMO

BACKGROUND/AIM: Triple negative breast cancer (TNBC) is an aggressive type of breast cancer with limited targets for chemotherapy. This study evaluated the inhibitory effects of novel imidazo[2,1-b]oxazole-based rapidly accelerated fibrosarcoma (RAF) inhibitors, KIST0215-1 and KIST0215-2, on epithelial cell transformation and TNBC tumorigenesis. MATERIALS AND METHODS: Immunoblotting, BrdU incorporation assay, reporter gene assay, and soft agar assay analyses were performed. In vivo effects were studied using the BALB/c mouse xenograft model. RESULTS: KIST0215-1 and KIST0215-2 inhibited the RAFs-MEK1/2-ERK1/2 signalling pathway induced by EGF in MDA-MB-231 cells, which inhibited c-fos transcriptional activity and activator protein-1 transactivation activity. KIST0215-1 and KIST0215-2 also prevented neoplastic transformation of JB6 C141 mouse epidermal cells induced by EGF and consistently suppressed the growth of tumours formed by 4T1 cells in BALB/c mice. CONCLUSION: Inhibition of RAF kinases using KIST0215-1 and KIST0215-2 is a promising chemotherapeutic strategy to treat TNBC.


Assuntos
Antineoplásicos/farmacologia , Transformação Celular Neoplásica/efeitos dos fármacos , Transição Epitelial-Mesenquimal/efeitos dos fármacos , Imidazóis/farmacologia , Neoplasias de Mama Triplo Negativas/etiologia , Neoplasias de Mama Triplo Negativas/metabolismo , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Transformação Celular Neoplásica/metabolismo , Modelos Animais de Doenças , Transição Epitelial-Mesenquimal/genética , Feminino , Genes Reporter , Humanos , Imidazóis/química , Camundongos , Estrutura Molecular , Transdução de Sinais/efeitos dos fármacos , Neoplasias de Mama Triplo Negativas/patologia , Ensaios Antitumorais Modelo de Xenoenxerto
4.
Chemosphere ; 254: 126918, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32957302

RESUMO

The increasing application of various surfactants nowadays, may lead to the contamination of the natural environment and represent potential threat to terrestrial higher plants. In this article, the effect of 13 surfactants, with dodecyl alkyl chain and various aromatic (imidazolium, pyridinium, thiazolium) and aliphatic (guanidinium, ammonium, thiosemicarbazidium) polar heads, on germination, development and growth of wheat and cucumber was investigated. The study aimed to prove how changes in lipophilicity of surfactants and their various structural modifications (existence of the aliphatic or aromatic polar group, the introduction of oxygen and sulfur) influence toxicity towards investigated plants. The calculated lipophilic parameter (AlogP) is shown to be a useful parameter for predicting potential toxicity of the compound. The strategy of using surfactants with aliphatic polar heads instead of aromatic prove to be a promising strategy in reducing harmful effect, as well as the introduction of polar groups in the structure of cation. From all investigated compounds, surfactants with imidazolium polar head displayed the most harmful effect towards wheat and cucumber. The cucumber seeds were more sensitive to the addition of surfactants comparing to wheat. All obtained experimental results were additionally investigated using computational methods, simulating the transport of surfactants through a lipid bilayer. The influence of cation tendency to fit in lipid bilayer structure was correlated with toxicity. For the first time, it is concluded that cation ability to mimic the structure of bilayer have less harmful effect on plant development.


Assuntos
Cucumis sativus/efeitos dos fármacos , Imidazóis/toxicidade , Compostos de Piridínio/toxicidade , Tensoativos/toxicidade , Triticum/efeitos dos fármacos , Cátions , Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Cucumis sativus/crescimento & desenvolvimento , Germinação/efeitos dos fármacos , Imidazóis/química , Bicamadas Lipídicas/química , Simulação de Dinâmica Molecular , Compostos de Piridínio/química , Compostos de Piridínio/farmacologia , Plântula/efeitos dos fármacos , Plântula/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Sementes/crescimento & desenvolvimento , Relação Estrutura-Atividade , Tensoativos/química , Triticum/crescimento & desenvolvimento
5.
Anticancer Res ; 40(9): 4913-4919, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32878779

