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1.
Molecules ; 24(3)2019 Feb 04.
Artigo em Inglês | MEDLINE | ID: mdl-30720725

RESUMO

In the present study, polymer supported nanocomposites, consisting of bio-based poly(ethylene furanoate) polyester and TiO2 nanoparticles, were prepared and evaluated as effective photocatalysts for anti-inflammatory/analgesic drug removal. Nanocomposites were prepared by the solvent evaporation method containing 5, 10, 15, and 20 wt% TiO2 and characterized using Fourier Transform Infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). Thin films of them have been prepared by the melt press and optimization of the photocatalytic procedure was conducted for the most efficient synthesized photocatalyst. Finally, mineralization was evaluated by means of Total organic carbon (TOC) reduction and ion release, while the transformation products (TPs) generated during the photocatalytic procedure were identified by high-resolution mass spectrometry.


Assuntos
Analgésicos/química , Anti-Inflamatórios não Esteroides/química , Nanocompostos/química , Poliésteres/química , Polietileno/química , Titânio/química , Analgésicos/administração & dosagem , Anti-Inflamatórios não Esteroides/administração & dosagem , Varredura Diferencial de Calorimetria , Catálise , Técnicas de Química Sintética , Evolução Molecular , Processos Fotoquímicos , Polietileno/síntese química , Espectroscopia de Infravermelho com Transformada de Fourier
2.
Sci Total Environ ; 537: 411-20, 2015 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-26282775

RESUMO

The aim of the present study is the evaluation of graphene oxide (GhO) as adsorbent material for the removal of beta-blockers (pharmaceutical compounds) in aqueous solutions. The composition and morphology of prepared materials were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Atenolol (ATL) and propranolol (PRO) were used as model drug molecules and their behavior were investigated in terms of GhO dosage, contact time, temperature and pH. Adsorption mechanisms were proposed and the pH-effect curves after adsorption were discussed. The kinetic behavior of GhO-drugs system was analyzed after fitting to pseudo-first and -second order equations. The adsorption equilibrium data were fitted to Langmuir, Freundlich and Langmuir-Freundlich model calculating the maximum adsorption capacity (67 and 116 mg/g for PRO and ATL (25 °C), respectively). The temperature effect on adsorption was tested carrying out the equilibrium adsorption experiments at three different temperatures (25, 45, 65 °C). Then, the thermodynamic parameters of enthalpy, free energy and entropy were calculated. Finally, the desorption of drugs from GhO was evaluated by using both aqueous eluants (pH2-10) and organic solvents.


Assuntos
Antagonistas Adrenérgicos beta/química , Grafite/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Cinética , Microscopia Eletrônica de Varredura , Termodinâmica
3.
Anal Chim Acta ; 866: 27-40, 2015 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-25732690

RESUMO

In the present study, two novel molecularly imprinted polymers (MIPs) with remarkable recognition properties for metformin and its transformation product, guanylurea, have been prepared for their selective, enrichment, isolation and removal from aqueous media. The prepared adsorbents were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and swelling experiments. The performance of the prepared MIPs was evaluated by various parameters including the influence of pH, contact time, temperature and initial compound concentration. The effects on the adsorption behavior of the removal process parameters were studied and the equilibrium data were fitted by the Langmuir and Freundlich models. Due to the imprinting effect, adsorption performance of MIPs was always superior to its corresponding NIP (non-imprinted polymer), with maximum adsorption capacity ∼80 mg g(-1) for both MIPs. Stability and reusability of the MIPs up to the 5th cycle meant that they could be applied repeatedly without losing substantial removal ability. In the next step, the prepared MIP nanoparticles were evaluated as sorbents in a dispersive solid phase extraction (D-SPE) configuration for selective enrichment and determination of metformin and guanylurea in different aqueous matrices. Under the working extraction conditions, the D-SPE method showed good linearity in the range of 50-1000 ng L(-1), repeatability of the extractions (RSD 2.1-5.1%, n=3), and low limits of detection (1.5-3.4 ng L(-1)). The expanded uncertainty of the data obtained was estimated following a bottom-up approach. The proposed method combined the advantages of MIPs and D-SPE, and it could become an alternative tool for analyzing the residues of METF and its transformation product GUA in complex water matrices, such as wastewaters.


Assuntos
Hipoglicemiantes/isolamento & purificação , Metformina/isolamento & purificação , Impressão Molecular , Extração em Fase Sólida , Ureia/isolamento & purificação , Adsorção , Concentração de Íons de Hidrogênio , Hipoglicemiantes/química , Hipoglicemiantes/metabolismo , Metformina/química , Metformina/metabolismo , Nanopartículas/química , Polímeros/química , Temperatura , Termodinâmica , Ureia/análogos & derivados , Águas Residuárias/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
4.
J Chromatogr A ; 1377: 46-54, 2015 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-25543304

RESUMO

In the present report, a simple and cost-effective method for the determination of twelve US EPA priority polycyclic aromatic hydrocarbons (PAHs) in honey samples after salting-assisted liquid-liquid extraction and UHPLC with fluorescence detection is proposed. The sample treatment is based on the usage of hydrophilic acetonitrile as extraction solvent and its phase separation under high salinity conditions. Due to the high sugar content of the samples the phase separation is promoted effortlessly. Several parameters affecting the extraction efficiency and method sensitivity including the concentration of the honey samples, the type and volume of the extraction solvent, the type and quantity of the inorganic salt, extraction time and centrifugation time was systematically investigated. The method was validated in-house according to the Commission Decision 2002/657/EC guidelines. The limit of detection (LOD) of the method lay between 0.02 and 0.04ngmL(-1) (corresponding to 0.08 and 0.16ngg(-1)) which are close to the quality criteria established by European Regulation (EC) 836/2011 concerning the PAHs in foodstuffs. The mean analytical bias (expressed as relative recoveries) in all spiking levels was acceptable being in the range of 54-118% while the relative standard deviation (RSD) was lower than 19%. The proposed method has been satisfactorily applied for the analysis of the selected PAHs residues in various honey samples obtained from Greek region.


Assuntos
Acetonitrilas/química , Técnicas de Química Analítica , Cromatografia Líquida/normas , Tecnologia de Alimentos/métodos , Mel/análise , Extração Líquido-Líquido , Hidrocarbonetos Policíclicos Aromáticos/análise , Cloreto de Sódio/química , Interações Hidrofóbicas e Hidrofílicas , Peso Molecular
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