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1.
Molecules ; 26(12)2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34205651

RESUMO

High-pressure processing (HPP) has emerged over the last 2 decades as a good alternative to traditional thermal treatment for food safety and shelf-life extension, supplying foods with similar characteristics to those of fresh products. Currently, HPP has also been proposed as a useful tool to reduce food contaminants, such as pesticides and mycotoxins. The aim of the present study is to explore the effect of HPP technology at 600 MPa during 5 min at room temperature on alternariol (AOH) and aflatoxin B1 (AFB1) mycotoxins reduction in different juice models. The effect of HPP has also been compared with a thermal treatment performed at 90 °C during 21 s. For this, different juice models, orange juice/milk beverage, strawberry juice/milk beverage and grape juice, were prepared and spiked individually with AOH and AFB1 at a concentration of 100 µg/L. After HPP and thermal treatments, mycotoxins were extracted from treated samples and controls by dispersive liquid-liquid microextraction (DLLME) and determined by HPLC-MS/MS-IT. The results obtained revealed reduction percentages up to 24% for AFB1 and 37% for AOH. Comparing between different juice models, significant differences were observed for AFB1 residues in orange juice/milk versus strawberry juice/milk beverages after HPP treatment. Moreover, HPP resulted as more effective than thermal treatment, being an effective tool to incorporate to food industry in order to reach mycotoxins reductions.


Assuntos
Aflatoxinas/química , Bebidas/análise , Sucos de Frutas e Vegetais/análise , Frutas/química , Leite/química , Vitis/química , Animais , Cromatografia Líquida de Alta Pressão/métodos , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Lactonas/química , Microextração em Fase Líquida/métodos , Micotoxinas/química , Espectrometria de Massas em Tandem/métodos
2.
Molecules ; 26(11)2021 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-34067333

RESUMO

This work entailed the development, optimization, validation, and application of a novel analytical approach, using the bar adsorptive microextraction technique (BAµE), for the determination of the six most common tricyclic antidepressants (TCAs; amitriptyline, mianserin, trimipramine, imipramine, mirtazapine and dosulepin) in urine matrices. To achieve this goal, we employed, for the first time, new generation microextraction devices coated with convenient sorbent phases, polymers and novel activated carbons prepared from biomaterial waste, in combination with large-volume-injection gas chromatography-mass spectrometry operating in selected-ion monitoring mode (LVI-GC-MS(SIM)). Preliminary assays on sorbent coatings, showed that the polymeric phases present a much more effective performance, as the tested biosorbents exhibited low efficiency for application in microextraction techniques. By using BAµE coated with C18 polymer, under optimized experimental conditions, the detection limits achieved for the six TCAs ranged from 0.2 to 1.6 µg L-1 and, weighted linear regressions resulted in remarkable linearity (r2 > 0.9960) between 10.0 and 1000.0 µg L-1. The developed analytical methodology (BAµE(C18)/LVI-GC-MS(SIM)) provided suitable matrix effects (90.2-112.9%, RSD ≤ 13.9%), high recovery yields (92.3-111.5%, RSD ≤ 12.3%) and a remarkable overall process efficiency (ranging from 84.9% to 124.3%, RSD ≤ 13.9%). The developed and validated methodology was successfully applied for screening the six TCAs in real urine matrices. The proposed analytical methodology proved to be an eco-user-friendly approach to monitor trace levels of TCAs in complex urine matrices and an outstanding analytical alternative in comparison with other microextraction-based techniques.


Assuntos
Antidepressivos Tricíclicos/urina , Microextração em Fase Sólida/métodos , Urinálise/métodos , Adsorção , Materiais Biocompatíveis/química , Carvão Vegetal/química , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Concentração de Íons de Hidrogênio , Íons , Limite de Detecção , Microextração em Fase Líquida/métodos , Polímeros/química , Polipropilenos/química , Reprodutibilidade dos Testes , Urinálise/normas , Água/química
3.
J Chromatogr A ; 1651: 462330, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34161833