RESUMO

BACKGROUND/AIM: A new class of imidazo[2,1-b][1,3,4]thiadiazole compounds have recently been evaluated as inhibitors of phosphorylation of focal adhesion kinase (FAK) in pancreatic cancer. FAK is overexpressed in mesothelioma and has recently emerged as an interesting target for the treatment of this disease. MATERIALS AND METHODS: Ten imidazo[2,1-b][1,3,4]thiadiazole compounds characterized by indole bicycle and a thiophene ring, were evaluated for their cytotoxic activity in two primary cell cultures of peritoneal mesothelioma, MesoII and STO cells. RESULTS: Compounds 1a and 1b showed promising antitumor activity with IC50 values in the range of 0.59 to 2.81 µM in both cell lines growing as monolayers or as spheroids. Their antiproliferative and antimigratory activity was associated with inhibition of phospho-FAK, as detected by a specific ELISA assay in STO cells. Interestingly, these compounds potentiated the antiproliferative activity of gemcitabine, and these results might be explained by the increase in the mRNA expression of the key gemcitabine transporter human equilibrative nucleoside transporter-1 (hENT-1). CONCLUSION: These promising results support further studies on new imidazo[2,1-b][1,3,4]thiadiazole compounds as well as on the role of both FAK and hENT-1 modulation in order to develop new drug combinations for peritoneal mesothelioma.


Assuntos
Antineoplásicos/farmacologia , Desoxicitidina/análogos & derivados , Transportador Equilibrativo 1 de Nucleosídeo/genética , Quinase 1 de Adesão Focal/metabolismo , Imidazóis/farmacologia , Tiadiazóis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Desoxicitidina/farmacologia , Sinergismo Farmacológico , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Imidazóis/síntese química , Imidazóis/química , Mesotelioma/tratamento farmacológico , Mesotelioma/patologia , Estrutura Molecular , Neoplasias Peritoneais/tratamento farmacológico , Neoplasias Peritoneais/patologia , Fosforilação/efeitos dos fármacos , Tiadiazóis/síntese química , Tiadiazóis/química , Células Tumorais Cultivadas
6.
SAR QSAR Environ Res ; 31(10): 761-784, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32867537

RESUMO

The free COOH group of conventional NSAIDs is a structural feature for non-selective cyclooxygenase (COX) inhibition and the molecular cause of their gastrointestinal (GI) toxicity. In this context, an in house database of synthesizable ester prodrugs of some well-known NSAIDs was developed by combining their -COOH group with -OH of a newly identified antioxidant 4-(1H-benzo[d]imidazol-2-yl)phenol (BZ). The antioxidant potential of BZ was unveiled through in silico PASS prediction and in vitro/in vivo evaluation. The in house database of NSAIDs-BZ prodrugs was first subjected to screening with our previously reported pharmacophore models of hCES1 (AAHRR.430) and hCES2 (AHHR.21) for determining hydrolytic susceptibility. Biotransformation behaviour of screened prodrugs was then assessed by using QM/MM and sterimol parameterization, followed by ADMET calculations to predict the drug likeness. On the basis of in silico results, five prodrugs were duly synthesized and the best three were subject to the in vivo evaluation for their anti-inflammatory, analgesic, antioxidant activities, and ulcerogenic index. Among these prodrugs, BN2 and BN5 displayed better anti-inflammatory and analgesics potential in comparison to their parent drugs. All the prodrugs were found to be gastro sparing in the rat model and significantly improved the levels of oxidative stress biomarkers in both blood plasma as well as gastric homogenate.


