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1.
J Chromatogr A ; 1726: 464972, 2024 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-38744184

RESUMO

The effect of internal and external magnetic fields on the separation of antifungal drugs by centrifugal acceleration thin-layer chromatography was reported for the first time. External and internal magnetic fields were applied using neodymium magnets and CoFe2O4@SiO2 ferromagnetic nanoparticles. Separation of ketoconazole and clotrimazole was performed using a mobile phase consisting of n-hexane, ethyl acetate, ethanol, and ammonia (2.0:2.0:0.5:0.2, v/v). The influence of the magnetic field on the entire chromatographic system led to changes in the properties of the stationary and mobile phases and the analytes affecting the retention factor, shape, and width of the separated rings. The extent of this impact depended on the structure of the analyte and the type and intensity of the magnetic field. In the presence of the external magnetic field, there were more significant changes in the chromatographic parameters of the drugs, especially the width of the separated rings, and ketoconazole was more affected than clotrimazole. The changes are conceivably due to the effect of the magnetic field on the analyte distribution between the stationary and mobile phases, which is also caused by the possibility of the magnetic field affecting the viscosity, surface tension, and surface free energy between the stationary and mobile phases.


Assuntos
Antifúngicos , Cetoconazol , Campos Magnéticos , Cromatografia em Camada Fina/métodos , Antifúngicos/análise , Antifúngicos/química , Antifúngicos/isolamento & purificação , Cetoconazol/química , Cetoconazol/análise , Clotrimazol/química , Clotrimazol/análise , Centrifugação/métodos , Dióxido de Silício/química
2.
Food Chem ; 451: 139368, 2024 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-38657518

RESUMO

A unique strategy for developing porous membrane protected micro-solid phase extraction has been provided. An electrospun composite was fabricated on the sheet of membrane. To this end, NiFe-layered double hydroxide/Nylon 6 composite nanofibers were coated on a polypropylene membrane sheet followed by folding into a pocket shape, which were then utilized as a novel extractive device to extract of organophosphorus pesticides from fresh fruit juice samples prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The fabricated hybrid composites were successfully characterized. The effective parameters on extraction performance were investigated. LODs were 0.020-0.065 ng mL-1. Excellent linearity (R2≥0.996) was observed between 0.05 and 100.0 ng mL-1. RSDs% were in the range of 3.1-5.8% (intra-day, n = 3) and 2.6-5.5% (inter-day, n = 3×3). Satisfactory related recovery values within the acceptable range of 90.7-111.2% with RSDs% below 6.7% were achieved for the analysis of real samples.

3.
Anal Chim Acta ; 1287: 342127, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38182351

RESUMO

BACKGROUND: Considering that the brain controls most of the body's activities, it is very important to measure the factors affecting its function, such as dopamine and iodide. Due to the growing population in the world, it is necessary to provide fast, cheap and accurate methods with the capability of on-site analysis and without the need for invasive sampling and operator skill. As a result, there is a strong desire to replace laboratory instruments with small sensors for point-of-care testing. Paper-based analytical devices (PADs) are one of the popular zero-cost approaches to achieve this goal. RESULTS: We developed a simple and disposable diagnostic paper system based on electroanalytical and potential-power angle-based methods. First, we prepared an angle-based analytical system capable of performing semi-quantitative iodide analysis simply by reading the colored angle traveled. This system design is based on a channel containing complex reagents and two pencil-drawn electrodes to apply a constant voltage accelerating the anions migration. Meanwhile, a three-electrode system based on conductive pencil graphite is developed to measure dopamine concentration based on linear sweep voltammetry. For the quantitative analysis, the voltammetric data was wirelessly transmitted to a mobile device via Bluetooth communication. In this context, a power supply providing the required voltage for the migration of iodide ions, a portable potentiostat system, and a mobile application for measuring dopamine were developed. The calibration curves for I- and dopamine range from 3.5 × 10-4-47.0 × 10-4 and 10.0 × 10-6-1000.0 × 10-6 mol L-1 with LODs of 2.3 × 10-4 and 5.0 × 10-6 mol L-1, respectively. SIGNIFICANCE AND NOVELTY: A new portable dual-mode voltage-assisted integrated PAD platform was designed for iodide and dopamine analysis. The characteristics of this device allow non-experts to carry out in-field analysis using sub-100 µL saliva sample with a time-to-result of <10 min along with reducing the overall cost and operational complexity.


