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1.
Langmuir ; 40(21): 11134-11145, 2024 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-38749057

RESUMO

One of the world's challenging energy issues is introducing practical and affordable technology for organosulfur removal in fuel. Adsorptive desulfurization (ADS) can address this issue if highly effective activated carbon (AC) derived from industrial waste with excellent textural properties is used. In this study, the derived ACs from glycerin pitch loaded with P and Fe (AC/P and AC/Fe) were used as adsorbents for the ADS of model fuel oils, such as dibenzothiophene (DBT) at mild operating conditions. Under the optimized experimental conditions, 0.3 g of adsorbent dosage, 60 min reaction time, 30 °C temperature, and pH 4, the maximal DBT removal of 96.28 and 43.64%, respectively, for AC/P and AC/Fe was realized. The results indicated that the phosphorus-doped AC/P increases the selectivity of the ADS mechanism for DBT removal. Kinetic investigations disclosed that the adsorption process follows second-pseudo-order kinetics and the Langmuir adsorption isotherm model. The adsorbents remained active for five successive reuses, indicating their robust real-world applications. The electrochemical properties of the fabricated carbon electrodes were analyzed via cyclic voltammetry by coating the ACs with polytetrafluoroethylene (PTFE) as a binder. The transition-metal-doped AC/Fe, though exhibiting 5 times lower surface area, showed the highest specific capacitance at a scan rate of 5 mVs-1 (0.65 µF cm-2). Similarly, the extended AC:PTFE capacitor at a 10% binder ratio offered the maximum capacitance value (1.13 µF cm-2). The synthesized ACs demonstrated potential application as an electrode material, and hence glycerin pitch could be a low-cost precursor to improve the feasibility of commercial production of AC.

2.
J Sep Sci ; 45(15): 2865-2876, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35661411

RESUMO

A vortex-assisted surfactant enhanced emulsification liquid-liquid microextraction based on non-ionic silicone surfactant was successfully developed for the determination of organophosphorus pesticides in food samples coupled to gas chromatography-mass spectrometry. A new type of non-ionic silicone surfactant composed of polysiloxane chains was employed as a green emulsifier to facilitate the emulsification of extraction solvent into the sample matrix, thereby intensifying the mass transfer of target analytes into the organic phase. The variables that affect the extraction were systematically optimized: 80 µl of hexane and 0.5% (v/v) of silicone surfactant were used as extraction solvent and surfactant respectively, the solution was mixed well under vortex agitation for 1 min with the addition of 4% (w/v) sodium sulfate. Under optimum conditions, the linearity of the method was obtained in the range of 0.1-200 µg/kg with a good coefficient of determination varying from 0.9986 to 0.9996. The limit of detection and the limit of quantitation were between 0.008-0.1 and 0.02-0.3 µg/kg, respectively. Application of the proposed method to real samples gave satisfactory recovery values (80%-118%) for the target analytes. The suggested approach has also proven to be convenient, expeditious, and environmentally benign.


Assuntos
Mel , Microextração em Fase Líquida , Resíduos de Praguicidas , Praguicidas , Frutas/química , Mel/análise , Microextração em Fase Líquida/métodos , Compostos Organofosforados/análise , Resíduos de Praguicidas/análise , Praguicidas/análise , Silicones , Solventes/química , Tensoativos/química
3.
Chirality ; 33(1): 37-50, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33197086

RESUMO

A chiral separation method coupled with capillary electrophoresis (CE) analysis for ketoconazole and miconazole enantiomers using chiral selectors such as ß-cyclodextrin (ß-CD) and hydroxypropyl-ß-CD (HP-ß-CD) was developed in this study, which included the optimisation, validation and application of the method on the antifungal cream samples. The formation of inclusion complex between the hosts (ß-CD and HP-ß-CD) and guests (ketoconazole and miconazole) were compared and analysed using ultraviolet-visible spectrophotometry, nuclear magnetic resonance (NMR) spectroscopy and molecular docking methods. Results from the study showed that in a concentration that ranged between 0.25 and 50 mg L-1 , the linear calibration curves of each enantiomer had a high coefficient of regression (R2 > 0.999), low limit of detection (0.075 mg L-1 ) and low limit of quantification (0.25 mg L-1 ). The relative standard deviation (RSD) of the intraday and interday analyses ranged from 0.79% to 8.01% and 3.30% to 11.43%, respectively, while the recoveries ranged from 82.0% to 105.7% (RSD < 7%, n = 3). The most probable structure of the inclusion complexes was proposed based on the findings from the molecular docking studies conducted using the PatchDock server.