Assuntos
Anti-Inflamatórios não Esteroides/síntese química , Imidazóis/química , Fenóis/química , Pró-Fármacos/síntese química , Relação Quantitativa Estrutura-Atividade , Simulação por Computador
7.
J Chromatogr A ; 1628: 461448, 2020 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-32822987

RESUMO

During a screening of cyclodextrins (CDs) as chiral selectors for the separation of daclatasvir (DCV) and its enantiomer by capillary electrophoresis (CE), an unusual phenomenon for CDs was observed, that is two peaks with a plateau in between using γ-CD as chiral selector. The same result was encountered when enantiopure DCV was injected or when analyzing a sample containing enantiopure DCV and γ-CD in a CD-free background electrolyte. Peak coalescence was observed at 45°C and at a pH above 3.5. Two peaks with a plateau were also observed for DCV stereoisomers as well as a structural analog. However, only a single peak was detected if one or both amino acid moieties of DCV were lacking. Nuclear magnetic resonance (NMR) experiments including Nuclear Overhauser effect-based methods showed that in solution DCV adopted a folded conformation in which the isopropyl side chain of the valine residues pointed toward the aromatic rings of DCV. Moreover, NMR unequivocally demonstrated the simultaneous formation of DCV-γ-CD inclusion complexes with 1:1 and 2:1 stoichiometry, which was corroborated by mass spectrometry. In both complexes, DCV also adopted a folded structure. The RSSR-diastereomer of DCV as well as an analog lacking one of the amino acid moieties also formed 1:1 and 2:1 complexes with γ-CD although a plateau was only observed in the case of the RSSR-diastereomer. As shown by CE-MS, both DCV-γ-CD complexes surprisingly comigrated as the first peak, while the second migrating peak represents non-complexed DCV.


Assuntos
Imidazóis/química , gama-Ciclodextrinas/química , Eletroforese Capilar , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Conformação Molecular , Estereoisomerismo
8.
Free Radic Res ; 54(7): 517-524, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32781874

RESUMO

The present study reports radiation-chemical yields of 2.5-diaminoimidazolone (Iz) derivatives in X-irradiated phosphate-buffered solutions of guanosine and double-stranded DNA. Various gassing conditions (air, N20/O2 (4:1), N2O, vacuum) were employed to elucidate the contribution of several alternative pathways leading to Iz in reactions initiated by hydroxyl radical attack on guanine. In all systems, Iz was identified as the second by abundance guanine degradation product after 8-oxoguanine, formed in 1:5 (guanosine) and 1:3.3 (DNA) ratio to the latter in air-saturated solutions. Experimental data strongly suggest that the addition of molecular oxygen to the neutral guanine radical G(-H)• plays a major in Iz production in oxygenated solutions of double-stranded DNA while in other systems it may compete with recombination of G(-H)• with superoxide and/or alkyl peroxyl radicals. The production of Iz through hydroxyl radical attack on 8-oxoguanine was also shown to take place although the chemical yield of Iz (ca 6%) in this process is too low to compete with the other pathways. The linearity of Iz accumulation with dose also indicates a negligible contribution of this channel to its yield in all systems.


Assuntos
Dano ao DNA , DNA/química , Radicais Livres/química , Radical Hidroxila/química , Imidazóis/química , 8-Hidroxi-2'-Desoxiguanosina/química , Animais , DNA/efeitos da radiação , Diaminas/química , Guanosina/química , Masculino , Salmão
9.
Ecotoxicol Environ Saf ; 205: 111110, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32810646

RESUMO

ZIF-8 nanoparticles (NPs) has been demonstrated with good potential in drug delivery, which causes an increasing attention on relevant toxicity study. In this work, MTT (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide), glutathione (GSH), reactive oxygen species (ROS), stain analysis and gene detection assays were performed on ZIF-8 (50, 90 and 200 nm) incubated HepG2 cells. Moreover, time-resolved inductively coupled plasma mass spectrometry (TRA-ICP-MS) was applied for single cell analysis; the variation in cellular zinc amount and the proportion of zinc up-taken cells was investigated as a function of NPs size, incubation concentration/time and elimination. Smaller size of ZIF-8 NPs would lead to higher zinc accumulation and toxicity. The function of ZIF-8 on cells is assumed to be mainly related to zinc intracellular accumulation. The possible action path is presented as high accumulation of zinc in ZIF-8 incubated cells lead to high ROS level and cellular inflammation, ultimately inducing necrocytosis. For better understanding of the bio-effect of ZIF-8, ZnO NPs and Zn2+ incubated HepG2 cells were evaluated in the same way. Higher accumulation of zinc in larger part of the cell population was found in ZIF-8 incubated cells than that in ZnO NPs incubated cells. It demonstrated higher bioavailability for ZIF-8 over ZnO NPs. While, in drug delivery application, the possible risk of the remained intracellular ZIF-8 cannot be ignored.


