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1.
Molecules ; 26(17)2021 Aug 27.
Artigo em Inglês | MEDLINE | ID: mdl-34500641

RESUMO

A novel diatomite-supported zeolitic imidazolate framework-8 sorbent (ZIF-8@Dt-COOH) was in situ fabricated and developed for solid-phase extraction of three benzodiazepines (triazolam, midazolam and diazepam) in urine followed by high-performance liquid chromatography. ZIF-8@Dt-COOH was easily prepared by coating ZIF-8 on the surface of Dt-COOH and characterized by Fourier transform infrared spectra, X-ray powder diffractometry and scanning electron microscopy. Compared with bare Dt-COOH, the extraction efficiency of ZIF-8@Dt-COOH for the target was significantly increased from 20.1-39.0% to 100%. Main extraction parameters, including ionic strength and pH of solution, loading volume, washing solution, elution solvent and elution volume, were optimized in detail. Under optimum conditions, the developed method gave linearity of three BZDs in 2-500 ng/mL (r ≥ 0.9995). Limits of detection (S/N = 3), and limits of quantification (S/N = 10) were 0.3-0.4 ng/mL and 1.0-1.3 ng/mL, respectively. In addition, the average recoveries at three spiked levels (5, 10 and 20 ng/mL) varied from 80.0% to 98.7%, with the intra-day and inter-day precisions of 1.4-5.2% and 1.5-8.2%, respectively. The proposed method provided an effective purification performance and gave the enrichment factors of 24.0-29.6. The proposed method was successfully employed for the accurate and sensitive determination of benzodiazepines in urine.


Assuntos
Benzodiazepinas/urina , Terra de Diatomáceas/química , Urina/química , Zeolitas/química , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Limite de Detecção , Extração em Fase Sólida/métodos , Soluções/química , Solventes/química
2.
Molecules ; 26(15)2021 Jul 29.
Artigo em Inglês | MEDLINE | ID: mdl-34361757

RESUMO

Detection of relevant contaminants using screening approaches is a key issue to ensure food safety and respect for the regulatory limits established. Electrochemical sensors present several advantages such as rapidity; ease of use; possibility of on-site analysis and low cost. The lack of selectivity for electrochemical sensors working in complex samples as food may be overcome by coupling them with molecularly imprinted polymers (MIPs). MIPs are synthetic materials that mimic biological receptors and are produced by the polymerization of functional monomers in presence of a target analyte. This paper critically reviews and discusses the recent progress in MIP-based electrochemical sensors for food safety. A brief introduction on MIPs and electrochemical sensors is given; followed by a discussion of the recent achievements for various MIPs-based electrochemical sensors for food contaminants analysis. Both electropolymerization and chemical synthesis of MIP-based electrochemical sensing are discussed as well as the relevant applications of MIPs used in sample preparation and then coupled to electrochemical analysis. Future perspectives and challenges have been eventually given.


Assuntos
Técnicas Biossensoriais , Técnicas Eletroquímicas , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Impressão Molecular/métodos , Polímeros Molecularmente Impressos/síntese química , Animais , Toxinas Bacterianas/análise , Análise de Alimentos/instrumentação , Inocuidade dos Alimentos/métodos , Humanos , Micotoxinas/análise , Praguicidas/análise , Polimerização , Extração em Fase Sólida/métodos , Drogas Veterinárias/análise
3.
Int J Mol Sci ; 22(16)2021 Aug 04.
Artigo em Inglês | MEDLINE | ID: mdl-34445079

RESUMO

Solid-phase extraction (SPE) coupled to LC/MS/MS analysis is a valid approach for the determination of organic micropollutants (OMPs) in liquid samples. To remove the greatest number of OMPs from environmental matrices, the development of innovative sorbent materials is crucial. Recently, much attention has been paid to inorganic nanosystems such as graphite-derived materials. Graphene oxide has been employed in water-purification processes, including the removal of several micropollutants such as dyes, flame retardants, or pharmaceutical products. Polysaccharides have also been widely used as convenient media for the dispersion of sorbent materials, thanks to their unique properties such as biodegradability, biocompatibility, nontoxicity, and low cost. In this work, chitosan-graphene oxide (CS_GO) composite membranes containing different amounts of GO were prepared and used as sorbents for the SPE of pesticides. To improve their dimensional stability in aqueous medium, the CS_GO membranes were surface crosslinked with glutaraldehyde. The composite systems were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, thermogravimetric analysis, swelling degree, contact angle, and mechanical measurements. As the GO content increased, a decrease in surface homogeneity, an improvement of mechanical properties, and a reduction of thermal stability of the CS-based membranes were observed. The increased dimensional stability in water, together with the presence of high GO amounts, made the prepared composite membranes more efficacious than the ones based just on CS in isolating and preconcentrating different hydrophilic/hydrophobic pollutants.