RESUMO

A new automated micro liquid-liquid extraction technique was successfully developed. This novel syringe-based technique capitalizes on the advantages of vigorous fluid agitation and the shearing effect of two fluids with different properties to achieve high extraction efficiency. The technique is at least 20 times faster than mechanical shaking or sonication in achieving a similar recovery even with a hydrophilic probe molecule such as 1,4-dioxane in an aqueous medium. Excellent repeatability with a relative standard deviation as low as 0.56% over a five-day test, n = 2 per day, was demonstrated with 1,4-dioxane. Other model compounds in aqueous matrices evaluated, including phenolics and extraction solvents like chloroform and hexane, showed similar performance in repeatability. An added advantage of this technique involves performing multiple extractions. Its capabilities in conducting complicated extraction steps and minimizing the use of organic solvents as low as 200 µL to achieve a preconcentration effect were demonstrated. The technique is suitable for use with emulsion-forming samples without further sample manipulation by incorporating a demulsifier such as acetone during the extraction process. The technique was found to be efficient and environmentally friendly with low solvent waste. This technique is ideal for implementation in automated high throughput and cost-effective quality assurance laboratory environments.


Assuntos
Microextração em Fase Líquida/métodos , Automação , Emulsões , Microextração em Fase Líquida/tendências , Solventes/química , Água/química
4.
Food Chem ; 361: 130097, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34029900

RESUMO

A new, green, and simple liquid-phase microextraction method namely sieve conducted two syringe-based pressurized liquid-phase microextraction methods was combined with flame atomic absorption spectrometry for the preconcentration and determination of cobalt. For this aim, a novel automated syringe mixing system was developed to be used in the developed extraction procedure. Two syringes were connected to each other by an apparatus having six holes to produce efficient dispersion of the extractant. The pressure created between the two syringes by the forward and backward movements of the syringe plungers created an efficient dispersion of the extractant. In the present study, ligand as complexing agent was synthesized in our laboratory. Limits of detection and quantification were determined to be 1.8 and 6.0 µg L-1, respectively. A 33.7-fold enhancement in detection power was obtained with the developed method. Method was effectively applied for the determination of cobalt in quince samples.


Assuntos
Cobalto/análise , Cobalto/isolamento & purificação , Microextração em Fase Líquida/métodos , Rosaceae/química , Espectrofotometria Atômica , Automação , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Seringas
5.
Food Chem ; 358: 129857, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33940293

RESUMO

In this study, a sensitive, selective, and environmentally friendly analytical method for direct extraction and preconcentration of iodine was developed. Iodine, as an iodate ion or iodide ion, was simultaneously extracted and preconcentrated by gel electromembrane microextraction (G-EME) and analyzed for total iodine by ion chromatography. The total iodine was determined by combining the peak areas of both iodate and iodide ions. Under the optimized conditions, linear calibration for iodine using a mixture of iodate and iodide ions was obtained from 10 to 100 µg L-1 (r2 > 0.996). The detection limit was 7.0 µg L-1. Recoveries of spiked iodine (as iodate) in the samples were greater than 90%. The method was applied for the determination of iodine in dietary supplements and fortified food samples, i.e., iodine-enriched eggs. Our developed method could be directly applied for the determination of iodine in different matrix samples including eggs without a pretreatment step.


Assuntos
Cromatografia/métodos , Suplementos Nutricionais/análise , Análise de Alimentos/métodos , Alimentos Fortificados/análise , Iodo/análise , Calibragem , Cromatografia/instrumentação , Análise de Alimentos/instrumentação , Química Verde/métodos , Iodatos/análise , Iodatos/isolamento & purificação , Iodetos/química , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Microextração em Fase Líquida/métodos , Membranas Artificiais
6.
J Chromatogr A ; 1648: 462220, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-33992997

RESUMO

In this study, a new solid phase extraction method based on the use of a low-cost funnel-shaped partially carbonized cellulose filter paper as a sorbent has been developed. The sorbent is easily prepared by heating the folded filter paper wetted with sulfuric acid solution and can be reused for several times. It is combined with dispersive liquid-liquid microextraction and used for the extraction of some pesticide residues from fruit juice samples prior to their analysis by gas chromatography-flame ionization detection. In this work, limits of detection and quantification were in the ranges of 0.30-0.61 and 1.0-2.0 µg L-1, respectively, and relative standard deviations ranged between 3 and 6% for intra- (n=5) and inter-day (n=5) precisions at a concentration of 25 µg L-1 of each pesticide. The enrichment factors of 452-751 were achieved. Extraction recoveries were in the range of 45-75%. The calibration curves had wide linear ranges with a good linearity (coefficient of determination ≥ 0.994). Finally, efficiency of the method was apprised by determining the analytes in fruit juice samples and relative recoveries were found to be in the range of 85-101%.