Assuntos
Imidazóis/química , Estruturas Metalorgânicas/toxicidade , Nanopartículas/toxicidade , Óxido de Zinco/toxicidade , Zinco/química , Bioensaio , Disponibilidade Biológica , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Glutationa/farmacologia , Células Hep G2 , Humanos , Estruturas Metalorgânicas/química , Estruturas Metalorgânicas/metabolismo , Nanopartículas/química , Tamanho da Partícula , Espécies Reativas de Oxigênio/metabolismo , Análise de Célula Única , Óxido de Zinco/química
10.
Ecotoxicol Environ Saf ; 205: 111187, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32853869

RESUMO

Ionic liquids have been becoming new 'green solvent' because of the low saturation vapor pressure, less volatilization and more recycling utilization. Since most ILs are soluble in water, it should be indispensable to evaluate the ecotoxicology effect of ILs on aquatic environment before using them widely. Based on the concept of norm index, a set of norm descriptors were proposed for anions, cations and ILs. The whole IL structure optimization method has been used to build a predictive norm index-based quantitative structure-toxicity relationship model for the toxicity of ILs on Vibrio fischeri. Statistical results indicated that norm descriptors were reliable and robust in expressing the relationship between structural information and toxicity of ILs. Meanwhile, a series of ILs without experimental values were predicted based on this stable QSTR model. The results indicated that for imidazole-based ILs, an increase in the length of substituent in the branch could enhance the toxicity of ILs on Vibrio fischeri, and the branch contains hydroxyl group, double bond or triple bonds might reduce the toxicity of ILs. Results obtained in this present work would be valuable for the molecular design and the toxicity evaluation toward aquatic organism of ILs.


Assuntos
Aliivibrio fischeri/efeitos dos fármacos , Imidazóis , Líquidos Iônicos , Modelos Teóricos , Solventes , Ânions/química , Cátions/química , Ecotoxicologia/métodos , Imidazóis/química , Imidazóis/toxicidade , Líquidos Iônicos/química , Líquidos Iônicos/toxicidade , Valor Preditivo dos Testes , Relação Quantitativa Estrutura-Atividade , Solventes/química , Solventes/toxicidade
11.
J Chromatogr A ; 1626: 461358, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797837

RESUMO

In this study, the in-situ conversion of the synthesized Co-Al layered double hydroxide (Co-Al LDH) nanosheets to three dimensional hierarchical zeolitic imidazolate framework-67 (3D HZIF-67) was presented as a cost-effective, highly efficient, flexible and robust sorbent to carry out the microextraction process. In the first stage, the anodized aluminum foil was prepared electrochemically. Then, the Co-Al LDH precursor was constructed on the surface of the previously-prepared anodized Al foil applying in-situ formation approach. The procedure is followed by the conversion of the prepared Co-Al LDH film to 3D HZIF-67 film via a facile solvothermal method without adding cobalt salt. The in-situ prepared 3D HZIF-67-anodized Al was used for the thin film microextraction (TFME) of caffeine. The effective factors in TFME procedure were investigated and optimized through applying Central Composite Design (CCD). In the obtained optimal condition, the calibration curves for TFME-HPLC-UV of caffeine were linear in the range of 1-200 µg L-1 with the coefficient of determination (r2) higher than 0.9915. The limits of detection were 0.33 and 0.38 µg L-1, in water and urine matrices, respectively. Moreover, the enrichment factors (EFs) and absolute recoveries (%AR) were also calculated as 173-198 and 57.1%-65.3%, respectively. The inter-day relative standard deviations (RSDs) were evaluated as the method precision for 20 and 200 µg L-1 of spiked sample and were between 4.9-6.1%. The repeatability of the preparation step was investigated as batch-to-batch reproducibility and it was found to be 4.9%; as a result, the reproducibility of the presented film was approved. Finally, the proposed method was utilized to determine caffeine (as the model analyte) from different types of real samples including urine, coffee, beverage (Pepsi) and shampoo. The obtained recoveries (higher than 88%) confirmed the capability of the method for real sample analysis.


