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1.
J Sep Sci ; 45(18): 3501-3509, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35867888

RESUMO

Herein, for the first time, the wasted cockle shells were modified with nitrogen and sulfur-doped carbon dots after carbonization and used as a suitable bio-based sorbent for the extraction of two important antiemetic drugs named ondansetron and domperidone. The extraction and separation were performed based on vortex-assisted dispersive solid-phase microextraction and high-performance liquid chromatography, respectively. Various techniques such as Fourier-transform infrared, fluorescence, field emission scanning electron microscopy, thermogravimetric analysis, nitrogen adsorption-desorption analysis, X-ray powder diffraction, and energy-dispersive spectroscopy were used to characterize the chemical composition of prepared sorbent. After examining the factors affecting the extraction efficiency and access to the optimal points using the response surface methodology, the linearity was in the range of 5-350 µg/L with acceptable coefficients of determination (R2 > 0.993). The limits of detection and quantification were in the range of 1.5-2.3  and 4.9-7.1 µg/L, respectively. In the end, the proposed method was applied for the quantitative determination of trace levels of target analytes from pharmaceutical tablets, serum, and urine samples. The recoveries were more than 95.2%, indicating the proposed method's excellent accuracy.


Assuntos
Antieméticos , Cardiidae , Microextração em Fase Líquida , Animais , Carbono , Domperidona , Limite de Detecção , Microextração em Fase Líquida/métodos , Nitrogênio , Ondansetron , Preparações Farmacêuticas , Extração em Fase Sólida/métodos , Enxofre
2.
J Sep Sci ; 39(13): 2508-16, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-27136047

RESUMO

In this article, the use of magnetically separable sorbent polyaniline/silica-coated nickel nanoparticles is evaluated under a dispersive micro-solid-phase extraction approach for the extraction of phenolic compounds from water samples. The sorbent was prepared by in situ chemical polymerization of aniline on the surface of silica-modified nickel nanoparticles and was characterized by Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray powder diffraction, scanning electron microscopy, energy-dispersive X-ray spectrometry, and vibrating sample magnetometry. Effective variables such as amount of sorbent (milligrams), pH and ionic strength of sample solution, volume of eluent solvent (microliters), vortex, and ultrasonic times (minutes) were investigated by fractional factorial design. The significant variables optimized by a Box-Behnken design were combined by a desirability function. Under the optimized conditions, the calibration graphs of analytes were linear in a concentration range of 0.02-100 µg/mL, and with correlation coefficients more than 0.999. The limits of detection and quantification were in the ranges of 10-23 and 33-77 µg/L, respectively. This procedure was successfully employed in the determination of target analytes in spiked water samples; the relative mean recoveries ranged from 96 to 105%.

3.
J Sep Sci ; 38(16): 2804-12, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26075653

RESUMO

A selective and sensitive method was developed based on dispersive micro-solid-phase extraction for the extraction of hydroquinone, resorcinol, pyrocatechol and phenol from water samples prior to high-performance liquid chromatography with UV detection. SiO2 , SiO2 @MPTES, and SiO2 @MPTES@Au nanoparticles (MPTES = 3-mercaptopropyltriethoxysilane) were synthesized and characterized by scanning electronic microscopy, thermogravimetric analysis, differential thermogravimetric analysis, and infrared spectroscopy. Variables such as the amount of sorbent (mg), pH and ionic strength of sample the solution, the volume of eluent solvent (µL), vortex and ultrasonic times (min) were investigated by Plackett-Burman design. The significant variables optimized by a Box-Behnken design were combined by a desirability function. Under optimized conditions, the calibration graphs of phenol and dihydroxybenzenes were linear in a concentration range of 1-500 µg/L, and with correlation coefficients more than 0.995. The limits of detection for hydroquinone, resorcinol, pyrocatechol, and phenol were 0.54, 0.58, 0.46, and 1.24 µg/L, and the limits of quantification were 1.81, 1.93, 1.54, and 4.23 µg/L, respectively. This procedure was successfully employed to determine target analytes in spiked water samples; the relative mean recoveries ranged from 93.5 to 98.9%.