4.
Biomed Chromatogr ; 35(5): e5050, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33314228

RESUMO

A simple and sensitive preconcentration strategy using sequential electrokinetic and hydrodynamic injection modes in micellar electrokinetic chromatography with diode array detection was developed and applied for the separation and determination of anticancer agent, 5-fluorouracil and its metabolite, 5-fluoro-2'-deoxyuridine, in human plasma. Sequential injection modes with increased analyte loading capacity using the anionic pseudo-stationary phase facilitated collection of the dispersed neutral and charged analytes into narrow zones and improved sensitivity. Several important parameters affecting sample enrichment performance were evaluated and optimized in this study. Under the optimized experimental conditions, 614- and 643-fold and 782- and 803-fold sensitivity improvement were obtained for 5-fluorouracil and its metabolite when compared with normal hydrodynamic and electrokinetic injection, respectively. The method has good linearity (1-1,000 ng/ml) with acceptable coefficient of determination (r2 > 0.993), low limits of detection (0.11-0.14 ng/ml) and satisfactory analyte relative recovery (97.4-99.7%) with relative standard deviations of 4.6-9.3% (n = 6). Validation results as well as the application to analysis of human plasma samples from cancer patients demonstrate the applicability of the proposed method to clinical studies.


Assuntos
Antineoplásicos/sangue , Cromatografia Capilar Eletrocinética Micelar/métodos , Desoxiuridina/análogos & derivados , Fluoruracila/sangue , Desoxiuridina/sangue , Humanos
5.
Molecules ; 26(9)2021 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-33923041

RESUMO

In this work, mesoporous TiO2-modified ZnO quantum dots (QDs) were immobilised on a linear low-density polyethylene (LLDPE) polymer using a solution casting method for the photodegradation of tetracycline (TC) antibiotics under fluorescent light irradiation. Various spectroscopic and microscopic techniques were used to investigate the physicochemical properties of the floating hybrid polymer film catalyst (8%-ZT@LLDPE). The highest removal (89.5%) of TC (40 mg/L) was achieved within 90 min at pH 9 due to enhanced water uptake by the LDDPE film and the surface roughness of the hybrid film. The formation of heterojunctions increased the separation of photogenerated electron-hole pairs. The QDs size-dependent quantum confinement effect leads to the displacement of the conduction band potential of ZnO QDs to more negative energy values than TiO2. The displacement generates more reactive species with higher oxidation ability. The highly stable film photocatalyst can be separated easily and can be repeatedly used up to 8 cycles without significant loss in the photocatalytic ability. The scavenging test indicates that the main species responsible for the photodegradation was O2●-. The proposed photodegradation mechanism of TC was demonstrated in further detail based on the intermediates detected by LC-time-of-flight/mass spectrometry (LC/TOF-MS).


Assuntos
Fluorescência , Fotólise , Polímeros/química , Tetraciclina/química , Polietileno/química , Tetraciclina/efeitos adversos , Titânio/química , Óxido de Zinco/química
6.
J Sep Sci ; 43(16): 3294-3303, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32519432

