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1.
Molecules ; 27(19)2022 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-36234806

RESUMO

An in situ coacervative extraction (IS-CAE) based on a double-solvent supramolecular system coupled to liquid-liquid microextraction is investigated for extraction and enrichment of triazole fungicides. The formation of a double-solvent supramolecular system was generated by in situ formation and used as an extraction solvent for the coacervative extraction method. No disperser solvent was required. This new double-solvent supramolecular system has a higher extraction ability than any of its components alone. The different factors that could affect the extraction capability were studied and optimized, including the type of double extractant and its volume, salt addition, vortex time, and centrifugation time. Under optimum extraction conditions, this method provides high enrichment factors (EFs) of 73-318 with low limits of detection (LODs) of 0.3-1 µg L-1 and limits of quantitation (LOQs) of 1-3 µg L-1. In addition, the proposed method was prosperously applied for the determination of triazole fungicides in water, fruit juice, and soy milk samples.


Assuntos
Fungicidas Industriais , Microextração em Fase Líquida , Cromatografia Líquida de Alta Pressão , Fungicidas Industriais/análise , Microextração em Fase Líquida/métodos , Solventes/química , Triazóis/análise , Água/análise
2.
J Sep Sci ; 44(19): 3636-3645, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34355518

RESUMO

A new type of magnetic material based on silica-coated mixed iron hydroxides functionalized with deep eutectic solvent was utilized for the magnetic solid-phase extraction of organochlorine pesticides prior to gas chromatography-mass spectrometry analysis. Choline chloride and phenol were selected as the hydrogen bond acceptor and donor, respectively, for preparing the deep eutectic solvent-modified magnetic surface. The modified surface possessed superior enrichment capability for organochlorine pesticides. Under optimal extraction conditions, viz., 10 mg sorbent, 5 mL sample solution, and 200 µL acetone (desorption solvent), linearity was obtained in the range 0.005-200 µg/L, with coefficients of determination greater than 0.997. The limits of detection and quantification were as low as 0.6-10 and 5-60 ng/L, respectively, whereas the enrichment factors were in the range of 31-100. The precisions evaluated in terms of the relative standard deviations of the intra- and inter-day experiments were <4.9 and 7.6%, respectively. The developed method was successfully applied for determining the organochlorine residues in agricultural products. Satisfactory recoveries in the range of 71.2-110.3% were obtained, with a relative standard deviation of <8.0%. The proposed material is a promising sorbent for the preconcentration of organochlorine residues.

3.
Molecules ; 27(1)2021 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-35011271

RESUMO

A single-step preconcentration procedure using the in-situ formation of modified nickel-zinc-layered double hydroxides (LDHs) prior to high-performance liquid chromatography (HPLC) is investigated for the determination of neonicotinoid insecticide residues in honey samples. The LDHs could be prepared by the sequential addition of sodium hydroxide, sodium dodecyl sulfate, nickel nitrate 6-hydrate and zinc nitrate 6-hydrate, which were added to the sample solution. The co-precipitate phase and phase separation were obtained by centrifugation, and then the precipitate phase was dissolved in formic acid (concentrate) prior to HPLC analysis. Various analytical parameters affecting extraction efficiency were studied, and the characterization of the LDHs phase was performed using Fourier-transformed infrared spectroscopy and scanning electron microscopy. Under optimum conditions, the limit of detection of the studied neonicotinoids, in real samples, were 30 µg L-1, for all analytes, lower than the maximum residue limits established by the European Union (EU). The developed method provided high enrichment, by a factor of 35. The proposed method was utilized to determine the target insecticides in honey samples, and acceptable recoveries were obtained.