Assuntos
Celulose/química , Sucos de Frutas e Vegetais/análise , Resíduos de Praguicidas/isolamento & purificação , Praguicidas/análise , Adsorção , Cromatografia Gasosa , Frutas/química , Química Verde , Microextração em Fase Líquida/métodos , Extração em Fase Sólida/métodos , Solventes/química
7.
Food Chem ; 358: 129817, 2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-33940302

RESUMO

In this paper, a green and inexpensive air-assisted natural deep eutectic solvent-based solidified homogeneous liquid phase microextraction procedure was optimized for extraction of patulin in fruit juice and dried fruit samples using experimental design prior to its spectrophotometric determination. Four different natural deep eutectic solvent were prepared and applied to ensure efficient, and selective extraction of patulin. The significant variables including Zn(II) amount, cooling time, pH and amount of natural deep eutectic solvent were optimized by using central composite design. Under optimized conditions, working range was 10-750 µg L-1 with 0.9996 of correlation coefficient. Detection limit and preconcentration factor were 3.5 µg L-1 and 150, respectively. The repeatability and reproducibility precision were in the range of 3.2-4.6% and 4.3-5.6% respectively. Recoveries ranging from 94% to 104% proved the accuracy of the method. The optimized method was successfully applied to the extraction and identification of patulin in the selected samples.


Assuntos
Sucos de Frutas e Vegetais , Frutas/química , Microextração em Fase Líquida/métodos , Patulina/isolamento & purificação , Química Computacional , Química Verde , Concentração de Íons de Hidrogênio , Limite de Detecção , Reprodutibilidade dos Testes , Projetos de Pesquisa , Solventes/química , Espectrofotometria Ultravioleta , Fatores de Tempo
8.
Artigo em Inglês | MEDLINE | ID: mdl-33957354

RESUMO

A novel in-syringe temperature-controlled liquid-liquid microextraction based on solidified floating ionic liquid (in-syringe TC-LLME-SFIL) combined with high performance liquid chromatography was developed for the simultaneous determination of monuron, chlorotoluron, atrazine, monolinuron, propazine and prometryn in commercial vegetable protein drinks. The samples were deproteinized by trichloroacetic acid and further cleaned up by solid phase extraction column. The ionic liquid tributyldodecylphosphonium tetrafluoroborate ([P4 4 4 12]BF4) was used as extraction solvent and dispersed into the depurated sample solution to form fine droplets with the assistance of heating and vortex. With the help of an ice bath, the ionic liquid phase solidified and floated on the surface of aqueous phase. After separation from the aqueous phase, the solidified ionic liquids were dissolved with acetonitrile and the resulting solution was analyzed by high performance liquid chromatography. Some extraction parameters, including type and amount of adsorbent, type and amount of ionic liquids, amount of NaCl, melting temperature and time of ionic liquid, vortex time, pH of sample solution, ice bath temperature and time, were investigated and optimized by single-factor experiment, Plackett-Burman design and Box-Behnken design. The results showed that good linearities (r ≥ 0.9994) were obtained in the concentration range of 7.8-1000.0 µg/L. The limits of detection and quantification were in the range of 0.25-2.59 µg/L and 0.82-8.63 µg/L, respectively. The spiked recoveries were 81.26-118.42% with the relative standard deviation (RSD, n = 3) lower than 8.17%. The present method was successfully applied to the simultaneous determination of triazine and phenylurea herbicides in vegetable protein drinks.