Assuntos
Alumínio/química , Cafeína/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Cobalto/química , Hidróxidos/química , Imidazóis/química , Raios Ultravioleta , Zeolitas/química , Adsorção , Eletrodos , Limite de Detecção , Microscopia de Força Atômica , Porosidade , Reprodutibilidade dos Testes , Solventes/química , Propriedades de Superfície
12.
J Oleo Sci ; 69(7): 743-750, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32612024

RESUMO

In this study, two new mixed-ligand coordination polymers {[Co(bbi)(tdc)]·5H2O}n (1, bbi = 1,4-bis(imidazolyl)butane) and {[Cu2(bimb)(H2O)(µ3-tdc)2(DMF)2]·H2O}n (2, bimb = 4-bis(1H-imidazol-1-yl-methyl)benzene) were synthesized under the solvothermal conditions via reaction of 2,5-thiophenedicarboxylic acid (H2tdc) with the corresponding metal salts in the existence of different flexible bis-imidazole ligands (bbi for 1 and bimb for 2). The as-prepared two structures were detected via the single crystal X-ray diffraction (SXRD) and then characterized via the analysis of element, powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA) as well as infrared (IR) spectroscopy. Furthermore, the protective activity of the compound on the mice with ischemic stroke was evaluated. Firstly, the real time reverse transcription-polymerase chain raction (RT-PCR) was carried out to determine the effect of compounds 1 and 2 against the relative expression level of the glucagon-like peptide 1 receptors (glp1r) on the cerebrovascular endothelial cells. Next, the Morris Water Maze Experiment was also used to detect the improvement function of compounds 1 and 2 on the nice mice cognitive function.


Assuntos
Encéfalo/metabolismo , Complexos de Coordenação/síntese química , Complexos de Coordenação/farmacologia , Expressão Gênica/efeitos dos fármacos , Receptor do Peptídeo Semelhante ao Glucagon 1/genética , Receptor do Peptídeo Semelhante ao Glucagon 1/metabolismo , Metais/química , Polímeros/síntese química , Acidente Vascular Cerebral/tratamento farmacológico , Acidente Vascular Cerebral/genética , Tiofenos/química , Animais , Encéfalo/citologia , Fenômenos Químicos , Cognição/efeitos dos fármacos , Complexos de Coordenação/uso terapêutico , Cristalização , Células Endoteliais/metabolismo , Imidazóis/química , Ligantes , Aprendizagem em Labirinto/efeitos dos fármacos , Camundongos , Modelos Moleculares , Conformação Molecular , Polímeros/química , Relação Estrutura-Atividade , Difração de Raios X
13.
J Chromatogr A ; 1625: 461284, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709334

RESUMO

In this work, a class of novel and eco-friendly open-tubular (OT) chiral column was presented for the first time by one step preparation with zeolite imidazolate framework-8 (ZIF-8) and bovine serum album (BSA) based on electrostatic adsorption and adsorption affinity. This stationary phase materials combined the features of large surface areas and adsorption affinity of ZIF-8, and also the multiple chiral binding sites of BSA, which contributes to the π-interaction and hydrophobic interaction with the analytes. The separation performance of BSA@ZIF-8-OT chiral columns was evaluated with a miniaturized capillary electrochromatography and amperometric detection (mini-CEC-AD) system; in particular, nine groups of model molecules, including homologues, structural isomers, and chiral compounds, were baseline separated under the certain optimum conditions. The RSDs of run-to-run, day-to-day, column-to-column, and batch-to-batch reproducibility were less than 13.8 %. Furthermore, the prepared OT columns were successfully applied to fast analysis of ephedrine isomers in Chinese herb ephedra, and the LODs achieved 1.5-2.0 ng mL-1 (S/N=3) by an electrophoretic stacking technique of moving chemical reaction boundary. This mini-CEC-AD system with BSA@ZIF-8-OT chiral columns provides a promising potential in pharmaceutical analysis due to its fast, sensitive, enantioselective, and low-cost characteristics.