Assuntos
Hidróxidos/química , Inseticidas/química , Neonicotinoides/química , Níquel/química , Compostos de Zinco/química , Zinco/química , Cromatografia Líquida de Alta Pressão , Mel/análise , Inseticidas/análise , Neonicotinoides/análise , Espectroscopia de Infravermelho com Transformada de Fourier
4.
J Sep Sci ; 43(15): 3083-3092, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32445251

RESUMO

The present work describes a simple route to magnetize MIL-53(Al)-NH2 sorbent for rapid extraction of phenol residues from environmental samples. To extend the applications and performances of the metal-organic frameworks in the field of adsorption materials, we combined the properties of metal-organic frameworks and magnetite to decrease the extraction time and simplify the extraction process as well. In this study, a simple and quick vortex-assisted dispersive magnetic solid phase extraction method for the extraction of ten United States Environmental Protection Agency's priority phenols from water samples prior to analysis by high-performance liquid chromatography with photodiode array detection was proposed. The developed method exhibits a rapid enrichment of the target analytes within 10 s for extraction and 10 s for desorption. Low detection limits of 1.8-41.7 µg/L and quantitation limits of 6.0-139.0 µg/L with the relative standard deviations for intra- and interday analyses less than 12% were achieved. Satisfactory recoveries in the range of 80-111% with the relative standard deviations less than 11% demonstrated that Fe3 O4 /MIL-53(Al)-NH2 is promising sorbent in the field of magnetic solid-phase extraction for environmental samples.

5.
Molecules ; 25(12)2020 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-32560233

RESUMO

A green, simple and sensitive hydrophobic DES-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography (HPLC) was developed for the analysis of neonicotinoid insecticide residues in various samples. A hydrophobic deep eutectic solvent (DES) was synthesized using decanoic acid as a hydrogen bond donor and tetrabutylammonium bromide (TBABr) as a hydrogen bond-acceptor. DESs were synthesized and characterized by Fourier transform-infrared (FTIR) spectroscopy. Two disperser solvents were substituted with surfactants and acetonitrile, which could afford more effective emulsification and make the extraction relatively greener. The hydrophobic DES extraction phase occurred 10 min after centrifugation, being easy to be collected for analysis. Several parameters were investigated and optimized. Under the optimum condition, the calibration curve of this method was linear in the range of 0.003-1.0-µg·mL-1, with a correlation coefficient (R2) higher than 0.99 and a good repeatability, with the relative standard deviations (RSDs) were less than 5.00%. The limits of detection were in the range of 0.001-0.003 µg·mL-1; the limits of quantitation were in the range of 0.003-0.009 µg·mL·mL-1. Finally, the presented method was implemented to determine the neonicotinoid insecticide residues in water, soil, egg yolk samples and acceptable recoveries were obtained.


Assuntos
Gema de Ovo/química , Inseticidas/análise , Neonicotinoides/análise , Resíduos de Praguicidas/análise , Solo/química , Água/análise , Microextração em Fase Líquida , Espectroscopia de Infravermelho com Transformada de Fourier
6.
Molecules ; 24(21)2019 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-31683714

RESUMO

An efficient and environment-friendly microextraction method, namely, ß-cyclodextrin assisted liquid-liquid microextraction, based on solidification of the floating organic droplets method coupled with HPLC is investigated for the sensitive determination of trace neonicotinoid pesticide residues. In this method, ß-cyclodextrin is used as a disperser solvent, while 1-octanol is selected as an extraction solvent. ß-cyclodextrins was found to decrease interfacial tension and increase the contact area between the organic and water phases with the help of centrifugation. A cloudy solution was rapidly formed and then centrifuged to complete phase separation. Various key parameters influencing extraction efficiency were systematically investigated and optimized; they include salt addition, concentration of ß-cyclodextrin, and volume of extraction solvent (1-octanol). Under optimum conditions, good linearity was obtained with coefficient for determination (R2) greater than 0.99. A low limit of detection, high enrichment factor, and good recovery (83 - 132) were achieved. This proves that the proposed method can be applied to determine trace neonicotinoid pesticide residues in natural surface water samples.


Assuntos
Microextração em Fase Líquida/métodos , Neonicotinoides/análise , Resíduos de Praguicidas/análise , beta-Ciclodextrinas/química , 1-Octanol/química , Padrões de Referência , Sais/química , Água/química
7.
Molecules ; 23(5)2018 05 12.
Artigo em Inglês | MEDLINE | ID: mdl-29757232