RESUMO

In this work, a simple, fast, sensitive, and environmentally friendly method was developed for preconcentration and quantitative measurement of bisphenol A in water samples using gas chromatography with mass spectrometry. The preconcentration approach, namely biosorption-based dispersive liquid-liquid microextraction with extractant removal by magnetic nanoparticles was performed based on the formation of microdroplet of rhamnolipid biosurfactant throughout the aqueous samples, which accelerates the mass transfer process between the extraction solvent and sample solution. The process is then followed by the application of magnetic nanoparticles for easy retrieval of the analyte-containing extraction solvent. Several important variables were optimized comprehensively including type of disperser solvent and desorption solvent, rhamnolipid concentration, volume of disperser solvent, amount of magnetic nanoparticles, extraction time, desorption time, ionic strength, and sample pH. Under the optimized microextraction and gas chromatography with mass spectrometry conditions, the method demonstrated good linearity over the range of 0.5-500 µg/L with a coefficient of determination of R2  = 0.9904, low limit of detection (0.15 µg/L) and limit of quantification (0.50 µg/L) of bisphenol A, good analyte recoveries (84-120%) and acceptable relative standard deviation (1.8-14.9%, n = 6). The proposed method was successfully applied to three environmental water samples, and bisphenol A was detected in all samples.

7.
Molecules ; 25(18)2020 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-32971740

RESUMO

A bottom-up approach for synthesizing silver nanoparticles (AgNPs-GA) phytomediated by Garcinia atroviridis leaf extract is described. Under optimized conditions, the AgNPs-GA were synthesized at a concentration of 0.1 M silver salt and 10% (w/v) leaf extract, 1:4 mixing ratio of reactants, pH 3, temperature 32 °C and 72 h reaction time. The AgNPs-GA were characterized by various analytical techniques and their size was determined to be 5-30 nm. FTIR spectroscopy indicates the role of phenolic functional groups in the reduction of silver ions into AgNPs-GA and in supporting their subsequent stability. The UV-Visible spectrum showed an absorption peak at 450 nm which reflects the surface plasmon resonance (SPR) of AgNPs-GA and further supports the stability of these biosynthesized nanoparticles. SEM, TEM and XRD diffractogram analyses indicate that AgNPs-GA were spherical and face-centered-cubic in shape. This study also describes the efficacy of biosynthesized AgNPs-GA as anti-proliferative agent against human breast cancer cell lines, MCF-7 and MCF-7/TAMR-1. Our findings indicate that AgNPs-GA possess significant anti-proliferative effects against both the MCF-7 and MCF-7/TAMR-1 cell lines, with inhibitory concentration at 50% (IC50 values) of 2.0 and 34.0 µg/mL, respectively, after 72 h of treatment. An induction of apoptosis was evidenced by flow cytometry using Annexin V-FITC and propidium iodide staining. Therefore, AgNPs-GA exhibited its anti-proliferative activity via apoptosis on MCF-7 and MCF-7/TAMR-1 breast cancer cells in vitro. Taken together, the leaf extract from Garcinia atroviridis was found to be highly capable of producing AgNPs-GA with favourable physicochemical and biological properties.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Neoplasias da Mama/patologia , Nanopartículas Metálicas/química , Prata/química , Prata/farmacologia , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Técnicas de Química Sintética , Garcinia/química , Química Verde , Humanos , Células MCF-7 , Extratos Vegetais/química
8.
J Sep Sci ; 41(19): 3751-3763, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30125466

RESUMO

This study describes a dispersive liquid-liquid microextraction combined with dispersive solid-phase extraction method based on phenyl-functionalized magnetic sorbent for the preconcentration of polycyclic aromatic hydrocarbons from environmental water, sugarcane juice, and tea samples prior to gas chromatography with mass spectrometry analysis. Several important parameters affecting the extraction efficiency were investigated thoroughly, including the mass of sorbent, type and volume of extraction solvent, extraction time, type of desorption solvent, desorption time, type and amount of salt-induced demulsifier, and sample volume. Under the optimized extraction and gas chromatography-mass spectrometric conditions, the method revealed good linearity (10-100000 ng/L) with coefficient of determination (R2 ) of ≥0.9951, low limits of detection (3-16 ng/L), high enrichment factors (61-239), and satisfactory analyte recoveries (86.3-109.1%) with the relative standard deviations < 10% (n = 5). The entire sample preparation procedure was simple, rapid and can be accomplished within 10 min. This method was applied (after pretreatment) to 30 selected samples, and the presence of studied analytes was quantified in 17 samples.