Assuntos
Eletrocromatografia Capilar/métodos , Imidazóis/química , Soroalbumina Bovina/química , Zeolitas/química , Adsorção , Animais , Bovinos , Concentração de Íons de Hidrogênio , Limite de Detecção , Reprodutibilidade dos Testes , Estereoisomerismo
14.
Food Chem ; 333: 127499, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32673957

RESUMO

This study was to examine the formation of advanced glycation end-products (AGEs) in black tea during drying process at 90, 120, and 150 °C for 1 h. Nine AGEs including Nɛ-(carboxyethyl)-l-lysine (CEL), Nɛ-(carboxymethyl)-l-lysine (CML), three isomers of methylglyoxal-hydroimidazolones (MG-Hs), three isomers of glyoxal-hydroimidazolones (GO-Hs), and argpyrimidine were quantified by using HPLC-MS/MS with isotope-labelled internal standard. Results showed that each AGE during the drying process of 150 °C was significantly higher (p < 0.05) than at 90 and 120 °C, and argpyrimidine was only found in the treatment of 150 °C. MG-H1/3 was first quantified as the major AGE during drying at 120-150 °C, the content respectively reached to (39.66 ± 2.61) µg/g and (58.88 ± 1.76) µg/g after 1 h drying, where CML content only had (19.86 ± 1.02) µg/g and (23.71 ± 1.40) µg/g. This study indicated that arginine derived-AGEs are the key components of black tea AGEs.


Assuntos
Camellia sinensis/química , Produtos Finais de Glicação Avançada/análise , Imidazóis/química , Lisina/análogos & derivados , Extratos Vegetais/química , Aldeído Pirúvico/química , Cromatografia Líquida de Alta Pressão , Dessecação , Manipulação de Alimentos , Humanos , Isomerismo , Lisina/química , Folhas de Planta/química , Espectrometria de Massas em Tandem , Chá
15.
J Chromatogr A ; 1625: 461331, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709357

RESUMO

In this work, a novel imidazolium bonding method was proposed for the synthesis of hydrophilic interaction liquid chromatography (HILIC) stationary phases. One obtained stationary phase (SilprAprImCl) was derived from direct reaction between N-(3-aminopropyl)-imidazole and 3-chloropropylated silica gel. Other two materials (SilprAprImBF4 and SilprAprImTf2N) were obtained from SilprAprImCl by ion exchange reaction, respectively. Fourier-transform infrared spectroscopy and elemental analysis afforded the proofs of successful imidazolium immobilization and satisfied bonding efficiency. Various polar compounds such as saccharides, nucleosides, and nucleobases were utilized to evaluate the retention behaviours of these materials in HILIC mode. Different effects from mobile composition, column temperature, imidazolium unite and paired anions (Cl-, BF4-, and Tf2N-) in imidazolium were proved and discussed. Separation mechanism and the role of the imidazolium ions were also investigated in mobile phases with different pH. Moreover, chromatographic stability was evaluated by consecutive injections. Finally, the reliability of these stationary phases was demonstrated by the separation of oligosaccharides in real fructooligosaccharides samples.


Assuntos
Cromatografia Líquida/métodos , Interações Hidrofóbicas e Hidrofílicas , Imidazóis/química , Propanóis/química , Ânions , Concentração de Íons de Hidrogênio , Imidazóis/síntese química , Líquidos Iônicos/química , Nucleosídeos/química , Nucleosídeos/isolamento & purificação , Oligossacarídeos/química , Propanóis/síntese química , Reprodutibilidade dos Testes , Temperatura
16.
J Chromatogr A ; 1625: 461299, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709342