RESUMO

An effective pre-concentration method, namely amended-cloud point extraction (CPE), has been developed for the extraction and pre-concentration of neonicotinoid insecticide residues. The studied analytes including clothianidin, imidacloprid, acetamiprid, thiamethoxam and thiacloprid were chosen as a model compound. The amended-CPE procedure included two cloud point processes. Triton™ X-114 was used to extract neonicotinoid residues into the surfactant-rich phase and then the analytes were transferred into an alkaline solution with the help of ultrasound energy. The extracts were then analyzed by high-performance liquid chromatography (HPLC) coupled with a monolithic column. Several factors influencing the extraction efficiency were studied such as kind and concentration of surfactant, type and content of salts, kind and concentration of back extraction agent, and incubation temperature and time. Enrichment factors (EFs) were found in the range of 20⁻333 folds. The limits of detection of the studied neonicotinoids were in the range of 0.0003⁻0.002 µg mL−1 which are below the maximum residue limits (MRLs) established by the European Union (EU). Good repeatability was obtained with relative standard deviations lower than 1.92% and 4.54% for retention time (tR) and peak area, respectively. The developed extraction method was successfully applied for the analysis of water samples. No detectable residues of neonicotinoids in the studied samples were found.


Assuntos
Fracionamento Químico , Inseticidas/química , Neonicotinoides/química , Resíduos de Praguicidas/química , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão , Inseticidas/análise , Neonicotinoides/análise , Resíduos de Praguicidas/análise , Ultrassom
8.
Environ Sci Technol ; 51(18): 10652-10662, 2017 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-28813145

RESUMO

The continuous release of pharmaceuticals and personal care products (PPCPs) into freshwater systems impacts the health of aquatic organisms. This study evaluates the concentrations and bioaccumulation of PPCPs and the selective uptake of antidepressants in fish from the Niagara River, which connects two of the North American Great lakes (Erie and Ontario). The Niagara River receives PPCPs from different wastewater treatment plants (WWTPs) situated along the river and Lake Erie. Of the 22 targeted PPCPs, 11 were found at part-per-billion levels in WWTP effluents and at part-per-trillion levels in river water samples. The major pollutants observed were the antidepressants (citalopram, paroxetine, sertraline, venlafaxine, and bupropion, and their metabolites norfluoxetine and norsertraline) and the antihistamine diphenhydramine. These PPCPs accumulate in various fish organs, with norsertraline exhibiting the highest bioaccumulation factor (up to about 3000) in the liver of rudd (Scardinius erythrophthalmus), which is an invasive species to the Great Lakes. The antidepressants were selectively taken up by various fish species at different trophic levels, and were further metabolized once inside the organism. The highest bioaccumulation was found in the brain, followed by liver, muscle, and gonads, and can be attributed to direct exposure to WWTP effluent.


Assuntos
Antidepressivos/farmacocinética , Peixes , Poluentes Químicos da Água/farmacocinética , Animais , Monitoramento Ambiental , Ontário , Preparações Farmacêuticas , Rios , Distribuição Tecidual , Eliminação de Resíduos Líquidos
9.
Acta Chim Slov ; 64(3): 590-597, 2017 09.
Artigo em Inglês | MEDLINE | ID: mdl-28862309

RESUMO

An ionic liquid-assisted liquid-liquid microextraction based on the solidification of floating organic droplet (ILSFODLLME) was investigated for analysis of four herbicide residues (i.e. simazine, atrazine, propazine, and linuron) by high performance liquid chromatography. For ILSFOD-LLME, the optimal extraction conditions were 5% w/v Na2SO4, 30 µL [C4MIM][PF6]RTIL, 100 µL of 1-octanol, ultrasonication time 30 s and centrifugation at 5000 rpm for 5 min. Under the optimal conditions, linearity was obtained within the range of 0.1-1000 µg kg-1, with the correlation coefficients greater than 0.999. The high enrichment factors of the target analytes were in the range of 64.5-139.9 and low limit of detection could be obtained. A modified QuEChERS was applied for fruit sample preparation before analysis. Matrix effects were also investigated using matrix matched standards for construction of the calibration graph. The proposed method has been successfully applied for extraction and preconcentration of herbicide residues in fruit samples, and good recoveries in the range of 87.32% to 99.93% were obtained.