Assuntos
Sucos de Frutas e Vegetais/análise , Microextração em Fase Líquida , Resíduos de Praguicidas , Compostos de Fenilureia , Triazinas , Cromatografia Líquida de Alta Pressão/métodos , Herbicidas/análise , Herbicidas/isolamento & purificação , Líquidos Iônicos/química , Limite de Detecção , Modelos Lineares , Microextração em Fase Líquida/instrumentação , Microextração em Fase Líquida/métodos , Resíduos de Praguicidas/análise , Resíduos de Praguicidas/isolamento & purificação , Compostos de Fenilureia/análise , Compostos de Fenilureia/isolamento & purificação , Proteínas de Vegetais Comestíveis/análise , Reprodutibilidade dos Testes , Seringas , Triazinas/análise , Triazinas/isolamento & purificação
9.
J Chromatogr A ; 1645: 462099, 2021 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-33848658

RESUMO

In this study, a biosorbent material with characteristics for the adsorption of organic compounds was used for a cork pellet-based bar adsorptive microextraction technique, as a new greener alternative for the determination of organochlorine compounds. Aldrin, chlordane, dieldrin, endrin, lindane, 4,4-DDD, 4,4-DDE, 4,4-DDT, α-endosulfan and ß-endosulfan were analyzed in water samples (drinking water, stream water and river water) with separation/detection by gas chromatography and electron capture detection (GC/ECD). The parameters that can affect the sample preparation efficiency such as desorption solvent and time as well as extraction time and ionic strength were evaluated by multivariate and univariate designs. Cork pellets (10  ×  Ø 3 mm) were used for the extraction of 15 mL of sample in the optimal conditions: 60 min of agitation with no salt added to the sample, followed by desorption of the cork pellet with 120 µL of ethyl acetate for 30 min. The bar-to-bar RSD out with five different bars showed good results with RSD ≤ 15.6%, allowing the use of simultaneous extractions. LOD and LOQ values ranged from 3 to 15 ng L-1 and 10 to 50 ng L-1 respectively, and the determination coefficients were greater than 0.9869. The target analytes were not detected in the three analyzed samples. Therefore, the recovery study was performed fortifying the water samples. Analyte recovery ranged from 48.7 - 138.2% for drinking water, 40.2 - 128.2% for stream water and 67.5 - 128.7% for river water.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Hidrocarbonetos Clorados/análise , Microextração em Fase Líquida/métodos , Praguicidas/análise , Poluentes Químicos da Água/análise , Adsorção , Hidrocarbonetos Clorados/química , Hidrocarbonetos Clorados/isolamento & purificação , Limite de Detecção , Praguicidas/química , Praguicidas/isolamento & purificação , Reprodutibilidade dos Testes , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
10.
Molecules ; 26(5)2021 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-33806482

RESUMO

An effective and sensitive method is necessary for the determination of polybrominated diphenyl ethers (PBDEs) pollutants in water. In this study, effervescent-assisted dispersive liquid-liquid microextraction with solidification of the aqueous phase (EA-DLLME-SAP), followed by Gas Chromatography-Tandem Mass Spectrometry (GC-MS-MS) quantitative analysis, was established for the preconcentration and determination of PBDEs in real environmental water samples. 1,1,2,2-Tetrachloroethane was used as the extractant and directly dispersed into the water phase of the aqueous samples with the aid of a large number of carbon dioxide bubbles generated via the acid-base reaction of acetic acid and sodium bicarbonate, which did not require the use of a dispersant during the extraction process. The key factors affecting the extraction recovery were optimized, and an internal standard was used for quantitative analysis, which gave good linearity ranges of 1-100 ng·L-1 (BDEs 28, 47, 99, and 100), 2-200 ng·L-1 (BDEs 153, 154, and 183) and 5-500 ng·L-1 (BDE 209) with limits of quantification in the range of 1.0-5.0 ng·L-1. The accuracy was verified with relative standard deviations < 8.5% observed in tap, lake, river and reservoir water samples with relative recoveries ranging from 67.2 to 102.6%. The presented method contributes to the determination of PBDEs in environmental water samples.


Assuntos
Éteres Difenil Halogenados/análise , Hidrocarbonetos Bromados/análise , Microextração em Fase Líquida/instrumentação , Microextração em Fase Líquida/métodos , Poluentes Químicos da Água/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos
11.
J Chromatogr A ; 1646: 462132, 2021 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-33894455