Assuntos
Fenol/isolamento & purificação , Fenóis/isolamento & purificação , Dióxido de Silício/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Ouro/química , Limite de Detecção , Fenol/química , Fenóis/química , Extração em Fase Sólida/instrumentação , Poluentes Químicos da Água/química
4.
J Sep Sci ; 38(5): 844-51, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25545187

RESUMO

In the present work, an efficient and environmental friendly method of ionic-liquid-based emulsified microextraction procedure accelerated by ultrasound radiation has been developed. Subsequently, its performance was compared with dispersive liquid-liquid microextraction and ultrasound-assisted surfactant-based emulsification microextraction methods. The optimization of experimental conditions was carried out by combination of central composite design and response surface methodology. The optimum conditions of variables were set as follows: 50 µL of 1-hexyl-3-methylimidazolium hexafluorophosphate (extracting solvent), 10 min ultrasound time, and 10 min vortex time for agitating 6 mL sample solution in pH 3 in the presence of 4 mg sodium dodecyl sulfate without addition of salt and 200 µL of methanol as diluent solvent. Under these conditions, the responses are linear for doxepin and perphenazine in the range of 0.3-1000 and 5-1000 µg/L, respectively. The limits of detection were 0.1 µg/L for doxepin and 1 µg/L for perphenazine. Relative standard deviations were lower than 3.5 for the determination of both species. Finally, the method was used for the preconcentration and determination of doxepin and perphenazine in urine sample with relative recoveries in the range of 89-98%.

5.
J Sep Sci ; 38(14): 2496-502, 2015 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-25989415

RESUMO

In this work, two disperser-free microextraction methods, namely, air-agitated liquid-liquid microextraction and ultrasound-assisted emulsification microextraction are compared for the determination of a number of polycyclic aromatic hydrocarbons in aqueous samples, followed by gas chromatography with flame ionization detection. The effects of various experimental parameters upon the extraction efficiencies of both methods are investigated. Under the optimal conditions, the enrichment factors and limits of detection were found to be in the ranges of 327-773 and 0.015-0.05 ng/mL for air-agitated liquid-liquid microextraction and 406-670 and 0.015-0.05 ng/mL for ultrasound-assisted emulsification microextraction, respectively. The linear dynamic ranges and extraction recoveries were obtained to be in the range of 0.05-120 ng/mL (R(2) ≥ 0.995) and 33-77% for air-agitated liquid-liquid microextraction and 0.05-110 ng/mL (R(2) ≥ 0.994) and 41-67% for ultrasound-assisted emulsification microextraction, respectively. To investigate this common view among some people that smoking hookah is healthy due to the passage of smoke through the hookah water, samples of both the hookah water and hookah smoke were analyzed.

6.
J Sep Sci ; 38(16): 2797-803, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26082081

RESUMO

A molecularly imprinted polymer was selectively applied for solid-phase extraction and diazinon residues enrichment before high-performance liquid chromatography. Diazinon was thermally copolymerized with Fe3 O4 @polyethyleneglycol nanoparticles, methacrylic acid (functional monomer), 2-hydroxyethyl methacrylate (co-monomer), and ethylene glycol dimethacrylate (cross-linking monomer) in the presence of acetonitrile (porogen) and 2,2-azobisisobutyronitrile (initiator). Then, the imprinted diazinon was reproducibly eluted with methanol/acetic acid (9:1, v/v). The sorbent particles were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy. The comprehensive study of variables through experimental design showed that the maximum performance was achieved under these conditions: pH 7, 10 mL sample volume, 15 mg sorbent, 10 min vortex time, 5 min ultrasonic time, 200 µL methanol/acetic acid (9:1, v/v) as eluent, and 5 min desorption time. Under optimized conditions, the molecularly imprinted polymer solid-phase extraction method demonstrated a linear range (0.02-5 g/mL), a correlation coefficient of 0.997, and 0.005 g/mL detection limit.


