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1.
Curr Top Med Chem ; 2024 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-38867521

RESUMO

Osteoarthritis (OA) is a common chronic articular degenerative disease characterized by articular cartilage degradation, synovial inflammation/immunity, and subchondral bone lesions. Recently, increasing interest has been devoted to treating or preventing OA with herbal medicines. The mechanism of action of plant raw materials used in osteoarthrosis treatment is well documented. They are sought after because of the high frequency of inflammation of the knee joint among both elderly and young people engaged in sports in which their knee joints are often exposed to high-stress conditions. The purpose of this work was to present some most effective and safe plant medicines with proven mechanisms of action that can help to alleviate the growing social problem of osteoarthrosis caused in recent years. A review of the available literature based primarily on the latest editions of ESCOP and EMA monographs and the latest scientific papers has made it possible to select and propose medical management of osteoarthrosis by ranking plant medicines according to their effectiveness. Clinical studies of raw plant materials, such as Harpagophyti radix, Olibanum indicum, and Urticae foliumet herba have indicated that these drugs should be considered the first choice in osteoarthrosis treatment. The efficacy of Rosae pseudo-fructus, Salicis cortex, Filipendulae ulmariae flos et herba, Ribis nigri folium, and externally applied Capsici fructus and Symphyti radix, has also been proven by pharmacological studies. All the plant medicines mentioned in the paper have been studied in detail in terms of their phytochemistry, which can help doctors in their decision-- making in the treatment of osteoarthrosis.

2.
Molecules ; 28(10)2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37241881

RESUMO

A dispersive micro-solid phase extraction (Dµ-SPE) method for the preconcentration of trace metal ions (Pb, Cd, Cr, Mn, Fe, Co, Ni, Cu, Zn) on graphene oxide with the complexing reagents neocuproine or batocuproine is presented here. Metal ions form cationic complexes with neocuproine and batocuproine. These compounds are adsorbed on the GO surface via electrostatic interactions. The factors affecting the separation and preconcentration of analytes such as pH, eluent (concentration, type, volume), amount of neocuproine, batocuproine and GO, mixing time, and sample volume were optimized. The optimal sorption pH was 8. The adsorbed ions were effectively eluted with 5 mL 0.5 mol L-1 HNO3 solution and determined by the ICP-OES technique. The preconcentration factor for the GO/neocuproine and GO/batocuproine in the range 10-100 and 40-200 was obtained for the analytes, with detection limits of 0.035-0.84 ng mL-1 and 0.047-0.54 ng mL-1, respectively. The method was validated by the analysis of the three certified reference materials: M-3 HerTis, M-4 CormTis, and M-5 CodTis. The procedure was applied to determine metal levels in food samples.


Assuntos
Metais , Extração em Fase Sólida , Extração em Fase Sólida/métodos , Indicadores e Reagentes , Íons
3.
Mikrochim Acta ; 186(2): 91, 2019 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-30631926

RESUMO

Graphene oxide (GO) was chemically functionalized with 5-amino-1,10-phenanthroline. The resulting conjugate (phen-GO) was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. The experiments show that phen-GO has a high affinity for extraction of Pb(II) ions. Isotherms and kinetics fit the Langmuir model and pseudo-second-order equations. By using phen-GO as a sorbent, Pb(II) ions can be quantitatively adsorbed at pH 6.0. The adsorption capacity is 548 mg g-1. Following desorption with 2 mol L-1 HNO3, Pb(II) was quantified by inductively coupled plasma optical emission spectrometry. The effects of pH value, eluent type, sorption time, sample volume, and matrix ions were optimized. The accuracy of the method was validated by analysis of the reference materials DOLT-3 (dogfish liver) and SRM 1640a (natural water). Under optimal conditions, the calibration plots cover the 0.25 to 500 ng mL-1 Pb(II) concentration range. The method was successfully applied to the analysis of spiked water and biological samples. Other figures of merit include a preconcentration factor of 250, a detection limit of 46 ng L-1, and a relative standard deviation of <5%. Graphical abstract Schematic presentation of the dispersive solid-phase extraction of lead(II) ions using graphene oxide modified with 5-amino-1,10-phenanthroline, followed by their determination by inductively coupled plasma optical emission spectrometry (ICP OES).