Assuntos
Quitosana/química , Grafite/química , Membranas Artificiais , Praguicidas/isolamento & purificação , Extração em Fase Sólida/instrumentação , Poluentes Químicos da Água/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Praguicidas/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem , Água/análise , Poluentes Químicos da Água/análise
4.
ACS Appl Mater Interfaces ; 13(33): 39905-39914, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34374514

RESUMO

The lack of functional groups or binding sites largely hindered the broad application of microporous organic networks (MONs). Herein, we report the fabrication of the sulfonate group-enriched magnetic MON composite (MMON-SO3H@SO3Na) via the combination of the sulfonic acid group containing the monomer and thiol-yne click postmodification for efficient magnetic solid-phase extraction (MSPE) of benzimidazole fungicides (BZDs) from complex sample matrices. The well-defined core-shell-structured MMON-SO3H@SO3Na was obtained and served as an advanced adsorbent for MSPE for concentrating and monitoring trace BZDs. The MMON-SO3H@SO3Na with numerous sulfonate groups provides plenty of ion-exchange, hydrogen-bonding, and π-π sites, leading to the favorable affinity to BZDs via multiple interaction mechanisms. The MMON-SO3H@SO3Na-based MSPE-high-performance liquid chromatography method afforded a wide linear range, low limits of detection, large enrichment factors, good precisions, and reusability for BZDs. Trace BZDs in complex vegetables and fruit samples were successfully detected by the established method. The MMON-SO3H@SO3Na also exhibited good selectivity toward multiple types of polar contaminants containing hydrogen-bonding sites and aromatic structures. This work provided a new postsynthesis strategy for constructing novel and multifunctioned magnetic MONs for preconcentration of trace analytes in a complex matrix.


Assuntos
Alcanossulfonatos/síntese química , Alcinos/química , Benzimidazóis/isolamento & purificação , Análise de Alimentos/métodos , Fungicidas Industriais/isolamento & purificação , Compostos de Sulfidrila/química , Cromatografia Líquida de Alta Pressão/métodos , Química Click , Óxido Ferroso-Férrico/química , Frutas/química , Limite de Detecção , Magnetismo/métodos , Microesferas , Porosidade , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos , Verduras/química
5.
Molecules ; 26(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207051

RESUMO

An ultra-high performance liquid chromatography coupled to tandem mass spectrometry method is proposed for the determination of the major ergot alkaloids (ergometrine, ergosine, ergotamine, ergocornine, ergokryptine, ergocristine) and their epimers (ergometrinine, ergosinine, ergotaminine, ergocorninine, ergokryptinine, and ergocristinine) in oat-based foods and food supplements. A modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) procedure was applied as sample treatment, reducing the consumption of organic solvent and increasing sensitivity. This method involved an extraction with acetonitrile and ammonium carbonate (85:15, v/v) and a clean-up step based on dispersive solid-phase extraction, employing a mixture of C18/Z-Sep+ as sorbents. Procedural calibration curves were established and limits of quantification were below 3.2 µg/kg for the studied compounds. Repeatability and intermediate precision (expressed as RSD%) were lower than 6.3% and 15%, respectively, with recoveries ranging between 89.7% and 109%. The method was applied to oat-based products (bran, flakes, flour, grass, hydroalcoholic extracts, juices, and tablets), finding a positive sample of oat bran contaminated with ergometrine, ergosine, ergometrinine, and ergosinine (total content of 10.7 µg/kg).


Assuntos
Avena/química , Alcaloides de Claviceps/química , Alimento Funcional/análise , Carbonatos/química , Cromatografia Líquida de Alta Pressão/métodos , Ergolinas/química , Ergonovina/química , Ergotaminas/química , Contaminação de Alimentos/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
6.
Molecules ; 26(12)2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208757

RESUMO

BACKGROUND: Pesticide residues are a threat to the health of the global population, not only to farmers, applicators, and other pesticide professionals. Humans are exposed through various routes such as food, skin, and inhalation. This study summarizes the different methods to assess and/or estimate human exposure to pesticide residues of the global population. METHODS: A systematic search was carried out on Scopus and web of science databases of studies on human exposure to pesticide residues since 2019. RESULTS: The methods to estimate human health risk can be categorized as direct (determining the exposure through specific biomarkers in human matrices) or indirect (determining the levels in the environment and food and estimating the occurrence). The role that analytical techniques play was analyzed. In both cases, the application of generic solvent extraction and solid-phase extraction (SPE) clean-up, followed by liquid or gas chromatography coupled to mass spectrometry, is decisive. Advances within the analytical techniques have played an unquestionable role. CONCLUSIONS: All these studies have contributed to an important advance in the knowledge of analytical techniques for the detection of pesticide levels and the subsequent assessment of nonoccupational human exposure.