Assuntos
Diazinon/isolamento & purificação , Polímeros/química , Extração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão , Diazinon/química , Magnetismo , Impressão Molecular , Polímeros/síntese química , Extração em Fase Sólida/instrumentação
7.
RSC Adv ; 13(11): 7664-7672, 2023 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-36908535

RESUMO

The present research aims at reporting a new sorbent, a magnetic nano scale metal-organic framework (MOF), based on nickel acetate and 6-phenyl-1,3,5-triazine-2,4-diamine. The prepared sorbent was used to extract carvacrol and thymol using an ultrasonic-assisted dispersive micro solid phase extraction (UA-DµSPE) method. The structure of the metal organic framework was studied by applying scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectrometry (EDS), and vibrating sample magnetometer (VSM). The effects of various parameters such as ionic strength of sample solution, amount of sorbent (mg), volume of eluent solvent (µL), vortex and ultrasonic times (min) were optimized. Under optimal conditions, the analytes resulted in determination coefficients (R 2) of 0.9985 and 0.9967 in the concentration range 0.01-2 µg mL-1, and in limits of detection of 0.0025 and 0.0028 µg mL-1. Significantly, this method can be successfully applied in order to determine the target analytes in spiked real samples. Notably, the relative mean recoveries range from 94.5 to 105.7%.

8.
J Sep Sci ; 32(4): 511-6, 2009 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-19173322

RESUMO

A simple, sensitive, and inexpensive single drop liquid-liquid-liquid microextraction combined with isocratic RP-HPLC and UV detection was developed for the determination of anti-malaria drug, chloroquine. The target compound was extracted from alkaline aqueous sample solution (adjusted to 0.5 mol/L sodium hydroxide) through a thin layer of organic solvent membrane and back-extracted to an acidic acceptor drop (adjusted to 0.02 mol/L phosphoric acid) suspended on the tip of a 25 microL HPLC syringe in the organic layer. This syringe was also used for direct injection after extraction. The linear range was 1-200 microg/L. The LOD and LOQ were 0.3 and 1.0 microg/L, respectively. Intra-and inter-day precisions were less than 2.0 and 2.3%, respectively. The real samples were successfully analyzed using the proposed method. The recoveries of spiked samples were more than 94.6%.


Assuntos
Antimaláricos/análise , Antimaláricos/química , Cloroquina/análise , Cloroquina/química , Cromatografia Líquida de Alta Pressão , Humanos , Concentração de Íons de Hidrogênio , Solventes , Fatores de Tempo
9.
MethodsX ; 6: 1967-1973, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31667093

RESUMO

Nowadays, antibiotics have been found in the effluents of many pharmaceutical industries and hospitals, sanitary sewage, surface water and groundwater. The purpose of this study was to investigate the possibility of using Hexadecyl Trimethyl Ammonium Bromide modified montmorillonite (HDTMA-Mt) as an inexpensive and suitable adsorbent for the removal of Penicillin G from aqueous solutions. The experiments were conducted in a batch system. The effects of different variables including surfactant loading onto the clay, solution pH, contact time, adsorbate concentration and temperature were investigated on the removal of Penicillin G. Surface properties of the clay were evaluated using X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) techniques. Various isotherms (Langmuir and Freundlich) and kinetics (pseudo-first order, pseudo-second order and intraparticle diffusion models) of adsorption were studied for the data evaluation. The findings indicated that the sorption capacity of the modified clay was found to be 88.5 mg/g over 60 min contact time at pH 9. The pseudo-second kinetic (R2 = 0.999) and Freundlich isotherm (R2 = 0.915) models best fitted the experimental data of Penicillin G by the adsorbent. The negative values of ΔG at higher temperature and positive value of ΔH showed the endothermic and spontaneously sorption of the drug by the clay. It can be concluded that the modified clay can be considered as a cheap and eco-friendly sorbent for the removal of Penicillin G from water and wastewater.