4.
Food Chem ; 249: 38-44, 2018 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-29407929

RESUMO

Among cereals, rice is the second most cultivated staple crop in the world. It may be contaminated by toxic heavy metals present in water or soil. Therefore, monitoring the presence of heavy metals in rice and its products is a matter of a great importance from the nutritional and toxicological view. In this paper, a simple and effective analytical procedure based on dispersive micro solid-phase extraction with the use of oxidized multiwalled carbon nanotubes and batophenanthroline was developed for the determination of lead, cadmium, zinc, manganese and iron in white and wild rice samples. Due to the high preconcentration factor of 200, the optimized procedure allows obtaining detection limits between 0.13 and 0.35 ng mL-1 using flame atomic absorption spectrometry (FAAS). Novel preconcentration method can successfully be applied in food analysis with accuracy better than 7% rel. and repeatability lower than 3%.


Assuntos
Quelantes/química , Complexos de Coordenação/análise , Contaminação de Alimentos/análise , Metais Pesados/análise , Nanotubos de Carbono/química , Oryza/química , Fenantrolinas/química , Cátions , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Limite de Detecção , Extração em Fase Sólida/instrumentação , Extração em Fase Sólida/métodos , Espectrofotometria Atômica/métodos
5.
Food Chem ; 209: 37-42, 2016 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-27173531

RESUMO

A dispersive micro solid phase extraction (DMSPE) method for the selective preconcentration of trace lead ions on oxidized multiwalled carbon nanotubes (ox-MWCNTs) with complexing reagent 1,10-phenanthroline is presented. Flame and electrothermal atomic absorption spectrometry (F-AAS, ET-AAS) were used for detection. The influence of several parameters such as pH, amount of sorbent and 1,10-phenanthroline, stirring time, concentration and volume of eluent, sample flow rate and sample volume was examined using batch procedures. Moreover, effects of inorganic matrix on recovery of the determined elements were studied. The experiment shows that foreign ions did not influence on recovery of the determined element. The method characterized by high selectivity toward Pb(II) ions. Lead ions can be quantitatively retained at pH 7 from sample volume up to 400mL and then eluent completely with 2mL of 0.5molL(-1)HNO3. The detection limits of Pb was 0.26µgL(-1) for F-AAS and 6.4ngL(-1) for ET-AAS. The recovery of the method for the determined lead was better than 97% with relative standard deviation lower than 3.0%. The preconcentration factor was 200 for F-AAS and 100 for ET-AAS. The maximum adsorption capacity of the adsorbent was found to be about 350mgg(-1). The method was applied for determination of Pb in fish samples with good results. Accuracy of the method was verified using certified reference material DOLT-3 and ERM-BB186.


Assuntos
Chumbo/análise , Chumbo/isolamento & purificação , Nanotubos de Carbono/química , Fenantrolinas/química , Extração em Fase Sólida/métodos , Adsorção , Oxirredução , Espectrofotometria Atômica/métodos
6.
ACS Appl Mater Interfaces ; 6(22): 20144-53, 2014 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-25329565

RESUMO

The aminosilanized graphene oxide (GO-NH2) was prepared for selective adsorption of Pb(II) ions. Graphene oxide (GO) and GO-NH2 prepared through the amino-silanization of GO with 3-aminopropyltriethoxysilane were characterized by scanning electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy, and Raman spectroscopy. The batch experiments show that GO-NH2 is characterized by high selectivity toward Pb(II) ions. Adsorption isotherms suggest that sorption of Pb(II) on GO-NH2 nanosheets is monolayer coverage, and adsorption is controlled by a chemical process involving the surface complexation of Pb(II) ions with the nitrogen-containing groups on the surface of GO-NH2. Pb(II) ions can be quantitatively adsorbed at pH 6 with maximum adsorption capacity of 96 mg g(-1). The GO-NH2 was used for selective and sensitive determination of Pb(II) ions by electrothermal atomic absorption spectrometry (ET-AAS). The preconcentration of Pb(II) ions is based on dispersive micro solid-phase extraction in which the suspended GO-NH2 is rapidly injected into analyzed water sample. Such features of GO-NH2 nanosheets as wrinkled structure, softness, flexibility, and excellent dispersibility in water allow achieving very good contact with analyzed solution, and adsorption of Pb(II) ions is very fast. The experiment shows that after separation of the solid phase, the suspension of GO-NH2 with adsorbed Pb(II) ions can be directly injected into the graphite tube and analyzed by ET-AAS. The GO-NH2 is characterized by high selectivity toward Pb(II) ions and can be successfully used for analysis of various water samples with excellent enrichment factors of 100 and detection limits of 9.4 ng L(-1).