9.
J Sep Sci ; 41(14): 2942-2951, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29877605

RESUMO

We describe the preparation, characterization, and application of a composite film adsorbent based on blended agarose-chitosan-multiwalled carbon nanotubes for the preconcentration of selected nonsteroidal anti-inflammatory drugs in aqueous samples before determination by high performance liquid chromatography with ultraviolet detection. The composite film showed a high surface area (4.0258 m2 /g) and strong hydrogen bonding between the multiwalled carbon nanotubes and agarose/chitosan matrix, which prevent adsorbent deactivation and ensure long-term stability. Several parameters, such as sample pH, addition of salt, extraction time, desorption solvent, and concentration of multiwalled carbon nanotubes in the composite film were optimized using a one-factor-at-time approach. The optimum extraction conditions obtained were as follows: isopropanol as conditioning solvent, 10 mL of sample solution at pH 2, extraction time of 30 min, stirring speed of 600 rpm, 100 µL of isopropanol as desorption solvent, desorption time of 5 min under ultrasonication, and 0.4% w/v of composite film. Under the optimized conditions, the calibration curve showed good linearity in the range of 1-500 ng/mL (r2  = 0.997-0.999), and good limits of detection (0.89-8.05 ng/mL) were obtained with good relative standard deviations of < 4.59% (n = 3) for the determination of naproxen, diclofenac sodium salt, and mefenamic acid drugs.

10.
Int J Mol Sci ; 19(6)2018 06 11.
Artigo em Inglês | MEDLINE | ID: mdl-29891772

RESUMO

In the field of medicine, nanomaterials, especially those derived using the green method, offer promise as anti-cancer agents and drug carriers. However, the biosafety of metallic nanoparticles used as anti-cancer agents remains a concern. The goal of this systematic review was to compare the cytotoxicity of different plant-mediated syntheses of metallic nanoparticles based on their potency, therapeutic index, and cancer cell type susceptibility in the hopes of identifying the most promising anti-cancer agents. A literature search of electronic databases including Science Direct, PubMed, Springer Link, Google Scholar, and ResearchGate, was conducted to obtain research articles. Keywords such as biosynthesis, plant synthesis, plant-mediated, metallic nanoparticle, cytotoxicity, and anticancer were used in the literature search. All types of research materials that met the inclusion criteria were included in the study regardless of whether the results were positive, negative, or null. The therapeutic index was used as a safety measure for the studied compound of interest. Data from 76 selected articles were extracted and synthesised. Seventy-two studies reported that the cytotoxicity of plant-mediated synthesis of metallic nanoparticles was time and/or dose-dependent. Biosynthesised silver nanoparticles demonstrated higher cytotoxicity potency compared to gold nanoparticles synthesised by the same plants (Plumbago zeylanica, Commelina nudiflora, and Cassia auriculata) irrespective of the cancer cell type tested. This review also identified a correlation between the nanoparticle size and morphology with the potency of cytotoxicity. Cytotoxicity was found to be inversely proportional to nanoparticle size. The plant-mediated syntheses of metallic nanoparticles were predominantly spherical or quasi-spherical, with the median lethal dose of 1⁻20 µg/mL. Nanoparticles with other shapes (triangular, hexagonal, and rods) were less potent. Metallic nanoparticles synthesised by Abutilon inducum, Butea monosperma, Gossypium hirsutum, Indoneesiella echioides, and Melia azedarach were acceptably safe as anti-cancer agents, as they had a therapeutic index of >2.0 when tested on both cancer cells and normal human cells. Most plant-mediated syntheses of metallic nanoparticles were found to be cytotoxic, although some were non-cytotoxic. The results from this study suggest a focus on a selected list of potential anti-cancer agents for further investigations of their pharmacodynamic/toxicodynamic and pharmacokinetic/toxicokinetic actions with the goal of reducing the Global Burden of Diseases and the second leading cause of mortality.