10.
J Sep Sci ; 37(16): 2138-44, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24890905

RESUMO

Liquid chromatographic assays were developed using a mixed-mode column coupled in sequence with a hydrophilic interaction liquid chromatography column to allow the simultaneous comprehensive analysis of inorganic/organic anions and cations, active pharmaceutical ingredients, and excipients (carbohydrates). The approach utilized dual sample injection and valve-mediated column switching and was based upon a single high-performance liquid chromatography gradient pump. The separation consisted of three distinct sequential separation mechanisms, namely, (i) ion-exchange, (ii) mixed-mode interactions under an applied dual gradient (reversed-phase/ion-exchange), and (iii) hydrophilic interaction chromatography. Upon first injection, the Scherzo SS C18 column (Imtakt) provided resolution of inorganic anions and cations under isocratic conditions, followed by a dual organic/salt gradient to elute active pharmaceutical ingredients and their respective organic counterions and potential degradants. At the top of the mixed-mode gradient (high acetonitrile content), the mobile phase flow was switched to a preconditioned hydrophilic interaction liquid chromatography column, and the standard/sample was reinjected for the separation of hydrophilic carbohydrates, some of which are commonly known excipients in drug formulations. The approach afforded reproducible separation and resolution of up to 23 chemically diverse solutes in a single run. The method was applied to investigate the composition of commercial cough syrups (Robitussin®), allowing resolution and determination of inorganic ions, active pharmaceutical ingredients, excipients, and numerous well-resolved unknown peaks.


Assuntos
Química Farmacêutica/métodos , Cromatografia por Troca Iônica , Cromatografia Líquida , Acetonitrilas/química , Ânions/análise , Carboidratos/química , Cátions/análise , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Expectorantes/análise , Guaifenesina/análise , Interações Hidrofóbicas e Hidrofílicas
11.
J Food Sci Technol ; 51(4): 664-72, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24741159

RESUMO

A cloud-point extraction (CPE) was developed for the determination of 12 phenolic compounds (i.e. gallic acid, procatechuic acid, p-hydroxybenzoic acid, vanillic acid, caffeic acid, syringic acid, p-coumaric acid, ferulic acid, guaiacol, p-cresol, o-cresol and 3,5-xylenol) using reversed-phase high performance liquid chromatography (RP-HPLC) with photodiode array (PDA) detection. The optimum CPE conditions were 2.0% (w/v) Triton X-114, 3.0% (w/v) Na2SO4 and 20-min equilibrated at 45 °C. The surfactant-rich phase was then analyzed by HPLC using a Symmetry C18 column, gradient mobile phase of acetonitrile and 1% (v/v) acetic acid, and PDA detection at 280 nm. Under the optimum condition, the target phenolic compounds were separated within 25 min. CPE gave higher enrichment factor up to 15-fold compared to that of direct analysis. The proposed method showed good analytical performances with limits of detection in the range 0.01-0.1 mg L(-1) and precisions with relative standard deviation (RSD) lower than 5% for retention time and 10% for peak area. The method was successfully applied to the analysis of phenolic compounds in Thai local wine samples. Gallic acid, procatechuic acid, and vanillic acid were the highest phenolics found in the studied wines with the contents up to 172.4, 99.1, and 26.6 mg L(-1), respectively. The recovery of the spiked wine samples (0.5, 1.0, and 2.0 mg L(-1)) were obtained in the range of 90.4-110%. High total phenolic content, total flavonoids, and antioxidant activity (DPPH method) in the studied wines were also observed.

12.
Food Chem ; 441: 138325, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38183727

RESUMO

An eco-friendly biomass waste-derived magnetic material coated with a dual-dummy-template molecularly imprinted polymer was fabricated using aqueous ethanol as a green porogen, lower amounts of toxic compounds as template molecules, and tyrosine and tryptophan as biocompatible binary monomers. The binding characteristics and selectivity of the material toward pesticides were assessed. High adsorption capacities ranging from 150.11 to 509.09 mg g-1 and imprinting factors reaching 2.2 were achieved within just 30 s. The material was applied for extraction of organophosphorus and carbamate pesticides prior to HPLC analysis. Under the optimum conditions, low limits of detection and quantitation were achieved, with ranges of 0.05-1.49 µg/L and 0.18-5.00 µg/L, respectively. The established approach enables efficient analysis of vegetable and fruit samples, yielding satisfactory recoveries ranging between 80 and 110 %. The method showed promise as an analytical method for the sensitive enrichment of pesticide residues in vegetable and fruit samples.