Assuntos
Aplicativos Móveis , Smartphone , Iodetos , Dopamina , Comunicação
5.
Mikrochim Acta ; 191(1): 10, 2023 12 06.
Artigo em Inglês | MEDLINE | ID: mdl-38052979

RESUMO

With a view to improving applicability as a sorbent while overcoming the challenges associated with its powdery nature, cobalt-doped zeolitic imidazolate framework (ZIF 67)-derived nanoporous carbon (Co-NPC) was employed as an additive in nanofiber through the process of electrospinning. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and Brunauer-Emmett-Teller (BET) surface area analysis were used to characterize the resulting nanocomposite. A microfluidic chip device with four layers, including two layers entailing spiral channels, was designed and employed to assess the analytical performance of the fabricated Co-NPC-reinforced electrospun composite. To do so, a folded piece of electrospun composite was sandwiched between two layers with spiral channels. Therefore, both sides of the folded composite acted as a sorptive phase to extract antifungal drugs as target analytes. The significant factors affecting the efficiency of the extraction process were investigated and optimized. Subsequently, the technique was verified through the utilization of liquid chromatography-tandem mass spectrometry (LC-MS/MS) by employing optimal parameters. The optimal conditions were applied to evaluate the figures of merit. A linear range was obtained for antifungal drugs within the range 0.25-200.0 ng ml-1 with an R2 value of ≥ 0.9914. The method demonstrated detection limits ranging between 0.08 and 0.40 ng ml-1. The intra-day and inter-day precisions were less than 6.9%. Relative recoveries exhibited variations between 91.4-106.8%, 95.9-103.6%, and 96.4-109.3% for ketoconazole, clotrimazole, and miconazole, respectively. The proposed approach yielded satisfactory results, demonstrating its efficiency.


Assuntos
Carbono , Nanofibras , Carbono/química , Cromatografia Líquida , Antifúngicos , Nanofibras/química , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Espectrometria de Massas em Tandem , Extração em Fase Sólida/métodos
6.
J Chromatogr A ; 1708: 464347, 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37696125

RESUMO

The current work presents an on-chip electromembrane extraction (OC-EME) method using deep eutectic solvent followed by QR code-based red-green-blue (RGB) analysis for measuring salicylic acid (SA) in plasma and pharmaceutical samples. The RGB analysis was performed based on forming the SA-Fe3+ complex in the acceptor phase giving a purple solution. The QR code readable customized app provided rapid, easy, and cost-less qualification and quantification of SA with the aid of principal component analysis (PCA). Parameters affecting OC-EME, including the supported liquid membrane (SLM), pH of the donor and acceptor phases, applied voltage, and sample flow rate, were optimized. Also, the concentration of FeCl3, as a chromogenic reagent, and its reaction time with SA were investigated to find the best concentration-dependent signal. Under the optimized conditions, a good relationship was observed between the green intensity and SA concentration within the range of 1.0-100.0 mg l-1 (R2 = 0.9946) in water and 5.0-100.0 mg l-1 (R2 = 0.9902) in plasma. Intra- and inter-day RSDs% were obtained less than 4.7% and 7.7%, respectively. Finally, the method was successfully applied for measuring SA in foot corn treatment, Aspirin medicines, and human plasma, with relative recoveries between 89.0 and 129.2%.


Assuntos
Ácido Salicílico , Smartphone , Humanos , Solventes , Solventes Eutéticos Profundos , Preparações Farmacêuticas
7.
J Chromatogr A ; 1702: 464080, 2023 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-37263055