7.
Anal Chim Acta ; 834: 22-9, 2014 Jun 27.
Artigo em Inglês | MEDLINE | ID: mdl-24928241

RESUMO

Graphene oxide (GO) is a novel material with excellent adsorptive properties. However, the very small particles of GO can cause serious problems is solid-phase extraction (SPE) such as the high pressure in SPE system and the adsorbent loss through pores of frit. These problems can be overcome by covalently binding GO nanosheets to a support. In this paper, GO was covalently bonded to spherical silica by coupling the amino groups of spherical aminosilica and the carboxyl groups of GO (GO@SiO2). The successful immobilization of GO nanosheets on the aminosilica was confirmed by scanning electron microscopy and X-ray photoelectron spectroscopy. The spherical particle covered by GO with crumpled silk wave-like carbon sheets are an ideal sorbent for SPE of metal ions. The wrinkled structure of the coating results in large surface area and a high extractive capacity. The adsorption bath experiment shows that Cu(II) and Pb(II) can be quantitatively adsorbed at pH 5.5 with maximum adsorption capacity of 6.0 and 13.6 mg g(-1), respectively. Such features of GO nanosheets as softness and flexibility allow achieving excellent contact with analyzed solution in flow-rate conditions. In consequence, the metal ions can be quantitatively preconcentrated from high volume of aqueous samples with excellent flow-rate. SPE column is very stable and several adsorption-elution cycles can be performed without any loss of adsorptive properties. The GO@SiO2 was used for analysis of various water samples by flame atomic absorption spectrometry with excellent enrichment factors (200-250) and detection limits (0.084 and 0.27 ng mL(-1) for Cu(II) and Pb(II), respectively).

8.
Food Chem ; 147: 225-9, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24206710

RESUMO

A method of separation and preconcentration of cadmium, copper, nickel, lead and zinc at trace level using 8-hydroxyquinoline as a chelating agent and lanthanum(III) as a carrier element is proposed. The heavy metals were determined after preconcentration by inductively coupled plasma optical emission spectrometry (ICP-OES). The results were compared with those obtained using flame atomic absorption spectrometry (F-AAS). The influence of several parameters such as pH, amount of lanthanum(III) as a carrier element, amount of 8-hydroxyquinoline, duration of co-precipitation was examined. Moreover, effects of inorganic matrix on recovery of the determined elements were studied. The detection limits (DL) for ICP-OES were 0.31, 2.9, 1.4, 3.2 and 1.2 µg L(-1) for Cd, Cu, Ni, Pb and Zn, respectively, whereas for F-AAS DL were 0.63, 1.1, 3.2, 2.7 and 0.74 µg L(-1). The recovery of the method for the determined elements was better than 94% with relative standard deviation between 0.63% and 2.9%. The preconcentration factor was 60. The proposed method was successfully applied for determination of Cd, Cu, Ni, Pb, and Zn in plant materials. Accuracy of the proposed method was verified using certified reference material (NCS ZC85006 Tomato).


Assuntos
Técnicas de Química Analítica/métodos , Lantânio/química , Metais/química , Oxiquinolina/química , Precipitação Química , Espectrofotometria Atômica
9.
Food Chem ; 147: 302-6, 2014 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-24206722

RESUMO

A method of separation and preconcentration of cadmium, cobalt, copper, nickel, lead, and zinc at trace level using activated carbon is proposed. Activated carbon with the adsorbed trace metals was mineralised using a high-pressure microwave mineraliser. The heavy metals were determined after preconcentration by inductively coupled plasma optical emission spectrometry (ICP-OES). The influence of several parameters, such as pH, sorbent mass, shaking time was examined. Moreover, effects of inorganic matrix on recovery of the determined elements were studied. The experiment shows that foreign ions did not influence recovery of the determined elements. The detection limits (DL) of Cd, Co, Cu, Ni, Pb, and Zn were 0.17, 0.19, 1.60, 2.60, 0.92 and 1.50 µg L(-)(1), respectively. The recovery of the method for the determined elements was better than 95% with relative standard deviation from 1.3% to 3.7%. The preconcentration factor was 80. The proposed method was applied for determination of Cd, Co, Cu, Ni, Pb, and Zn in fruits materials. Accuracy of the proposed method was verified using certified reference material (NCS ZC85006 Tomato).