RESUMO

In this work, a natural deep eutectic solvent (NADES) consisting of L-menthol and acetic acid in a 1:1 molar ratio has been applied as extraction solvent for the dispersive liquid-liquid microextraction based on the solidification of the floating organic drop (DLLME-SFO) of a group of nine phthalic acid esters (dipropyl phthalate, DPP; butyl benzyl phthalate, BBP; dibutyl phthalate, DBP; dicyclohexyl phthalate, DCHP; diisopentyl phthalate, DIPP; di-n-pentyl phthalate, DNPP; di(2-ethylhexyl) phthalate, DEHP; diisononyl phthalate, DINP; and diisodecyl phthalate, DIDP) from three common infusions (camomile, pennyroyal mint, and linden teas) and three soft drinks (green tea, tonic, and lime and lemon drink), using dihexyl phthalate (DHP) and di-n-octyl phthalate (DNOP) as internal standards. After the DLLME-SFO procedure, analyses were carried out by high-performance liquid chromatography with UV detection. Method calibration showed good linearity for all the analytes and matrices, with determination coefficients (R2) higher than 0.9910. Relative recovery values were between 71 and 125 %, with relative standard deviation values in the range 1-22 % for the six types of samples, while the limits of quantification of the method were in the range 4.3-51.1 µg/L for infusions and in the range 3.5-33.3 µg/L for soft drinks. Several samples purchased in different local supermarkets were analysed, finding DPP, DBP, DIPP, DEHP and DINP, although only DPP, DBP and DEHP could be quantified in some of them.


Assuntos
Bebidas Gaseificadas/análise , Microextração em Fase Líquida/métodos , Mentol/química , Ácidos Ftálicos/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Ésteres/química , Ácidos Ftálicos/química , Solventes/química
12.
Molecules ; 26(9)2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33919230

RESUMO

The content of active components in traditional Chinese medicine is relatively small, and it is difficult to detect some trace components with modern analytical instruments, so good pretreatment and extraction are very important in the experiment. Graphene was introduced by a dispersive liquid-liquid microextraction method based on solidification of floating organic drop (DLLME-SFO) with graphene/1-dodecyl alcohol used as the extractant, and this method, combined with quantitative proton nuclear magnetic resonance spectroscopy (1H-qNMR), was used to simultaneously qualitative and quantitative osthole, columbianadin and isoimperatorin in Angelicae Pubescentis Radix. In this experiment, a magnetic stirrer was used for extraction, all NMR spectra were recorded on a Bruker Advance III 600 MHz spectrometer with dimethyl sulfoxide-d6 (DMSO-d6) as deuterated solvent and pyrazine as the internal standard. The influencing factors and NMR parameters in the extraction process were investigated and optimized. In addition, the methodology of the established method was also examined. The quantitative signals of osthole, columbianadin and isoimperatorin were at a chemical shift of δ6.25-δ6.26 ppm, δ6.83-δ6.85 ppm, and δ6.31-δ6.32 ppm. The linear ranges of osthole, columbianadin and isoimperatorin were all 0.0455-2.2727 mg/mL, and R2 were 0.9994, 0.9994 and 0.9995, respectively. The limits of detection of osthole, columbianadin and isoimperatorin were 0.0660, 0.0720, 0.0620 mg, and the limits of quantification of osthole, columbianadin and isoimperatorin were 0.2201, 0.2401, 0.2066 mg/mL. The solution had good stability and repeatability within 24 h. The recoveries of osthole, columbianadin and isoimperatorin were 102.26%, 99.89%, 103.28%, respectively. The established method is simple and easy to operate, which greatly reduces the cumbersome pretreatment of samples and has high extraction efficiency.


Assuntos
Angelica/química , Cumarínicos/análise , Cumarínicos/isolamento & purificação , Grafite/química , Microextração em Fase Líquida , Espectroscopia de Ressonância Magnética , Microextração em Fase Líquida/métodos , Espectroscopia de Ressonância Magnética/métodos , Reprodutibilidade dos Testes , Solventes/química
13.
Molecules ; 26(8)2021 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-33918766

RESUMO

The analysis of controlled drugs in forensic matrices, i.e., urine, blood, plasma, saliva, and hair, is one of the current hot topics in the clinical and toxicological context. The use of microextraction-based approaches has gained considerable notoriety, mainly due to the great simplicity, cost-benefit, and environmental sustainability. For this reason, the application of these innovative techniques has become more relevant than ever in programs for monitoring priority substances such as the main illicit drugs, e.g., opioids, stimulants, cannabinoids, hallucinogens, dissociative drugs, and related compounds. The present contribution aims to make a comprehensive review on the state-of-the art advantages and future trends on the application of microextraction-based techniques for screening-controlled drugs in the forensic context.