RESUMO

In this work, electrospinning and hydrothermal methods were employed to synthesize an innovative 3D Co3O4/C@HCNFs nanocomposite as the sorbent. It was then used in a packed sorbent microextraction system for parabens analysis in human blood samples, followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The coaxial electrospun core-shell nanofibers mat was stabilized and carbonized to produce the hollow carbon nanofibers (HCNFs) substrate. A coating of cobalt carbonate hydroxide nanopolks was then grown on the HCNFs through hydrothermal synthesis. Ultimately, some of the nanopolks were converted to ZIF-67 by pouring the mat into a warm solution of 2-methyl imidazole and heat-treated into porous Co3O4/C afterward. X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) analyses were used to characterize the produced nanocomposite. The effective parameters of the adsorption and desorption steps were optimized by a central composite design. The figures of merit were evaluated under optimal conditions. The linear range of parabens was obtained between 0.5-500.0 ng ml-1 with R2 ≥ 0.9980. The detection limits of the method were between 0.1 and 0.2 ng ml-1. The intra-day and inter-day precisions were less than 4.3%. Relative recoveries between 92.0% and 109.3% were achieved. The findings demonstrated the eligible performance of the method.


Assuntos
Nanofibras , Microextração em Fase Sólida , Humanos , Microextração em Fase Sólida/métodos , Parabenos/análise , Carbono , Cromatografia Líquida , Nanofibras/química , Porosidade , Espectroscopia de Infravermelho com Transformada de Fourier , Espectrometria de Massas em Tandem , Cobalto
8.
Food Chem ; 414: 135667, 2023 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-36808032

RESUMO

A miniaturized on-chip electromembrane extraction device with QR code-based red-green-blue analysis was designed to determine copper in water, food, and soil. The acceptor droplet consisted of ascorbic acid as the reducing agent and bathocuproine as the chromogenic reagent. The formation of a yellowish-orange complex was a sign of copper in the sample. Then, the qualitative and quantitative analysis of the dried acceptor droplet was done by the customized Android app that was developed based on image analysis concepts. In this application, principal component analysis was performed on the data for the first time to reduce the three dimensions, red, green, and blue, to one dimension. The effective extraction parameters were optimized. The limit of detection and limit of quantification were 0.1 µg mL-1. Intra- and inter-assay relative standard deviations ranged between 2.0 and 2.3 % and 3.1-3.7 %, respectively. The calibration range was studied between 0.1 and 25 µg mL-1 (R2 = 0.9814).


Assuntos
Cobre , Alimentos , Membranas Artificiais
9.
Int J Biol Macromol ; 228: 426-434, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36563820

RESUMO

Milk adulteration analysis at different stages of the production chain, which profiteers widely use to mask milk quality parameters, is problematic. We prepared selective intelligent thin bio-films and a dedicated app to test milk adulteration in an out-of-lab setting. In this regard, each reagent is immobilized on a piece of starch/gelatin film as color-changeable polymeric support, which is then pasted onto a transparent test card. Incorporating starch and gelatin as the backbone of these composite films can significantly improve the mechanical properties, color, and potential applications in real-time monitoring. After 5 min floating of the card on the surface of the milk, our developed software as a Progressive Web Application can be used to locate and read the QR codes of the samples to estimate qualitative and quantitative information about the presence of some preservatives. These preservatives ranged from 0.1 to 200.0 mg/L, 1.0-100.0 mg/L, 0.001-0.05 mol/L in 10 mL of milk with the LODs of 0.1, 1.0 mg/L, and 0.001 mmol/L, for H2O2, Cr(VI), and salicylic acid, respectively. The pH monitoring film also indicates the freshness/spoilage of the milk. The portability, ease of use, and low cost of testing coupled with the app, make it an attractive alternative to lab-based analysis.


Assuntos
Colorimetria , Amido , Animais , Amido/química , Gelatina/química , Leite , Ligantes , Peróxido de Hidrogênio , Embalagem de Alimentos , Concentração de Íons de Hidrogênio , Antocianinas/química
10.
Food Chem ; 409: 135222, 2023 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-36586256

RESUMO

Herein, a novel homemade electrical device was designed, including two pieces of external neodymium magnets, providing a reciprocating magnetic field to introduce a magnetic-assisted dispersive pipette-tip micro solid-phase extraction. To evaluate the performance efficiency of the proposed method, a novel magnetic calcined GO/SiO2@Co-Fe nanocube sorbent was synthesized, filled into the pipette-tip, exposed to the reciprocating magnetic field, and applied for the preconcentration of some hormone therapy drugs in human biological matrices. The effective adsorption and desorption parameters were optimized using a rotatable central composite design and one-variable-at-a-time approaches. Under the optimized conditions, the target analytes' detection limits were found to be below 0.02 ng mL-1. Moreover, the calibration curves were linear in the range of 0.03-500.00 ng mL-1 (R2 > 0.9966), with RSDs% less than 7.8 %. Eventually, the established method was applied to extract the analytes from breast milk samples, followed by LC-ESI-MS/MS analysis.