10.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1087-1088: 14-22, 2018 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-29702352

RESUMO

In this work, novel water-dispersible size controlled nanocomposite based on zirconium alkoxide as metal organic precursor was fabricated and subsequently applied for rapid, efficient and selective preconcentration of gallic acid in human plasma and herbal tea samples. The resultant nanocomposite (Fe3O4@Zr(OtBu)4@Laurate) was characterized by Fourier transform infrared, scanning electron microscope and X-ray spectrometer, while laurate forms aggregates on the surface of the nanocomposite and thereby improves sorption of gallic acid. The effects of some variables on efficiency of gallic acid from real samples were optimized by central composite design; while optimum points were achieved as follows: pH 3.5, 35.0 mg of nanocomposite, 150.0 µL of eluent and 3.0 min sonication time. Chromatographic separation was carried out on analytical Nucleosil C18 column (250 × 4.6 mm I.D., 5 µm particle size) at ambient temperature with methanol: water (40:60, v/v) pH adjusted at 3.5 follow by UV detection at 270 nm. Acceptable limit of detection (0.2 µg kg-1) and wide linear range (1.0-700.0 µg kg-1) in coincidence with reasonable enrichment factor (EF = 125) are the unique advantages, which promise this method for quantification of this compound in real samples with complicated matrices.


Assuntos
Ácido Gálico , Nanocompostos/química , Compostos Organometálicos/química , Chás de Ervas/análise , Cromatografia Líquida de Alta Pressão , Análise de Alimentos , Ácido Gálico/análise , Ácido Gálico/sangue , Ácido Gálico/química , Ácido Gálico/isolamento & purificação , Humanos , Limite de Detecção , Modelos Lineares , Tamanho da Partícula , Reprodutibilidade dos Testes
11.
Ultrason Sonochem ; 38: 590-597, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-27562909

RESUMO

Two novel magnetic deep eutectic solvents (MDESs), comprised of cheap and simple components named [choline chloride/phenol] [FeCl4] and [choline chloride/ethylene glycol] [FeCl4] were prepared and characterized by CHN elemental analysis, proton nuclear magnetic resonance (1H NMR), vibrating sample magnetometery (VSM), Raman, Fourier transform-infrared (FT-IR) and UV-Vis spectrometery. The extraction efficiency of the prepared MDESs has been investigated in ultrasound assisted liquid-liquid microextraction based MDES (UALLME-MDES). Briefly, MDESs were added to n-heptan containing thiophene. Then, MDESs were dispersed in n-heptane by sonication. After that, microdroplets of MDESs were collected by a magnet and the remained concentration of thiophene in n-heptane phase was analyzed by GC-FID. The results indicated that [choline chloride/phenol] [FeCl4] has higher extraction efficiency than [choline chloride/ethylene glycol] [FeCl4]. This work opens a new way to the application of MDESs.

12.
Ultrason Sonochem ; 34: 847-855, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27773312

RESUMO

Magnetically separable layered double hydroxide Ni/CuAl-LDH nanocomposites were synthesized and employed as ultrasonic-assisted dispersive micro-solid phase extraction (UA-D-µSPE) sorbent to extract several carboxylic acids (namely propionic, butyric, pentanoic, hexanoic, heptanoic, octanoic, and decanoic) from non-alcoholic beer samples. Ni/CuAl-LDH sorbent was characterized by Fourier transform-infrared (FTIR) spectroscopy, transmission electron microscopy (TEM), and vibrating sample magnetometry (VSM). Effective variables such as amount of sorbent (mg), pH and ionic strength of sample solution, volume of eluent solvent (µL), vortex, and ultrasonic times (min) were investigated via fractional factorial design (FFD). The significant variables were optimized by a Box-Behnken design and combined by a desirability function (DF). Under optimized conditions, the calibration graphs of analytes were linear in a concentration range of 0.05-100µg/mL and had correlation coefficients more than 0.997. The limits of detection and quantification were in the ranges of 16-40µg/L and 53-133µg/L, respectively. This procedure was successfully employed in the determination of target analytes in spiked beer samples, and the relative mean recoveries ranged from 87 to 110%.