Assuntos
Ouro/toxicidade , Nanopartículas Metálicas/toxicidade , Plantas/metabolismo , Animais , Humanos , Tamanho da Partícula
11.
J Sep Sci ; 40(21): 4222-4233, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28837263

RESUMO

A new facile magnetic micro-solid-phase extraction coupled to gas chromatography and mass spectrometry detection was developed for the extraction and determination of selected antidepressant drugs in biological fluids using magnetite-MCM-41 as adsorbent. The synthesized sorbent was characterized by several spectroscopic techniques. The maximum extraction efficiency for extraction of 500 µg/L antidepressant drugs from aqueous solution was obtained with 15 mg of magnetite-MCM-41 at pH 12. The analyte was desorbed using 100 µL of acetonitrile prior to gas chromatography determination. This method was rapid in which the adsorption procedure was completed in 60 s. Under the optimized conditions using 15 mL of antidepressant drugs sample, the calibration curve showed good linearity in the range of 0.05-500 µg/L (r2  = 0.996-0.999). Good limits of detection (0.008-0.010 µg/L) were obtained for the analytes with good relative standard deviations of <8.0% (n = 5) for the determination of 0.1, 5.0, and 500.0 µg/L of antidepressant drugs. This method was successfully applied to the determination of amitriptyline and chlorpromazine in plasma and urine samples. The recoveries of spiked plasma and urine samples were in the range of 86.1-115.4%. Results indicate that magnetite micro-solid-phase extraction with gas chromatography and mass spectrometry is a convenient, fast, and economical method for the extraction and determination of amitriptyline and chlorpromazine in biological samples.


Assuntos
Antidepressivos/sangue , Antidepressivos/urina , Óxido Ferroso-Férrico , Dióxido de Silício , Amitriptilina/sangue , Amitriptilina/urina , Clorpromazina/sangue , Clorpromazina/urina , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Nanopartículas de Magnetita , Extração em Fase Sólida
12.
Biomed Chromatogr ; 31(2)2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27474795

RESUMO

A rapid dispersive micro-solid phase extraction (D-µ-SPE) combined with LC/MS/MS method was developed and validated for the determination of ketoconazole and voriconazole in human urine and plasma samples. Synthesized mesoporous silica MCM-41 was used as sorbent in d-µ-SPE of the azole compounds from biological fluids. Important D-µ-SPE parameters, namely type desorption solvent, extraction time, sample pH, salt addition, desorption time, amount of sorbent and sample volume were optimized. Liquid chromatographic separations were carried out on a Zorbax SB-C18 column (2.1 × 100 mm, 3.5 µm), using a mobile phase of acetonitrile-0.05% formic acid in 5 mm ammonium acetate buffer (70:30, v/v). A triple quadrupole mass spectrometer with positive ionization mode was used for the determination of target analytes. Under the optimized conditions, the calibration curves showed good linearity in the range of 0.1-10,000 µg/L with satisfactory limit of detection (≤0.06 µg/L) and limit of quantitation (≤0.3 µg/L). The proposed method also showed acceptable intra- and inter-day precisions for ketoconazole and voriconazole from urine and human plasma with RSD ≤16.5% and good relative recoveries in the range 84.3-114.8%. The MCM-41-D-µ-SPE method proved to be rapid and simple and requires a small volume of organic solvent (200 µL); thus it is advantageous for routine drug analysis.


Assuntos
Antifúngicos/sangue , Antifúngicos/urina , Cetoconazol/sangue , Cetoconazol/urina , Microextração em Fase Sólida/métodos , Voriconazol/sangue , Voriconazol/urina , Cromatografia Líquida de Alta Pressão/economia , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Limite de Detecção , Dióxido de Silício/química , Microextração em Fase Sólida/economia , Espectrometria de Massas em Tandem/economia , Espectrometria de Massas em Tandem/métodos
13.
Carbohydr Polym ; 338: 122199, 2024 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-38763725