Assuntos
Leite Humano , Espectrometria de Massas em Tandem , Feminino , Humanos , Espectrometria de Massas em Tandem/métodos , Dióxido de Silício , Cromatografia Líquida , Extração em Fase Sólida/métodos
11.
Anal Biochem ; 653: 114739, 2022 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-35644223

RESUMO

Here, four new sorbents based on dimethylglyoxime (DMG) functionalized silica-coated magnetic iron/graphene oxides (Fe3O4/MGO) were synthesized. A comparative study was performed among them to evaluate the different substrates and the role of the spacer in improving the lead extraction efficiency and selecting the most efficient sorbent. Based on experimental results, MGO@SiO2@3-chloropropyltrimethoxysilane@DMG was selected for magnetic dispersive µSPE of lead followed by flame (FAAS) and graphite furnace atomic absorption spectroscopy (GFAAS). The sorbents were characterized by FT-IR, FE-SEM, EDX, TEM, and Zeta potential. Sorbent amount (40.5 mg), sample pH (7.7), sonication time of adsorption and desorption procedures (9 min), and volume and acid concentration (2.2 mL of 2.7 mol L-1 nitric acid) were optimized using experimental design. Linearity of 20.0-600.0 ng mL-1 and 0.5-3.0 ng mL-1 resulted by FAAS and GFAAS, respectively. LODs were 7.0 and 0.2 ng mL-1 by FAAS and GFAAS, respectively. Intra- and inter-day RSDs% (n = 3) at two concentration levels of 3.0 and 100.0 ng mL-1 were below 7.6%.The adsorption capacity was 45.05 mg g-1. The adsorption isotherm showed a better fitting with the Langmuir model. Relative recoveries (%) of 87.8-115.1% were obtained for measuring trace amounts of lead in water, hair, and nail samples.


Assuntos
Grafite , Poluentes Químicos da Água , Adsorção , Grafite/química , Ferro/análise , Limite de Detecção , Óxido de Magnésio , Fenômenos Magnéticos , Óxidos/química , Oximas , Dióxido de Silício/química , Extração em Fase Sólida/métodos , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
12.
J Sep Sci ; 45(2): 594-601, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34714600

RESUMO

In the present research, a blended polyacrylamide-chitosan hydrogel was synthesized. For the first time, the prepared sorbent was efficiently employed in a hydrogel-based spin-column setup as a promising format. The proposed method was applied for monitoring the trace amounts of ketoconazole, clotrimazole, and miconazole in blood samples. Effective adsorption and desorption parameters were optimized using a central composite design and the one-variable-at-a-time method. Under the optimal conditions, the calibration curves were linear in the range of 15.0-1000.0, 1.0-1000.0, and 2.0-1000.0 ng mL-1 for ketoconazole, clotrimazole, and miconazole, respectively, along with intra- and interday precision less than 8.4%. Limits of detection were obtained between 0.2 and 5.0 ng mL-1 . The preconcentration factors were found in the range of 5.9-7.8. The introduced method was successfully applied for micro-solid-phase extraction of trace amounts of target antifungal drugs in blood samples, followed by liquid chromatography-tandem mass spectrometry. Satisfactory relative recoveries of 94.5-103.5% were obtained, implying method reliability. Overall, the proposed method provides good accuracy and repeatability, high reusability, and good applicability to determine antifungal drugs in complex biological matrices.