Assuntos
Cerveja/análise , Ácidos Carboxílicos/análise , Hidróxidos/química , Metais/química , Nanocompostos/química , Microextração em Fase Sólida/métodos , Ondas Ultrassônicas , Alumínio/química , Ácidos Carboxílicos/isolamento & purificação , Cromatografia Gasosa , Cobre/química , Níquel/química , Solventes/química
13.
Talanta ; 150: 577-85, 2016 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-26838445

RESUMO

A simple, inexpensive and sensitive ultrasonic-assisted liquid-liquid microextraction method based on deep eutectic solvent (UALLME-DES) was used for the extraction of three phenolic acids (ferulic, caffeic and cinnamic) from vegetable oils. In a typical experiment, deep eutectic solvent as green extraction solvent was added to n-hexane (as a typical oil medium) containing target analytes. Subsequently, the extraction was accelerated by sonication. After the extraction, phase separation (DES rich phase/n-hexane phase) was performed by centrifugation. DES rich phase (lower phase) was withdrawn by a micro-syringe and submitted to isocratic reverse-phase HPLC with UV detection. Under optimum conditions obtained by response surface methodology (RSM) and desirability function (DF), the method has good linear calibration ranges (between 1.30 and 1000 µg L(-1)), coefficients of determination (r(2)>0.9949) and low limits of detection (between 0.39 and 0.63 µg L(-1)). This procedure was successfully applied to the determination of target analytes in olive, almond, sesame and cinnamon oil samples. The relative mean recoveries ranged from 94.7% to 104.6%.


Assuntos
Ácidos Cafeicos/análise , Cromatografia Líquida de Alta Pressão/métodos , Cinamatos/análise , Ácidos Cumáricos/análise , Microextração em Fase Líquida/métodos , Solventes/química , Ultrassom , Cinnamomum zeylanicum/química , Humanos , Olea/química , Óleos de Plantas/química , Prunus dulcis/química , Sesamum/química , Espectrofotometria Ultravioleta/métodos
14.
Ultrason Sonochem ; 32: 380-386, 2016 09.
Artigo em Inglês | MEDLINE | ID: mdl-27150784

RESUMO

A two-step sample preparation technique based on dispersive micro solid-phase extraction combined with coacervative microextraction is presented for preconcentration and determination of tricyclic antidepressant drugs in biological samples. An important feature of the method is the application of hydrophobic magnetic nanoparticles, which in combination with coacervative microextraction method enables development of rapid and efficient extraction procedure in order to achievement of a high extraction efficiency. Simultaneous optimization by experimental design lead to improvement of method with low cost which supply useful information about interaction among variables. Under the optimized conditions, a linear range of 5-1000ngmL(-1) with detection limits from 0.51 to 1.4ngmL(-1) were obtained for target analytes. The method was successfully used for the determination of analytes in biological fluids (plasma and urine) with relative recoveries in the range of 89-105% (RSDs<3.5%).


Assuntos
Antidepressivos Tricíclicos/análise , Nanopartículas de Magnetita/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Magnetismo , Extração em Fase Sólida
15.
J Chromatogr A ; 1425: 25-33, 2015 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-26614169

RESUMO

In this study, for the first time, a simple, inexpensive and sensitive method named emulsification liquid-liquid microextraction based on deep eutectic solvent (ELLME-DES) was used for the extraction of benzene, toluene, ethylbenzene (BTE) and seven polycyclic aromatic hydrocarbons (PAHs) from water samples. In a typical experiment, 100µL of DES (as water-miscible extraction solvent) was added to 1.5mL of sample solution containing target analytes. A homogeneous solution was formed immediately. Injection of 100µL of THF (as emulsifier agent) into homogeneous solution provided a turbid state. After extraction, phase separation (aqueous phase/DES rich phase) was performed by centrifugation. DES rich phase was withdrawn by a micro-syringe and submitted to isocratic reverse-phase HPLC with UV detection. Under optimum conditions obtained by response surface methodology (RSM) and desirability function (DF), the calibration graphs were linear in the concentration range from 10 to 200µg/L for benzene, 10-400µg/L for toluene, 1-400µg/L for ethylbenzene, biphenyl, chrysene and fluorene, and 0.1-400µg/L for anthracene, benzo[a]pyrene, phenanthrene and pyrene. The coefficients of determination (r(2)) and limits of detection were 0.9924-0.9997 and 0.02-6.8µg/L, respectively. This procedure was successfully applied to the determination of target analytes in spiked water samples. The relative mean recoveries ranged from 93.1 to 103.3%.