Assuntos
Medicina Legal , Microextração em Fase Líquida/métodos , Preparações Farmacêuticas/análise , Microextração em Fase Sólida/métodos , Humanos , Drogas Ilícitas/análise
14.
Artigo em Inglês | MEDLINE | ID: mdl-33756450

RESUMO

A fast, sensitive and eco-friendly method was developed for the determination of fifteen polycyclic aromatic hydrocarbons (PAHs) in different environmental matrices through gas chromatography mass spectrometry (GC-MS). The method utilizes a modified and miniaturized quick easy cheap effective rugged and safe (QuEChERS) clean up procedure coupled to an air-assisted dispersive liquid-liquid microextraction (AA-DLLME) for the enrichment of the concerned compounds. The AA-DLLME uses diethyl carbonate (DEC) as a green bio-based solvent for the microextraction. DEC is considered as biodegradable (with octanol/water coefficient < 3, resulting in low potential of bioaccumulation), classified as a green solvent and considered as one of the recommended solvent alternatives based on SSG results. The AA-DLLME procedure was optimized by One-Variable-at-A-Time (OVAT) succeeded by experimental design applying Central Composite Face-centered (CCF) design. The method linear calibration was found in the range of 10-120 µg/Kg for Benzo[a]pyrene and 5-100 µg/Kg for all other PAHs with low detection limits ranging from 0.01 to 2.10 µg/Kg. It could enrich the PAHs up to 166-folds. The combination of modified µ-QuEChERS with the green AA-DLLME could sharply decrease the caffeine amount on the final extract injected to the GC-MS instrument. The method was successfully applied to coffee, tea, and water samples with acceptable % recovery (>90%). Finally, the impact of our procedure to the environment from green analytical chemistry view was assessed by a novel metric system called AGREE, proving the greenness of our procedure.


Assuntos
Café/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Microextração em Fase Líquida/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Chá/química , Cafeína/química , Dietil Pirocarbonato/análogos & derivados , Dietil Pirocarbonato/química , Química Verde , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes , Água/química
15.
Artigo em Inglês | MEDLINE | ID: mdl-33740692

RESUMO

Methotrexate, as a folate antagonist, is one of the first anti-neoplasm drugs offered and is still used as an effective drug in the treatment of various malignancies. Methotrexate has a narrow treatment index and is associated with numerous side effects.In thisresearch, for the first time a double-solvent supramolecular system (DSS) was developed as an extractant without disperser solvent for dispersive liquid-liquid microextraction (DLLME). DSS - DLLME was applied to the extraction of methotrexate in plasma of children with acute leukemiaprior to itsdetermination by high-performance liquid chromatography-ultraviolet detection (HPLC - UV). In the present method, two long normal chain alcohols are mixed in a particular ratio, and then it is injected into the sample solution, which is on the magnetic stirrer. In this case, the mixture of the two alcohol changes to new supramolecular aggregate. This new supermolecule is used as an extractant, which has a higher extraction power than any of its components alone. Under the optimum conditions, the calibration graph was linear in the rage of 0.1-150 µg L-1 with detection limit of 0.03 µg L-1. Relative standard deviations (RSDs) including intra-day and inter-day of method based on7 replicate determinations of 100.0 µg L-1of methotrexate were 2.6% and 4.8%,respectively. The results proved that DSS - DLLME is a sensitive, very simple, inexpensive, environmental friendly, rapid and efficient method for the preconcentration of trace amount of drugs in biological samples.