Assuntos
Antifúngicos , Espectrometria de Massas em Tandem , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida , Hidrogéis , Limite de Detecção , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
13.
Talanta ; 235: 122724, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517592

RESUMO

In this study, a sensitive solid phase microextraction (SPME) coating was developed based on two kinds of plugged and non-plugged bifunctional periodic mesoporous organosilicas (BFPMO) with ionic liquid and ethyl units. The extraction efficiency of all plugged and unplugged sorbents was investigated for the extraction of chlorophenols (CPs) in water and honey samples by emphasizing the effect of different physicochemical properties. The separation and determination of the CPs was performed by gas chromatography-mass spectrometry (GC-MS). The extraction results showed that plugged BFPMO coating exhibited outstanding enrichment ability for the extraction of CPs as model analytes with different polarities. This can be attributed to a valuable hydrophobic-hydrophilic balance in the mesochanels of the plugged BFPMO, which is the result of the combination of plug technology and bridged organic groups. Low limits of detection in the range of 5-70 ng L-1, wide linearity, and good reproducibility (RSD = 8.1-10.1 % for n = 6) under the optimized extraction conditions were achieved. Finally, the BFPMOs coated fiber was successfully used for determination of CPs in real water samples. The relative recoveries for the five CPs were in the range of 92.3-104.0 %, which proved the applicability of the method.


Assuntos
Clorofenóis , Poluentes Químicos da Água , Clorofenóis/análise , Cromatografia Gasosa-Espectrometria de Massas , Reprodutibilidade dos Testes , Microextração em Fase Sólida , Poluentes Químicos da Água/análise
14.
Food Chem ; 363: 130330, 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34157556

RESUMO

An online micro solid-phase extraction (online-µSPE) using electrospun nanofibers, as an efficient sorbent, was developed to extract chlorobenzenes (CBs) from paddy soil, agricultural wastewater, and food samples (fruit juices, vegetables, rice samples) followed by high performance liquid chromatography analysis. Electrospun nanofibers were fabricated using a nanocomposite containing polyacrylonitrile and Zn-metal organic framework 74 @graphene oxide (PAN/Zn-MOF-74@GO), and subsequently characterized. Under the optimal conditions, acceptable linearity was obtained in the range of 0.25-700.00 ng mL-1 for 1,2-dichlorobenzene (1,2-DCB) and 2.50-700.00 ng mL-1 for both 1,2,3-trichlorobenzene (1,2,3-TCB) and 1,2,4-trichlorobenzene (1,2,4-TCB) with determination coefficients ≥ 0.9991. The limits of detection ranged from 0.08 to 1.10 ng mL-1. The intra-day and inter-day single fiber and fiber to fiber relative standard deviations were observed in the range of 4.1%-9.5% and 5.8%-12.1%, respectively. The performance of this method was examined by determining the target analytes in the different spiked samples.


Assuntos
Nanocompostos , Água , Resinas Acrílicas , Clorobenzenos , Cromatografia Líquida de Alta Pressão , Limite de Detecção , Solo , Extração em Fase Sólida , Zinco
15.
Talanta ; 229: 122273, 2021 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-33838775

RESUMO

With the advent of nanotechnology and its development, there have been dramatic advances in various aspects of diverse sciences. Nanotechnology encompasses the manipulating matter to create nanometre-scale materials with prodigious features and their implementation in a vast range of applications. The topic that is the current debate in today's scientific community and the transformation origin in modern technologies. Magnetic nanomaterials belong to the group of materials mainly consisting of a magnetic component, such as iron, and a chemical functionality agent. Hitherto, several reports on these materials have been published in various sciences, including chemistry, and their applications have been discussed from different perspectives. One of the most interesting aspects of these materials is in a special type of chromatographic techniques, called "magnetic-chromatography" as well as "magneto-chromatography". The subject that has been somewhat underestimated compared to the other practical aspects of these materials. This review devotes to the recent issue and seeks to address the principles, benefits, challenges, analytical data, and potential applications of magnetic-chromatography in ions separation, size fractionation of magnetic nanoparticles, and isolation of biologically active organic molecules. Also, the new aspects and future trends of this technique are discussed.