RESUMO

Deep eutectic solvents (DES) emerge as promising alternatives to conventional solvents, offering outstanding extraction capabilities, low toxicity, eco-friendliness, straightforward synthesis procedures, broad applicability, and impressive recyclability. DES are synthesized by combining two or more components through various synthesis procedures, such as heat-assisted mixing/stirring, grinding, freeze drying, and evaporation. Polysaccharides, as abundant natural materials, are highly valued for their biocompatibility, biodegradability, and sustainability. These versatile biopolymers can be derived from various natural sources such as plants, algae, animals, or microorganisms using diverse extraction techniques. This review explores the synthesis procedures of DES, their physicochemical properties, characterization analysis, and their application in polysaccharide extraction. The extraction optimization strategies, parameters affecting DES-based polysaccharide extraction, and separation mechanisms are comprehensively discussed. Additionally, this review provides insights into recently developed molecular guides for DES screening and the utilization of artificial neural networks for optimizing DES-based extraction processes. DES serve as excellent extraction media for polysaccharides from different sources, preserving their functional features. They are utilized both as extraction solvents and as supporting media to enhance the extraction abilities of other solvents. Continued research aims to improve DES-based extraction methods and achieve selective, energy-efficient processes to meet the demands of this expanding field.


Assuntos
Solventes Eutéticos Profundos , Polissacarídeos , Polissacarídeos/química , Polissacarídeos/isolamento & purificação , Solventes Eutéticos Profundos/química , Produtos Biológicos/química , Produtos Biológicos/isolamento & purificação , Animais , Solventes/química , Fracionamento Químico/métodos , Plantas/química
14.
Crit Rev Anal Chem ; 53(4): 906-927, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-34693833

RESUMO

Despite organophosphorus pesticides (OPPs) benefits in controlling vector-borne diseases and noxious insects, the bioaccumulation and persistence in the soil system may metamorphose into new substances which could pose a serious threat to the ecosystems and human health. The generally low levels of OPPs residues and often the complexity of the soil matrix are the issues that researcher must deal with. Thus, it is essential to isolate and preconcentrate the OPPs from the matrix to reduce interference effects to obtain a reliable detection. Researchers have reported sample preparation techniques as a promising approach to improve analytical measurement of merits including recovery, precision, linearity, limit of detection, and limit of quantification. Under the selected conditions, limits of detection range between 0.001 and 143 ng/mL, and extraction recovery range between 5 and 154% were obtained. This review evaluates the challenges and opportunities, emphasizes the prospects of sampling techniques and various (micro)extraction coupled with chromatographic methods in different soil samples. Based on the finding, the extraction efficiency depended largely on the interaction between OPPs and extraction media. The fate, migration, toxicity impact, sampling procedure, and storage which influenced the sample preparation were comprehensively discussed.


Assuntos
Praguicidas , Poluentes Químicos da Água , Humanos , Praguicidas/análise , Compostos Organofosforados/análise , Solo , Ecossistema , Poluentes Químicos da Água/análise
15.
Food Chem ; 396: 133670, 2022 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-35853378

RESUMO

The current study discussed the use of silicone surfactant-based deep eutectic solvent as a surface modifier for magnetic iron particles (Fe3O4) to produce a novel adsorbent and its application for the extraction of organophosphorus pesticides (OPPs) in vegetable samples. A deep eutectic solvent (DES) was prepared using low toxic and inexpensive substances such as silicone surfactant (SS) and dodecanoic acid (DoAc). This new eco-friendly SS:DoAc based DES was explored as a substitution to traditional organic reagents for surface modification of Fe3O4 to increase the adsorption capacity and to reduce the matrix interferences, hazardous waste generation and environmental pollution. The newly synthesized SS:DoAc@Fe3O4 adsorbent was successfully characterized and applied in magnetic solid phase extraction (MSPE). Under optimized conditions, the proposed approach exhibited excellent linearity ranging from 0.1 to 200 µg/kg (R2 ≥ 0.9970), low detection limit (0.03-0.1 µg/kg) and acceptable relative recovery (80-119 %) for the studied OPPs.