Assuntos
Leucemia/tratamento farmacológico , Microextração em Fase Líquida/métodos , Metotrexato/sangue , Doença Aguda , Criança , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Limite de Detecção , Modelos Lineares , Metotrexato/isolamento & purificação , Metotrexato/uso terapêutico , Reprodutibilidade dos Testes , Solventes/química
16.
J Chromatogr A ; 1642: 462036, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33714770

RESUMO

Biomonitoring is a potent tool to control the health risk of people occupationally and non-occupationally exposed. The latest trend in bioanalytical chemistry is to develop quick, cheap, easy, safe and reliable green analytical procedures to analyse a large number of chemicals in easily accessible biomatrices such as urine. In this paper, a new dispersive liquid-liquid microextraction (DLLME) procedure, conceived to treat urine samples and based on the use of a low transition temperature mixture (LTTM), was developed and validated to analyse twenty pesticides commonly used in farm practises. The LTTM was composed of choline chloride and sesamol in molar ratio 1:3 (ChCl:Ses 1:3); its characterization via differential scanning calorimetry identified it as an LTTM and not as a deep eutectic solvent due to the occurrence of a glass transition at -71 °C. The prepared mixture was used as the extraction solvent in the DLLME procedure, while ethyl acetate as the dispersing solvent. The salting out effect (50 mg mL-1 of NaCl in a diluted urine sample) improved the separation phase and the analyte transfer to the extractant. Due to the high ionic strength and despite the density of ChCl:Ses 1:3 (1.25 g mL-1), the LTTM layer floated on the top of the sample solution after centrifugation. All extracts were analysed by high-performance liquid chromatography coupled to mass spectrometry. After optimization and validation of the whole method, lower limits of quantitation were in the range of 0.02 - 0.76 µg  L-1. Extraction recoveries spanned from 50 to 101 % depending on the spike level and analytes. Precision and accuracy ranges were 3-18% and 5-20%, respectively. The extraction procedure was also compared with other methods, showing to be advantageous for rapidity, simplicity, efficiency, and low cost. Finally, urine samples from ten volunteers were effectively analysed using the developed method.


Assuntos
Cromatografia Líquida de Alta Pressão , Temperatura Baixa , Microextração em Fase Líquida/métodos , Espectrometria de Massas , Praguicidas/urina , Temperatura de Transição , Adulto , Varredura Diferencial de Calorimetria , Feminino , Humanos , Limite de Detecção , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Concentração Osmolar , Solventes/química , Fatores de Tempo , Adulto Jovem
17.
J Chromatogr A ; 1642: 462025, 2021 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-33721815

RESUMO

In this study, an elevated temperature liquid-liquid extraction combined method with successive air-assisted liquid-liquid microextraction has been proposed for the extraction of four phytosterols in cow milk butter and animal oil samples prior to gas chromatography-flame ionization detector. The method is started by combining a few grams of the melted butter or oil samples with ethanol. The mixture is vortexed and placed into a water-bath adjusted at 50 °C. After a few minutes, the mixture is allowed to cool at room temperature. In this step, the butter or oil is become stiff and ethanol is collected on top of the sample. The separated ethanol phase is collected and mixed with deionized water to obtain a homogenous solution. After that, a few microliters of ethyl methyl ammonium chloride: pivalic acid deep eutectic solvent is added into the solution and the mixture was pulled into a glass test tube and pushed back to the tube for five times. After centrifugation, whole of the collected phase at the bottom of tube was withdrawn and transferred into a microtube and contacted with sodium hydroxide solution. The mixture is withdrawn and released to the tube 2 times to remove the extracted fatty acids. The validation data verified that high enrichment factors (385-450) and extraction recoveries (77-90%), low limits of quantification (2.6-5.2 ng g-1) and detection (0.73-1.5 ng g-1), and satisfactory relative standard deviations (≤ 9.3%) can be obtained with this method. At last, the developed method was successfully used for the analysis of phytosterols in various butter and oil samples marketed in Tabriz, Iran.


Assuntos
Ar , Manteiga/análise , Microextração em Fase Líquida/métodos , Óleos/análise , Fitosteróis/análise , Animais , Cromatografia Gasosa , Ácidos Graxos/análise , Leite/química , Reprodutibilidade dos Testes , Solventes/análise , Temperatura , Fatores de Tempo , Água/análise
18.
J Chromatogr A ; 1643: 462034, 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33744655