RESUMO

The work describes a novel supercritical fluid chromatography method for the separation of four stereoisomers, RZ(+), SZ(-), RE(+) and SE(-) of luliconazole, an antifungal agent on amylose tris[(S)-α-methylbenzyl carbamate] based Chiralpak IH column. The effect of organic modifiers (methanol, ethanol and isopropanol), column temperature and back pressure were evaluated for their selective separation. A consistent elution order, RZ(+) > SZ(-) > RE(+) > SE(-) was observed in all the modifiers. Amongst the three modifiers, the best result in terms of selectivity, resolution and analysis time was obtained with isopropanol. Analytical separation (Rs > 1.5) of RZ(+) and SZ(-) & RE(+) and SE(-) pairs was achieved with a mobile phase consisting of CO2: isopropanol (80: 20, v/v) within 5.0 min. The retention of isomers increased with increase in temperature and decreased with increase in pressure, which was more prominent for RE(+) and SE(-) isomers. The van't Hoff plots revealed that the chiral separation process was essentially entropy driven. Molecular docking was performed to understand the type of chiral recognition between the stereoisomers and the chiral stationary phase and to understand their elution orders under optimized conditions. The results suggested hydrogen bonding and π-π interactions, as the dominant interaction modes. The elution order and binding energy of the interactions were in good agreement with the experimental results. Quantitative studies of RE(+) luliconazole the pharmacologically active isomer was also performed using a marketed formulation.


Assuntos
Cromatografia com Fluido Supercrítico/métodos , Imidazóis/química , Imidazóis/isolamento & purificação , Simulação de Acoplamento Molecular , Entropia , Ligação de Hidrogênio , Fenilcarbamatos/química , Pressão , Reprodutibilidade dos Testes , Estereoisomerismo , Termodinâmica
17.
J Chromatogr A ; 1624: 461264, 2020 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-32540086

RESUMO

Gas-liquid chromatography is an effective method to determine infinite dilution activity coefficients (γ∞). Wall-coated open-tubular (WCOT) column which offers more advantages over packed column should be a preferable column type; however, the small carrier gas flow rate and stationary phase amount in WCOT columns limit its application in the determination of γ∞. Mathematical strategy made some progress to avoid the quantification problem in the determination of γ∞ by static-wall-coated open-tubular (SWCOT) columns. However, the previously reported strategy was based on the assumption that SWCOT column was geometrically an ideal hollow cylinder, which indeed deviates from the reality. In this study, without that assumption, we derived a new microgeometry-independent equation by using the relationship between the hold-up volume (VM) and the volume of stationary phase (VL), and used it to measure the γ∞ of various organic solutes in two ionic liquids (ILs) 1­butyl­3-methylimidazolium dicyanamide and 1,3-dibutyronitrile-imidazolium bis((trifluoromethyl)sulfonyl)imide, both of which contain double cyano groups in the anion or cation. Phase loading study was adopted to eliminate the influence of interfacial adsorption to partition. The infinite dilution partial molar excess enthalpy, selectivity and capacity were directly calculated from the experimental γ∞ values, and the linear solvation energy relationship (LSER) model was used to characterize the specific properties of both ILs. This new established equation will promote the application of SWCOT columns in thermodynamic measurement and benefit the fast screening of novel solvents for chemical separation processes.


Assuntos
Cromatografia Gasosa/métodos , Adsorção , Imidazóis/química , Líquidos Iônicos/química , Dióxido de Silício/química , Cloreto de Sódio/química , Soluções , Solventes , Termodinâmica
18.
Proc Natl Acad Sci U S A ; 117(24): 13267-13274, 2020 06 16.
Artigo em Inglês | MEDLINE | ID: mdl-32487725

RESUMO

Continuous reaction networks, which do not rely on purification or timely additions of reagents, serve as models for chemical evolution and have been demonstrated for compounds thought to have played important roles for the origins of life such as amino acids, hydroxy acids, and sugars. Step-by-step chemical protocols for ribonucleotide synthesis are known, but demonstrating their synthesis in the context of continuous reaction networks remains a major challenge. Herein, compounds proposed to be important for prebiotic RNA synthesis, including glycolaldehyde, cyanamide, 2-aminooxazole, and 2-aminoimidazole, are generated from a continuous reaction network, starting from an aqueous mixture of NaCl, NH4Cl, phosphate, and HCN as the only carbon source. No well-timed addition of any other reagents is required. The reaction network is driven by a combination of γ radiolysis and dry-down. γ Radiolysis results in a complex mixture of organics, including the glycolaldehyde-derived glyceronitrile and cyanamide. This mixture is then dried down, generating free glycolaldehyde that then reacts with cyanamide/NH3 to furnish a combination of 2-aminooxazole and 2-aminoimidazole. This continuous reaction network models how precursors for generating RNA and other classes of compounds may arise spontaneously from a complex mixture that originates from simple reagents.