Assuntos
Praguicidas , Cromatografia Gasosa , Solventes Eutéticos Profundos , Ferro , Limite de Detecção , Fenômenos Magnéticos , Compostos Organofosforados , Praguicidas/análise , Silicones , Tensoativos , Verduras
16.
Food Chem ; 372: 131220, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-34607048

RESUMO

A simple and sensitive method for the determination of bisphenol A and its analogues at the ng/mL level in bottled tea beverages is presented. This method utilized a dynamic pH junction to focus the analyte into a more concentrated zone, based on the electrophoretic mobility difference of analytes in the sample matrix and background electrolytes in capillary electrophoresis coupled to mass spectrometry (CE-MS). The optimised analyte focusing led to enhanced signal detection with average peak heights for five bisphenols of 53-170 folds higher than conventional injections. Under optimised conditions, the method showed good linearity in the range of 0.1-100 ng/mL, excellent limits of detection (0.03-0.04 ng/mL), good analyte recovery (80.3-118.1%) with acceptable relative standard deviations (<12%). The limits of quantifications were below the maximum permissible content of bisphenol A set by the European Commission for this product. This method was used to quantitatively analyse bisphenols in six different kinds of bottled tea beverages, making it a promising tool for practical applications.


Assuntos
Bebidas , Eletroforese Capilar , Compostos Benzidrílicos , Concentração de Íons de Hidrogênio , Espectrometria de Massas , Fenóis , Chá
17.
Polymers (Basel) ; 14(24)2022 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-36559892

RESUMO

Water pollution issues, particularly those caused by heavy metal ions, have been significantly growing. This paper combined biopolymers such as sodium alginate (SA) and ß-cyclodextrin (ß-CD) to improve adsorption performance with the help of calcium ion as the cross-linked agent. Moreover, the addition of carbon nanotubes (CNTs) into the hybrid hydrogel matrix was examined. The adsorption of nickel(II) was thoroughly compared between pristine sodium alginate/ß-cyclodextrin (SA-ß-CD) and sodium alginate/ß-cyclodextrin immobilized carbon nanotubes (SA-ß-CD/CNTs) hydrogel. Both hydrogels were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) spectral analysis, field emission scanning electron microscopy (FESEM), electron dispersive spectroscopy (EDX), thermogravimetric analysis (TGA) and Brunauer-Emmett-Teller (BET) surface area analysis. The results showed SA-ß-CD/CNTs hydrogel exhibits excellent thermal stability, high specific surface area and large porosity compared with SA-ß-CD hydrogel. Batch experiments were performed to study the effect of several adsorptive variables such as initial concentration, pH, contact time and temperature. The adsorption performance of the prepared SA-ß-CD/CNTs hydrogel was comprehensively reported with maximum percentage removal of up to 79.86% for SA-ß-CD/CNTs and 69.54% for SA-ß-CD. The optimum adsorption conditions were reported when the concentration of Ni(II) solution was maintained at 100 ppm, pH 5, 303 K, and contacted for 120 min with a 1000 mg dosage. The Freundlich isotherm and pseudo-second order kinetic model are the best fits to describe the adsorption behavior. A thermodynamic study was also performed. The probable interaction mechanisms that enable the successful binding of Ni(II) on hydrogels, including electrostatic attraction, ion exchange, surface complexation, coordination binding and host-guest interaction between the cationic sites of Ni(II) on both SA-ß-CD and SA-ß-CD/CNTs hydrogel during the adsorption process, were discussed. The regeneration study also revealed the high efficiency of SA-ß-CD/CNTs hydrogel on four successive cycles compared with SA-ß-CD hydrogel. Therefore, this work signifies SA-ß-CD/CNTs hydrogel has great potential to remove Ni(II) from an aqueous environment compared with SA-ß-CD hydrogel.

18.
Food Chem ; 368: 130835, 2022 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-34416487

RESUMO

A novel deep eutectic solvents (DES) was successfully applied as an emulsifier in vortex assisted liquid-liquid microextraction (VALLME) coupled with gas chromatography-mass spectrometry for the determination of organophosphorus pesticides in honey and fruit samples. Based on the result of toxicity study, DES provides new opportunities for the safe delivery and application. The predominant parameters affecting extraction efficiency were thoroughly optimized and studied in detail. Under optimum parameters, the calibration curve was determined in the concentration range of 0.1 to 200 µgL-1 with excellent determination coefficients values of 0.9989 to 0.9999. Limit of detection and limit of quantification were found to be 0.01 - 0.09 µgL-1 and 0.03 - 0.2 µgL-1, respectively. Application of the developed method to honey and fruit samples gave acceptable recovery values 83 - 109% with relative standard deviation below than 9.5%. The suggested approach has also proven to be simple, cost-effective, rapid, and non-toxic in nature.