RESUMO

Volatile fatty acids (VFAs) are key parameters to monitor anaerobic digestion processes. Thus, a fast, simple and precise determination of these analytes is necessary for a timely characterization of the biological processes present in municipal solid waste and wastewater treatment plants. In this work, an automated method for the extraction and preconcentration of VFAs, based on dispersive liquid-liquid microextraction with magnetic stirring in syringe, and gas chromatography with flame ionization detector for the separation and detection, is described. The effect of parameters such as the type and volume of extraction solvent, pH, salting out effect and stirring time, was studied using a multivariate and univariate experimental design. Extraction and preconcentration were performed simultaneously using tert-butyl methyl ether (TBME) as the extraction solvent, after stirring 100 s at a constant rate. The detection limits were in the range of 0.1 - 1.3 mg L-1 and a good linearity was observed up to 1000 mg L-1 of the studied VFAs, with a range of R2 between 0.9997 and 0.9999. The intra and interday precision expressed as relative standard deviation (n= 5) varied between 0.7 and 2.4% and between 1.7 and 7.0%, respectively. Subsequently, the developed method was successfully applied to evaluate the presence of VFAs in wastewater samples from anaerobic treatments and an average relative recovery of 102% was obtained.


Assuntos
Cromatografia Gasosa/métodos , Ácidos Graxos Voláteis/análise , Ionização de Chama/instrumentação , Microextração em Fase Líquida/métodos , Magnetismo , Anaerobiose , Automação , Reatores Biológicos , Destilação , Limite de Detecção , Análise Multivariada , Sais/química , Solventes/química , Fatores de Tempo , Águas Residuárias/química
19.
Food Chem ; 352: 129331, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33652198

RESUMO

A novel density-tunable liquid-phase microextraction (DT-LPME) system was developed with high-density deep eutectic solvents (DESs) as extractant and low-density organic solvents as emulsifier and density regulator. DES-rich phase was induced to form in the bottom or in the top by adjusting the emulsifier amount. This system was used to directly extract polycyclic aromatic hydrocarbons (PAHs) from liquid and solid foods, and the obtained DES-rich phase was easy to be collected for quantification. The method (LPME with HPLC-fluorescence detector) has linearity (R2 > 0.9974), detection limits of 0.6-4.2 ng L-1 for liquid foods and 0.05-0.35 ng g-1 for solid foods, recoveries of 86.2-114.9%, and intra-day/inter-day RSDs below 6.6%. The method was applied to detect PAHs in real samples, and the PAHs residue was found in honey and five solid foods. The DT-LPME method is simple, fast, green and suitable for direct extraction of analytes from both liquid and solid samples.


Assuntos
Microextração em Fase Líquida/métodos , Plantas Medicinais/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Solventes/química , Chá/química , Análise de Alimentos , Mel/análise , Limite de Detecção
20.
J Chromatogr A ; 1643: 462058, 2021 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-33756356

RESUMO

A reverse micelle mediated dispersive liquid-liquid microextraction (RM-DLLME) combined with high performance liquid chromatography-ultraviolet detector (HPLC-UV) was developed for extraction and determination of 5 A2 components of teicoplanin (TA2-1, TA2-2, TA2-3, TA2-4, TA2-5) in human plasma, and the mechanism of RM-DLLME was analysed and explored. In this method, 80 µL of the reverse micelle solution of cetylpyridinium chloride/n-hexanol (15 mmol/L) was used as the extraction solvent for the separation, extraction and enrichment of the teicoplanin in plasma sample. All factors affecting the extraction efficiencies of the target analytes, such as the amounts of acetonitrile and chloroform, the type and volume of reverse micelle solution, pH and volume of sample phase, dispersant, salt addition, extraction mode and time, centrifugation rate and time, were investigated and optimized. Under the optimum conditions, the 5 A2 components of teicoplanin achieved effective enrichment with the enrichment factors of 228-347 and obtained good linearity in the range of 0.8375-100.5 µg/mL with correlation coefficients higher than 0.9960. The limits of detection were ranged between 0.5025-3.015 µg/mL. Relative standard deviation values of the method precisions were lower than 10.6% and the average recoveries were in the range of 82.7-111.3%. The determination results of the method were demonstrated with favorable characteristics, such as high enrichment, good selectivity and sensitivity, satisfactory precision and accuracy, and this method could be employed to analysis of the teicoplanin in human plasma samples.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Líquida/métodos , Micelas , Teicoplanina/sangue , Humanos , Concentração de Íons de Hidrogênio , Limite de Detecção , Reprodutibilidade dos Testes , Espectrofotometria Ultravioleta , Teicoplanina/química , Teicoplanina/isolamento & purificação
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