Assuntos
Impressão Molecular , Praguicidas , Polímeros Molecularmente Impressos , Polímeros/química , Biomassa , Praguicidas/análise , Adsorção , Carbamatos , Fenômenos Magnéticos , Impressão Molecular/métodos , Extração em Fase Sólida/métodos , Cromatografia Líquida de Alta Pressão/métodos
13.
Talanta ; 270: 125536, 2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38101032

RESUMO

Biodegradable molecularly imprinted polymer-coated paper (MIP@paper) was effectively produced by polymerization using azinphos-methyl as a template molecule, terephthalic acid as a functional monomer, ethylene glycol dimethacrylate as a cross-linker, and aqueous ethanol as a green porogenic solvent. The material was subsequently composited onto cellulose paper, which served as the natural substrate, by dip coating with the aid of chitosan and citric acid natural adhesive. The properties, such as static and dynamic adsorption, selectivity, and reusability, were assessed. At rapid adsorption equilibrium (10 min), the MIP@paper had a high adsorption capacity in the range of 2.5-3.7 mg g-1 and good recognition with imprinting factors up to 2.1. In addition, the proposed MIP@paper was utilized efficiently as a sorbent for dispersive solid phase extraction (d-SPE) of eight organophosphorus pesticides (OPPs) prior to high-performance liquid chromatography (HPLC) analysis. The d-SPE-HPLC method displayed low detection limits of 1.2-4.5 µg kg-1 and significant enrichment factors (up to 320-fold). The proposed method was effectively applied for the determination of OPP residues in agricultural products, including fruits, vegetables, and cereal grains, with satisfactory spiked recoveries (80.1-119.1 %). Thus, the MIP@paper material provided a selective and environmentally favorable method for extracting and determining organophosphorus pesticides.


Assuntos
Impressão Molecular , Praguicidas , Praguicidas/análise , Verduras/química , Polímeros Molecularmente Impressos/análise , Compostos Organofosforados/análise , Grão Comestível/química , Frutas/química , Extração em Fase Sólida/métodos , Impressão Molecular/métodos , Adsorção , Cromatografia Líquida de Alta Pressão/métodos
14.
J Chromatogr A ; 1712: 464494, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-37951046

RESUMO

A new magnetic molecularly imprinted polymer was successfully synthesized using a ternary deep eutectic solvent derived from caffeic acid-choline chloride-formic acid as a functional monomer, thymol-menthol deep eutectic solvent as a template, ethylene glycol dimethacrylate as a cross-linker, potassium peroxodisulfate as an initiator, and aqueous ethanol solution (90% (v/v)) as a porogen. The synthesized material was characterized and applied for magnetic solid-phase extraction of dichlorodiphenyl trichloroethane and its degradation products. Optimization of the extraction condition was carried out using the central composite design and response surface methodology. The good analytical performance of magnetic solid phase extraction/gas chromatography‒mass spectrometry using the proposed adsorbent shows a wide linear range of 0.07-500 ng g-1 with R2 greater than 0.992. Low detection limits and quantitation limits were observed in the ranges of 0.01-2.00 ng g-1 and 0.07-2.50 ng g-1, respectively. The precisions shown in terms of relative standard deviations were lower than 7.0% for intraday (n=5) and 8.6% for interday (n=5 × 3) experiments. The proposed method was applied for preconcentration and determination of dichlorodiphenyl trichloroethane and its degradation products in fruit and vegetable samples. The satisfactory recoveries of the real samples at three spiked concentrations were obtained in the range of 79.1%-110.9% with RSDs lower than 7.5%. The findings highlight the importance of developing efficient sorbents for the enrichment of persistent organic pollutants in food matrices.