Assuntos
Derivados de Benzeno/análise , Benzeno/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Tolueno/análise , Poluentes Químicos da Água/análise , Calibragem , Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Líquida/métodos , Solventes , Água/química
16.
J Chromatogr Sci ; 53(7): 1222-31, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25637132

RESUMO

A novel vortex-assisted surfactant-enhanced dispersive liquid-liquid microextraction combined with high-performance liquid chromatography (VASEDLLME-HPLC) was developed for the determination of thymol and carvacrol (phenolic compound). In this method, the extraction solvent (CHCl3) was dispersed into the aqueous samples via a vortex agitator and addition of the surfactant (Triton X-100). The preliminary experiments were undertaken to select the best extraction solvent and surfactant. The influences of effective variables were investigated using a Plackett-Burman 2(7-4) screening design and then, the significant variables were optimized by using a central composite design combined with desirability function. Working under optimum conditions specified as: 140 µL CHCl3, 0.08% (w/v, Triton X-100), 3 min extraction time, 6 min centrifugation at 4,500 rpm, pH 7, 0.0% (w/v) NaCl permit achievement of high and reasonable linear range over 0.005-4.0 mg L(-1) with R(2) = 0.9998 (n = 10). The separation of thymol and carvacrol was achieved in <14 min using a C18 column and an isocratic binary mobile phase acetonitrile-water (55:45, v/v) with a flow rate of 1.0 mL min(-1). The VASEDLLME is applied for successful determination of carvacrol and thymol in different thyme and pharmaceutical samples with relative standard deviation <4.7% (n = 5).


Assuntos
Anti-Infecciosos/análise , Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Líquida/métodos , Monoterpenos/análise , Timol/análise , Cromatografia Líquida de Alta Pressão/instrumentação , Cimenos , Desenho de Equipamento , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Octoxinol/química , Tensoativos/química
17.
Artigo em Inglês | MEDLINE | ID: mdl-25484348

RESUMO

In the present study, for the first time, a new extraction method based on "ultrasound assisted microextraction-nanomaterial solid phase dispersion (UAME-NMSPD)" was developed to preconcentrate the low quantity of thymol and carvacrol in pharmaceutical samples prior to their HPLC-UV separation/determination. The analytes were accumulated on nickel sulfide nanomaterial loaded on activated carbon (NiS-NP-AC) that with more detail identified by XRD, FESEM and UV-vis technique. Central composite design (CCD) combined with desirability function (DF) was used to search for optimum operational conditions. Working under optimum conditions specified as: 10 min ultrasonic time, pH 3, 0.011 g of adsorbent and 600 µL extraction solvent) permit achievement of high and reasonable linear range over 0.005-2.0 µg mL(-1) (r(2)>0.9993) with LOD of thymol and carvacrol as 0.23 and 0.21 µg L(-1), respectively. The relative standard deviations (RSDs) were less than 4.93% (n=3).


Assuntos
Anti-Infecciosos/isolamento & purificação , Monoterpenos/isolamento & purificação , Microextração em Fase Sólida/instrumentação , Timol/isolamento & purificação , Ultrassom/instrumentação , Carvão Vegetal/química , Cromatografia Líquida de Alta Pressão , Cimenos , Desenho de Equipamento , Nanoestruturas/química , Níquel/química , Preparações Farmacêuticas/química
18.
Environ Toxicol Chem ; 33(12): 2694-701, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25242239

RESUMO

A simple and low-cost method that indirectly suspended droplet microextraction of water-miscible organic solvents (ISDME) by salting-out effect before high-performance liquid chromatography and ultraviolet (HPLC-UV) detection was used for the determination of polycyclic aromatic hydrocarbons (PAHs) in different samples. The ISDME is a combination of salting-out extraction of water-miscible organic solvent and directly suspended droplet microextraction (DSDME). Ninety-five microliters water-miscible organic solvent (1-propanol) was added to a 500-µL sample. A homogeneous solution was formed immediately. To produce a steady vortex at the top of the solution, the sample was agitated at 700 rpm using a magnetic stirrer. By the addition of ammonium sulfate (saturated solution) to the homogeneous solution, 1-propanol was separated and collected at the bottom of the steady vortex. Finally, 20 µL 1-propanol was injected into HPLC-UV. The effects of important parameters such as water-miscible organic solvent (type and volume), type of salt, and extraction time were evaluated. Under optimum conditions, the method has a good linear calibration range (0.1 µg/L-300 µg/L), coefficients of determination (R(2) > 0.998), low limits of detection (between 0.02 µg/L and 0.27 µg/L), and acceptable recovery (>85.0%).