Assuntos
Evolução Química , Modelos Químicos , RNA/química , RNA/síntese química , Acetaldeído/análogos & derivados , Acetaldeído/síntese química , Acetaldeído/química , Cianamida/síntese química , Cianamida/química , Raios gama , Imidazóis/síntese química , Imidazóis/química , Origem da Vida , Oxazóis/síntese química , Oxazóis/química , Fotoquímica , Água/química
19.
J Chromatogr A ; 1623: 461175, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505279

RESUMO

An ionic liquid hybrid zwitterionic polymer capillary microextraction (CME) column was prepared for the biomimetic enrichment of glycopeptides by one-step copolymerization of 2-methacryloyloxyethyl phosphorylcholine (MPC) and 1-butyl-3-vinylimidazolium bromide, in the presence of crosslinker trimethylolpropane trimethacrylate (TMA). The resultant monolith was characterized by scanning electron microscopy (SEM), fourier transform infrared (FT-IR) spectroscopy and pore size distribution measurement. Due to the incorporation of zwitterionic MPC owning a unique biomimic structure (i.e. hydrophilic cation/anion and hydrophobic long-alkyl chain), the monolithic column has large pore size and good biocompatibility, exhibiting high extraction efficiency, permeability and fast mass transfer to targets. Besides, the use of ionic liquids (ILs) as co-monomer in the polymerization endows the monolith with enhanced mechanical stability, uniformity and multiple interactions. The prepared column was successfully applied in CME coupled to capillary electrochromatography (CEC) for the efficient enrichment and separation of glycopeptide antibiotics in foodstuff. The method demonstrated a wide linear range (50.0-18000.0 µg L-1), low detection limits (5.0-10.0 µg L-1, S/N = 3) and satisfied recoveries (76.0-109.7%). This work shows the advantage of fine-tuning biomimetic monoliths in application-specific CME-CEC.


Assuntos
Antibacterianos/análise , Eletrocromatografia Capilar/métodos , Glicopeptídeos/análise , Líquidos Iônicos/química , Antibacterianos/isolamento & purificação , Materiais Biomiméticos , Fracionamento Químico , Análise de Alimentos/métodos , Glicopeptídeos/isolamento & purificação , Interações Hidrofóbicas e Hidrofílicas , Imidazóis/química , Metacrilatos/química , Microscopia Eletrônica de Varredura , Fosforilcolina/análogos & derivados , Fosforilcolina/química , Polimerização , Polímeros/química , Espectroscopia de Infravermelho com Transformada de Fourier , Compostos de Vinila/química
20.
J Chromatogr A ; 1623: 461192, 2020 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-32505285

RESUMO

An imidazolium ionic-liquid-modified phenolic resin (ILPR) was synthesized using 3-aminophenol as a functional monomer, glyoxylic acid as a green cross-linker, and polyethylene glycol 6000 as a porogen. The obtained ILPR showed better extraction of benzoylurea plant hormones thidiazuron and forchlorfenuron than the unmodified phenolic resin because the imidazolium IL provides more interaction modes with the analytes. ILPR, as a tailored adsorbent for solid-phase extraction, was coupled with high-performance liquid chromatography (ILPR‒SPE‒HPLC) for the simultaneous determination of thidiazuron and forchlorfenuron in cucumbers. Good linearity of the ILPR‒SPE‒HPLC method was obtained, ranging from 0.0100 to 5.00 µg g-1 with a correlation coefficient (r) ≥ 0.9999. The recoveries of spiked samples ranged from 91.4% to 100.7% with a relative standard deviation of ≤ 6.0%.


Assuntos
Cucumis sativus/química , Formaldeído/química , Imidazóis/química , Líquidos Iônicos/química , Fenóis/química , Compostos de Fenilureia/isolamento & purificação , Polímeros/química , Piridinas/isolamento & purificação , Extração em Fase Sólida/métodos , Tiadiazóis/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Formaldeído/síntese química , Líquidos Iônicos/síntese química , Cinética , Fenóis/síntese química , Polímeros/síntese química , Reprodutibilidade dos Testes
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