Assuntos
Impressão Molecular , Polímeros Molecularmente Impressos , Solventes/química , Verduras , Solventes Eutéticos Profundos , Tricloroetanos , Frutas , Polímeros/química , Extração em Fase Sólida , Fenômenos Magnéticos , Impressão Molecular/métodos
15.
RSC Adv ; 13(13): 8863-8872, 2023 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-36936839

RESUMO

A green solvent of ternary deep eutectic solvent (menthol-thymol-dodecanoic acid) was prepared and used as a functional reagent to modify a magnetic mixed iron hydroxide@MIL-101(Cr)-NH2 composite. The proposed sorbent (MIH@MIL-101(Cr)-NH2-TDES) was applied in magnetic solid phase extraction (MSPE) for the enrichment of organochlorine pesticides. The analytes were quantitively analyzed by GC-MS. The relationships of experimental parameters for preparing the proposed sorbent and the MSPE method were studied through a Box-Behnken design and a central composite design, respectively. Their optimized conditions were investigated using response surface methodology. Application of the MIH@MIL-101(Cr)-NH2-TDES sorbent in MSPE successfully enhanced the sensitivity of GC-MS analysis, giving enrichment factors in the range of 56-168. The MSPE/GC-MS method was developed using MIH@MIL-101(Cr)-NH2-TDES as a sorbent and was successfully employed for the preconcentration/determination of organochlorine residues in honey and tea samples. The satisfactory detection limits were in the ranges of 0.07-0.80 ng g-1 and 0.7-8.5 ng g-1 for honey and tea samples, respectively. Acceptable recoveries were obtained in the ranges of 81.7-107.3% and 85.4-109.3% for the spiked honey and tea samples, respectively, with RSDs lower than 10.0%.

16.
Food Chem ; 418: 136045, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-36996646

RESUMO

An eco-friendly magnetic dual-dummy-template molecularly imprinted polymer (MDDMIP) was prepared by a "one-pot" green synthesis using mixed-valence iron hydroxide as the magnetic material, a deep eutectic solvent as the coporogen, and caffeic acid and glutamic acid as binary monomers. The adsorption properties toward organophosphorus pesticides (OPPs) were investigated. High adsorption capacities (269.65-304.93 mg g-1), quick adsorption times (20 s), and high imprinting factors (2.28-3.83) were obtained. The proposed MDDMIP was utilized for magnetic solid phase extraction (MSPE) of OPPs prior to quantification by high performance liquid chromatography (HPLC). The developed method exhibited outstanding linearity (0.05-500 µg L-1), low detection limits (0.003-0.015 µg L-1), and excellent enrichment factors (940-1310 folds). The MSPE-HPLC method was successfully applied for the detection of OPPs in vegetable, fruit, and grain samples with acceptable recoveries (80-119%). This method is a good potential method for the analysis of pesticide residues in complex matrices.


Assuntos
Impressão Molecular , Praguicidas , Solventes/química , Polímeros Molecularmente Impressos , Solventes Eutéticos Profundos , Organofosfatos , Polímeros/química , Compostos Organofosforados , Extração em Fase Sólida/métodos , Adsorção , Fenômenos Magnéticos , Impressão Molecular/métodos , Cromatografia Líquida de Alta Pressão/métodos
17.
J Sep Sci ; 35(18): 2373-89, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22997028

RESUMO

This review covers recent developments in sample preparations and analytical techniques for determination of residues of carbamate pesticides. Special attention is paid to the newly established microextraction techniques, including cloud-point extraction, dispersive liquid-liquid microextraction, and ultrasound-assisted surfactant-enhanced emulsification microextraction. In addition, extractions using a variety of solvents, as well as miniaturized and on-line sample preparation systems, are discussed. Applications of the different methods for the determination of carbamate pesticide residues in food and environmental matrices are included.


Assuntos
Métodos Analíticos de Preparação de Amostras/métodos , Carbamatos/análise , Fracionamento Químico , Estrutura Molecular , Espectrofotometria
18.
J Chromatogr A ; 1673: 463111, 2022 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-35525191

RESUMO

A newly designed magnetic layered double hydroxide composite modified with a natural deep eutectic solvent derived from choline chloride and sucrose was synthesized and applied as a sorbent for the enrichment of organochlorine pesticides. The magnetic solid phase extraction (MSPE) procedure was optimized via a small central composite design and response surface methodology. The MSPE method was able to preconcentrate the organochlorine residues in environmental samples prior to GC-MS analysis. Good analytical performance of the proposed method was observed with an enrichment factor of up to 158 and low limits of detection in the ranges of 0.002-0.015 µg·L-1 and 0.03-0.10 ng·g-1 for water and soil, respectively. Satisfactory recoveries for spiked water and soil samples were obtained in the ranges of 80.9-104.7% (RSDs<7.9) and 88.8-104.1% (RSDs<7.3), respectively. This finding highlights the role of natural deep eutectic solvents as modifying agents for magnetic layered double hydroxides, which enhance the efficiency of extraction of the target analytes. The developed MSPE/GC-MS procedure was sensitive and reliable for the determination of trace organochlorine residues in environmental samples.