Assuntos
Frutas/química , Espectrometria de Massas/métodos , Metais Pesados/química , Solanum lycopersicum/química , Extração em Fase Sólida/métodos , Adsorção , Carvão Vegetal/química , Contaminação de Alimentos/análise , Limite de Detecção , Metais Pesados/isolamento & purificação , Extração em Fase Sólida/instrumentação
10.
Dalton Trans ; 42(16): 5682-9, 2013 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-23443993

RESUMO

The adsorptive properties of graphene oxide (GO) towards divalent metal ions (copper, zinc, cadmium and lead) were investigated. GO prepared through the oxidation of graphite using potassium dichromate was characterized by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (FT-IR). The results of batch experiments and measurements by flame atomic absorption spectrometry (F-AAS) indicate that maximum adsorption can be achieved in broad pH ranges: 3-7 for Cu(II), 5-8 for Zn(II), 4-8 for Cd(II), 3-7 for Pb(II). The maximum adsorption capacities of Cu(II), Zn(II), Cd(II) and Pb(II) on GO at pH = 5 are 294, 345, 530, 1119 mg g(-1), respectively. The competitive adsorption experiments showed the affinity in the order of Pb(II) > Cu(II) ≫ Cd(II) > Zn(II). Adsorption isotherms and kinetic studies suggest that sorption of metal ions on GO nanosheets is monolayer coverage and adsorption is controlled by chemical adsorption involving the strong surface complexation of metal ions with the oxygen-containing groups on the surface of GO. Chemisorption was confirmed by XPS (binding energy and shape of O1s and C1s peaks) of GO with adsorbed metal ions. The adsorption experiments show that the dispersibility of GO in water changes remarkably after complexation of metal ions. After adsorption, the tendency to agglomerate and precipitate is observed. Excellent dispersibility of GO and strong tendency of GO-Me(II) to precipitate open the path to removal of heavy metals from water solution. Potential application of GO in analytical chemistry as a solid sorbent for preconcentration of trace elements and in heavy metal ion pollution cleanup results from its maximum adsorption capacities that are much higher than those of any of the currently reported sorbents.

11.
Talanta ; 88: 391-5, 2012 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-22265515

RESUMO

A method of separation and preconcentration of cadmium, cobalt, copper, nickel, lead and zinc at trace level from plant matrix using 2,2'-bipyridyl and rose Bengal is proposed. The above heavy metals were determined after preconcentration by inductively coupled plasma optical emission spectrometry (ICP-OES). The results were compared with those obtained using flame atomic absorption spectrometry (F-AAS). The influence of several parameters such as pH, molar ratio of 2,2'-bipyridyl to rose Bengal, duration of co-precipitation was examined. Moreover, effects of inorganic matrix on recovery of the determined elements were studied. The detection limits (DL) for ICP-OES were 0.36, 0.66, 3.3, 1.4, 3.5 and 3.2 µgL(-1) for Cd, Co, Cu, Ni, Pb and Zn, respectively, whereas for F-AAS DL were 0.77, 5.8, 1.1, 3.2, 3.0 and 0.71 µgL(-1). The recovery of the method for the determined elements was better than 94% with relative standard deviation between 0.68% and 1.7%. The preconcentration factor was 40. The proposed method was applied for determination of Cd, Co, Cu, Ni, Pb, and Zn in plant materials. Accuracy of the proposed method was verified using certified reference material (NCS ZC85006 Tomato).


Assuntos
Brassica/química , Metais Pesados/análise , Solanum tuberosum/química , 2,2'-Dipiridil/química , Fracionamento Químico , Ionização de Chama , Concentração de Íons de Hidrogênio , Indicadores e Reagentes/química , Limite de Detecção , Padrões de Referência , Rosa Bengala/química , Espectrofotometria Atômica
12.
J Hazard Mater ; 152(3): 1122-9, 2008 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-17850961

RESUMO

The applicability of 2,2'-bipyridyl and erythrosine co-precipitation method for the separation and preconcentration of some heavy metals, such as Cd, Co, Cu, Ni, Pb and Zn in actual samples for their determination by ICP-OES and F-AAS was studied. Experimental conditions influencing the recovery of the investigated metals, such as pH, molar ratio of 2,2'-bipyridyl to erythrosine, the effect of time on co-precipitation were optimized. The analytical characteristics of the method (e.g. limit of detection, sensitivity, linear range and preconcentration factor) were obtained. The limits of detection LOD (ng mL(-1)) of the ICP-OES (F-AAS) method were: Cd: 4.0 (7.75), Co: 3.1 (57.2), Cu: 18 (10.3), Ni 21.3 (32.8), Pb: 35.9 (29.2) and Zn: 10.2 (6.90). The recovery of all the elements tested was more than 93%. The influence of inorganic matrix was examined. The proposed method was applied to determination of Cd, Co, Cu, Ni, Pb and Zn in vegetables and certified reference material (NCS ZC85006 Tomato).


Assuntos
2,2'-Dipiridil/química , Eritrosina/química , Metais Pesados/análise , Espectrofotometria Atômica/métodos , Calibragem , Precipitação Química , Padrões de Referência , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
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