16.
Food Chem ; 350: 129242, 2021 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-33626398

RESUMO

Herein, an electrospun polyacrylonitrile/nickel-based metal-organic framework nanocomposite (PAN/Ni-MOF) coating on a stainless steel wire was synthesized and employed as a novel nanosorbent for headspace solid-phase microextraction (HS-SPME) of organophosphorus pesticides (OPPs), diazinon (DIZ), and chlorpyrifos (CPS) from the diverse aqueous media followed by corona discharge ion mobility spectrometry (CD-IMS). Under the optimum experimental conditions, the calibration plots were linear in the range of 1.0-250.0 ng mL-1 for DIZ and 0.5-300.0 ng mL-1 for CPS with r2 > 0.999. The detection limits (S/N = 3) were 0.3 and 0.2 ng mL-1 for DIZ and CPS, respectively. The intra-day relative standard deviations (RSDs%) (n = 5) at the concentration levels of 20.0, 40.0, and 100.0 ng mL-1 were ≤ 5.2%. To investigate the extraction efficiency, PAN/Ni-MOF was employed to analyze various juice samples, including orange, apple, and grape juices, and in three water samples where it led to good recoveries ranged between 87% and 98%.


Assuntos
Clorpirifos/isolamento & purificação , Diazinon/isolamento & purificação , Espectrometria de Mobilidade Iônica/métodos , Estruturas Metalorgânicas/química , Nanofibras/química , Níquel/química , Praguicidas/isolamento & purificação , Microextração em Fase Sólida/métodos , Sucos de Frutas e Vegetais/análise , Limite de Detecção , Aço Inoxidável/análise , Aço Inoxidável/química
17.
Talanta ; 224: 121864, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33379075

RESUMO

In the present study, a versatile combination of electromembrane extraction (EME) with thin film solid phase microextraction (TF-SPME) was introduced using a microfluidic chip device. The device consisted of two single channels on two separate layers. The upper channel was dedicated to donor phase flow pass, while the beneath channel was used as a reservoir for stagnant acceptor solution. A slide of fluorine doped tin oxide (FTO) was accommodated in the bottom of the acceptor phase channel. A thin layer of polyaniline was electrodeposited on the FTO surface to achieve the required thin film for TF-SPME. A stainless-steel wire was embedded in the donor phase channel and another wire was also attached to the FTO surface. The channels were separated by a piece of polypropylene membrane impregnated with 1-octanol and the whole chip was fixed with bolts and nuts. The driving force for the extraction was an 8 V direct current (DC) voltage applied across the supported liquid membrane (SLM). Under the influence of the electrical field, analytes immigrated from sample towards the acceptor phase and then adsorbed on the thin film of the solid phase. Finally, the analytes were desorbed by successive movement of a desorption solvent in the acceptor phase channel followed by injection of the desorption solution to HPLC-UV. The applicability of the proposed device was demonstrated by the determination of four synthetic food dyes: Amaranth, Ponceau 4R, Allura Red, and Carmoisine, as the model analytes. The effective parameters on the efficiency of the both EME and TF-SPME were investigated. Under the optimized conditions, the microchip provided low LODs (1-10 µg L-1), and a wide linear dynamic range of 10-1000 µg L-1 for all analytes. The system also offered RSD values lower than 5.5% and acceptable reusability of the thin film for multiple extractions.

18.
Anal Biochem ; 612: 113949, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32941913

RESUMO

In this work, a nanocomposite of ZnCr layered double hydroxide (ZnCr LDH) and graphene oxide (GO) was successfully assembled. An efficient pipette-tip solid-phase extraction (PT-SPE) based on GO/ZnCr LDH followed by GFAAS analysis was used for to preconcentrate Pb(II) in hair samples. Hair samples were treated using acid digestion to make the solid samples suitable for performing the PT-SPE procedure and decrease the interactions between Pb(II) ions and the sample matrix. The sorbent was characterized by FT-IR, SEM, TEM, EDX, elemental mapping, and XRD. Effective extraction parameters were thoroughly investigated. Under the best conditions, the calibration plot was linear within the range of 0.5-15 ng mL-1 (R2 = 0.991). Preconcentration factor (PF) of 10 and absolute recovery (%) of 100% were obtained. LOD and LOQ were found to be 0.1 µg g-1 and 0.5 µg g-1, respectively. The intra-day and inter-day precisions (n = 3) at the concentrations of 2.0 and 10 ng mL-1 were less than 6.8% and 12.5%, respectively. Finally, the method efficiency was investigated for the analysis of Pb(II) in hair samples, and good relative recoveries (RR%) were obtained within the range of 92%-104%.