Assuntos
Mel , Microextração em Fase Líquida , Praguicidas , Frutas/química , Mel/análise , Limite de Detecção , Compostos Organofosforados/toxicidade , Praguicidas/análise , Praguicidas/toxicidade , Solventes
19.
Pharmaceuticals (Basel) ; 15(10)2022 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-36297340

RESUMO

The development of new antibiotics is urgently needed to combat the threat of bacterial resistance. New classes of compounds that have novel properties are urgently needed for the development of effective antimicrobial agents. The extract of Cannabis sativa L. has been used to treat multiple ailments since ancient times. Its bioactivity is largely attributed to the cannabinoids found in its plant. Researchers are currently searching for new anti-infective agents that can treat various infections. Although its phytocannabinoid ingredients have a wide range of medical benefits beyond the treatment of infections, they are primarily associated to psychotropic effects. Different cannabinoids have been demonstrated to be helpful against harmful bacteria, including Gram-positive bacteria. Moreover, combination therapy involving the use of different antibiotics has shown synergism and broad-spectrum activity. The purpose of this review is to gather current data on the actions of Cannabis sativa (C. sativa) extracts and its primary constituents such as terpenes and cannabinoids towards pathogens in order to determine their antimicrobial properties and cytotoxic effects together with current challenges and future perspectives in biomedical application.

20.
Chemosphere ; 303(Pt 1): 135075, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35618057

RESUMO

Endocrine disruptor compounds (EDCs) such as plasticisers, surfactants, pharmaceutical products, personal care products and pesticides are frequently released into the environmental waters. Therefore, a sensitive and environmentally friendly method is entailed to quantify these compounds at their trace level concentrations. This study encapsulated the ß-cyclodextrin crosslinked with citric acid in a polypropylene membrane protected-µ-solid phase extraction (BCD-CA µ-SPE) device for preconcentrating the EDCs (triclosan, triclocarban, 2-phenylphenol, 4-tert-octylphenols and bisphenol A) in real water samples before the analysis by high-performance liquid chromatography. FT-IR and TGA results indicated that BCD-CA was successfully synthesised with the formation of ester linkage (1078.33 cm-1) and O-H stretching from carboxylic acid (3434.70 cm-1) with higher thermal stability as compared with native CD with the remaining weight above 72.1% at 500 °C. Several critical parameters such as the sorbent loading, type and amount of salts, extraction time, sample volume, sample pH, type and volume of desorption solvents and desorption time were sequentially optimised and statistically validated. Under the optimum condition, the use of BCD-CA µ-SPE device had manifested good linearity (0.5-500 µg L-1) with the determination of the coefficient range of 0.9807-0.9979. The p-values for the F-test and t-test (6.60 × 10-8 - 1.77 × 10-5) were lesser than 0.05 and low detection limits ranging from 0.27 to 0.84 µg L-1 for all studied EDCs. The developed technique was also successfully applied for EDC analyses in four distinct real water samples, namely, wastewater, river water, tap water and mineral water, with good EDCs recoveries (80.2%-99.9%), low relative standard deviations (0.1%-3.8%, n = 3) with enrichment factor ranging from 9 to 82 folds. These results signified the potential of the BCD-CA µ-SPE device as an efficient, sensitive, and environmentally friendly approach for analyzing EDCs.


Assuntos
Disruptores Endócrinos , Poluentes Químicos da Água , beta-Ciclodextrinas , Cromatografia Líquida de Alta Pressão/métodos , Ácido Cítrico , Disruptores Endócrinos/análise , Limite de Detecção , Polipropilenos/análise , Extração em Fase Sólida/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Água/química , Poluentes Químicos da Água/análise
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