Assuntos
Hidrocarbonetos Clorados , Praguicidas , Solventes Eutéticos Profundos , Hidrocarbonetos Clorados/análise , Hidróxidos/análise , Limite de Detecção , Fenômenos Magnéticos , Praguicidas/análise , Solo , Extração em Fase Sólida/métodos , Solventes/química , Água/análise
19.
ACS Omega ; 7(14): 12202-12211, 2022 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-35449973

RESUMO

Magnetic sorbents based on iron-aluminum-mixed metal hydroxides composited with metal-organic frameworks (MOFs) were designed and synthesized using different benzoate ligands, including terephthalic acid, 2-aminoterephthalic acid, 2,5-dihydroxyterephthalic acid, 1,3,5-benzenetricarboxylic acid, and 1,2,4,5-benzenetetracarboxylic acid. The magnetic MOF derived from terephthalic acid ligand exhibited an excellent extraction efficiency, with adsorption capacities in the range of 2193-4196 mg kg-1, and was applied for magnetic solid-phase extraction (MSPE) of carbamate pesticides, that is, bendiocarb, carbosulfan, carbofuran, carbaryl, propoxur, isoprocarb, and promecarb. Simple digital image colorimetry based on the diazotization reaction and high-performance liquid chromatography (HPLC) were utilized for fast screening and quantification purposes, respectively. A good analytical performance for a simple screening approach using portable equipment was obtained with detection limits in the range of 1.0-18.0 µg L-1. Under the optimized MSPE-HPLC conditions, the entire developed procedure provided a wide linear range between 0.015 and 1000 µg L-1, low limits of detection, and limits of quantitation ranging from 0.005 to 0.090 and 0.015-0.300 µg L-1, respectively. Enrichment factors up to 184 were achieved. The intra- and interday relative standard deviations were below 6.7 and 9.4%, respectively. The proposed MSPE-digital image colorimetry and MSPE-HPLC methods were successfully applied for screening and determining carbamate pesticides in fruits and vegetables. The recoveries were obtained in a satisfactory range of 71.5-122.8%. This discovery has led to the development of integration methods using newly synthesized sorbent materials for the enrichment of carbamate pesticides prior to their analysis in complicated samples. The developed MSPE coupled with digital image colorimetry was efficient for fast carbamate contamination screening, while MSPE-HPLC offered a sensitive analytical methodology for quantifying contaminated samples.

20.
Food Chem ; 384: 132475, 2022 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-35189433

RESUMO

A water-compatible magnetic dual template molecularly imprinted polymer using a ternary deep eutectic solvent as a functional monomer was synthesized via a green synthesis method based on one-pot reversible addition/fragmentation chain transfer precipitation polymerization. The resulting material, DES-MDMIP, shows excellent adsorption capacity (218.62 mg g-1) in rapid adsorption time (30 s) and outstanding selectivity factors of 4.45 for organophosphorus pesticides. The sorbent was applied in magnetic solid-phase extraction prior to HPLC analysis. The developed methodology provides linearity between 0.05 and 2000.00 µg L-1. Low detection limits of 0.015-0.030 µg L-1 and enrichment factors of up to 691 were achieved. The applicability of the method facilitates the efficient determination of fruit and vegetable samples with satisfactory recoveries in the range of 80-117%. The newly designed water-compatible DES-MDMIP sorbent, along with a simple and rapid extraction process, demonstrated a powerful analytical approach for the practical analysis of pesticide residues.


Assuntos
Impressão Molecular , Praguicidas , Adsorção , Solventes Eutéticos Profundos , Frutas/química , Fenômenos Magnéticos , Polímeros Molecularmente Impressos , Compostos Organofosforados/análise , Praguicidas/análise , Extração em Fase Sólida , Solventes/química , Verduras , Água
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