Assuntos
Compostos de Cromo/química , Grafite/química , Cabelo/química , Hidróxidos/química , Chumbo/análise , Extração em Fase Sólida/métodos , Espectrofotometria Atômica/métodos , Compostos de Zinco/química , Adsorção , Cátions/química , Limite de Detecção , Nanocompostos/química , Nanocompostos/ultraestrutura , Espectroscopia de Infravermelho com Transformada de Fourier
19.
Mikrochim Acta ; 187(10): 548, 2020 09 04.
Artigo em Inglês | MEDLINE | ID: mdl-32886213

RESUMO

For the first time, a fiber coating based on copper metal-organic framework was fabricated on an anodized stainless steel wire by an in situ electrosynthesis approach. The fiber was used for the preconcentration and determination of methamphetamine by headspace solid-phase microextraction followed by gas chromatography-flame ionization detection. The electrosynthesis of the fiber coating was performed under a constant potential of - 1.7 V by controlling the electrogeneration of OH- in a solution containing sodium nitrate as the probase, 1,2,4,5-benzenetetracarboxylate acid as the ligand and copper nitrate as the cation source. The coating was characterized using field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The effective parameters on the electrosynthesis, extraction, and desorption processes were thoroughly optimized. Under the optimized conditions, metamphetamine (MAP) was quantified over a linear range of 0.90-1000.0 ng mL-1 with R2 > 0.997. A limit of detection of 0.1 ng mL-1 was achieved, and intra- and inter-day relative standard deviations were found within the range 3.0-4.4% and 2.8-3.9%, respectively. Finally, the method was successfully applied to determination of MAP in urine samples with good recoveries in the range 85.0-102.5%. Graphical abstract Schematic representation of the in-situ electrochemical synthesis of a Cu-based metal-organic framework and its application in a headspace SPME procedure for the measuring methamphetamine in urine samples followed by GC-MS analysis.


Assuntos
Cobre/química , Eletroquímica/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Estruturas Metalorgânicas/química , Metanfetamina/urina , Microextração em Fase Sólida/métodos , Humanos , Metanfetamina/química
20.
Anal Chim Acta ; 1131: 90-101, 2020 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-32928484

RESUMO

Herein, we applied a simple electrosynthesis process to deposit nickel-iron layered double hydroxides (NiFe LDH) on the surface of copper hydroxide (Cu(OH)2) needle-shaped nanoarrays and introduce a new sorbent for thin-film solid phase microextraction (TF-SPME). For this purpose, the nanoarrays were grown via electrochemical anodization on a copper foil's surface and then modified with NiFe LDH. The synthesized sorbent was characterized by field emission-scanning electron microscopy, Brunauer-Emmett-Teller (BET), and Barrett-Joiner-Halenda (BJH) analysis, energy-dispersive X-ray spectroscopy, and X-ray diffraction. The Cu(OH)2-NiFe LDH based TF-SPME method was used to measure antifungal drugs in veterinary plasma samples followed by HPLC-UV analysis. The effects of various parameters in the extraction efficiency, including pH (5.0), extraction time (20 min), stirring rate (500 rpm), and salt effect (5.0%), type of eluent (acetonitrile), eluent volume (100 µL) and desorption time (5 min) were thoroughly optimized. Under the optimum conditions, limits of detection for ketoconazole, clotrimazole, and miconazole were obtained below 10 ng mL-1. Intra-day, inter-day and film-to-film RSDs% were obtained less than 6.2%, 7.3% and 7.0%, respectively. Moreover, calibration plots were linear from 30 to 5000 ng mL-1 for ketoconazole, 8.0-1000 ng mL-1 for clotrimazole, and 15-1000 ng mL-1 for miconazole, with determination coefficients between 0.9937 and 0.9971. Finally, good relative recoveries (%) in the range of 85-97% were obtained for measuring trace amounts of antifungal drugs in dogs' plasma samples. As a result, the method can be considered as an appropriate alternative to the conventional sample preparation methods for measuring trace amounts of antifungal drugs in biological samples.

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