Assuntos
Hidrocarbonetos Policíclicos Aromáticos/análise , Solventes/química , Espectrofotometria Ultravioleta , 1-Propanol/química , Sulfato de Amônio/química , Calibragem , Cromatografia Líquida de Alta Pressão , Frutas/química , Microextração em Fase Líquida , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/normas , Espectrofotometria Ultravioleta/normas , Verduras/química , Água/química , Poluentes Químicos da Água/análise
19.
Food Chem ; 161: 120-6, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24837929

RESUMO

A novel approach, ultrasound-assisted reverse micelles dispersive liquid-liquid microextraction (USA-RM-DLLME) followed by high performance liquid chromatography (HPLC) was developed for selective determination of acetoin in butter. The melted butter sample was diluted and homogenised by n-hexane and Triton X-100, respectively. Subsequently, 400µL of distilled water was added and the microextraction was accelerated by 4min sonication. After 8.5min of centrifugation, sedimented phase (surfactant-rich phase) was withdrawn by microsyringe and injected into the HPLC system for analysis. The influence of effective variables was optimised using Box-Behnken design (BBD) combined with desirability function (DF). Under optimised experimental conditions, the calibration graph was linear over the range of 0.6-200mgL(-1). The detection limit of method was 0.2mgL(-1) and coefficient of determination was 0.9992. The relative standard deviations (RSDs) were less than 5% (n=5) while the recoveries were in the range of 93.9-107.8%.


Assuntos
Acetoína/química , Manteiga/análise , Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Líquida/métodos , Micelas , Ultrassom
20.
Hum Exp Toxicol ; 33(8): 863-72, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24275645

RESUMO

Aminophenol isomers (2-, 3-, and 4-aminophenols) are typically classified as industrial pollutants with genotoxic and mutagenic effects due to their easy penetration through the skin and membranes of human, animals, and plants. In the present study, a simple and efficient ultrasound-assisted emulsification microextraction procedure coupled with high-performance liquid chromatography with ultraviolet detector was developed for preconcentration and determination of these compounds in human fluid and environmental water samples. Effective parameters (such as type and volume of extraction solvent, pH and ionic strength of sample, and ultrasonication and centrifuging time) were investigated and optimized. Under optimum conditions (including sample volume: 5 mL; extraction solvent: chloroform, 80 µL; pH: 6.5; without salt addition; ultrasonication: 3.5 min; and centrifuging time: 3 min, 5000 rpm min(-1)), the enrichment factors and limits of detection were ranged from 42 to 51 and 0.028 to 0.112 µg mL(-1), respectively. Once optimized, analytical performance of the method was studied in terms of linearity (0.085-157 µg mL(-1), r (2) > 0.998), accuracy (recovery = 88.6- 101.7%), and precision (repeatability: intraday precision < 3.98%, and interday precision < 5.12%). Finally, applicability of the method was evaluated by the extraction and determination of these compounds in human urine, hair dye, and real water samples.


Assuntos
Aminofenóis/análise , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental/métodos , Tinturas para Cabelo/química , Microextração em Fase Líquida/métodos , Ultrassom/métodos , Poluentes Químicos da Água/análise , Aminofenóis/urina , Centrifugação , Clorofórmio/química , Cromatografia Líquida de Alta Pressão/normas , Monitoramento Ambiental/normas , Humanos , Concentração de Íons de Hidrogênio , Isomerismo , Limite de Detecção , Modelos Lineares , Microextração em Fase Líquida/normas , Concentração Osmolar , Reprodutibilidade dos Testes , Cloreto de Sódio/química , Solventes/química , Sonicação , Espectrofotometria Ultravioleta , Fatores de Tempo , Ultrassom/normas , Poluentes Químicos da Água/urina
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