Assuntos
Exposição Ambiental/análise , Resíduos de Praguicidas/efeitos adversos , Praguicidas/efeitos adversos , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Indicadores Básicos de Saúde , Humanos , Espectrometria de Massas/métodos , Resíduos de Praguicidas/análise , Praguicidas/análise , Extração em Fase Sólida/métodos , Solventes/química
7.
ACS Appl Mater Interfaces ; 13(24): 28424-28432, 2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34121386

RESUMO

Circumventing the impact of agrochemicals on aquatic environments has become a necessity for health and ecological reasons. Herein, we report the use of a family of five eco-friendly water-stable isoreticular metal-organic frameworks (MOFs), prepared from amino acids, as adsorbents for the removal of neonicotinoid insecticides (thiamethoxam, clothianidin, imidacloprid, acetamiprid, and thiacloprid) from water. Among them, the three MOFs containing thioether-based residues show remarkable removal efficiency. In particular, the novel multivariate MOF {SrIICuII6[(S,S)-methox]1.5[(S,S)-Mecysmox]1.50(OH)2(H2O)}·36H2O (5), featuring narrow functional channels decorated with both -CH2SCH3 and -CH2CH2SCH3 thioalkyl chains-from l-methionine and l-methylcysteine amino acid-derived ligands, respectively-stands out and exhibits the higher removal efficiency, being capable to capture 100% of acetamiprid and thiacloprid in a single capture step under dynamic solid-phase extraction conditions-less than 30 s. Such unusual combination of outstanding efficiency, high stability in environmental conditions, and low-cost straightforward synthesis in 5 places this material among the most attractive adsorbents reported for the removal of this type of contaminants.


Assuntos
Inseticidas/isolamento & purificação , Estruturas Metalorgânicas/química , Neonicotinoides/isolamento & purificação , Sulfetos/química , Poluentes Químicos da Água/isolamento & purificação , Adsorção , Cisteína/análogos & derivados , Cisteína/química , Inseticidas/química , Metionina/química , Neonicotinoides/química , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/química , Purificação da Água/métodos
8.
Molecules ; 26(9)2021 May 02.
Artigo em Inglês | MEDLINE | ID: mdl-34063259

RESUMO

In this study, we combine magnetic solid phase extraction (MSPE), with the screen-printed carbon electrode (SPCE) modified by a molecular imprinted polymer (MIP) for sensitive and selective extraction and electrochemical determination of Rhodamine B in food samples. A magnetic solid phase extraction (MSPE) was carried out using magnetic poly(styrene-co-divinylbenzene) (PS-DVB) and magnetic nanoparticles (MNPs) synthetized on the surface of multiwalled carbon nanotubes (MWCNTs). An MIP was prepared on the surface of MWCNTs in the presence of titanium oxide nanoparticles (TiO2NPs) modifying the SPCE for the rapid electrochemical detection of Rhodamine B. The MIPs synthesis was optimized by varying the activated titanium oxide (TiO2) and multiwalled carbon nanotubes (MWCNTs) amounts. The MSPE and electrochemical detection conditions were optimized as well. The present method exhibited good selectivity, high sensitivity, and good reproducibility towards the determination of Rhodamine B, making it a suitable method for the determination of Rhodamine B in food samples.


Assuntos
Análise de Alimentos/métodos , Nanotubos de Carbono/química , Polímeros/química , Rodaminas/análise , Adsorção , Técnicas Eletroquímicas , Eletrodos , Concentração de Íons de Hidrogênio , Limite de Detecção , Magnetismo , Microscopia Eletrônica de Varredura , Impressão Molecular , Polímeros Molecularmente Impressos , Poliestirenos/química , Reprodutibilidade dos Testes , Espalhamento de Radiação , Sensibilidade e Especificidade , Extração em Fase Sólida/métodos , Análise Espectral Raman , Titânio/química
9.
Molecules ; 26(9)2021 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-34065150

RESUMO

Bioanalysis is the scientific field of the quantitative determination of xenobiotics (e.g., drugs and their metabolites) and biotics (e.g., macromolecules) in biological matrices. The most common samples in bioanalysis include blood (i.e., serum, plasma and whole blood) and urine. However, the analysis of alternative biosamples, such as hair and nails are gaining more and more attention. The main limitations for the determination of small organic compounds in biological samples is their low concentration in these matrices, in combination with the sample complexity. Therefore, a sample preparation/analyte preconcentration step is typically required. Currently, the development of novel microextraction and miniaturized extraction techniques, as well as novel adsorbents for the analysis of biosamples, in compliance with the requirements of Green Analytical Chemistry, is in the forefront of research in analytical chemistry. Graphene oxide (GO) is undoubtedly a powerful adsorbent for sample preparation that has been successfully coupled with a plethora of green extraction techniques. GO is composed of carbon atoms in a sp2 single-atom layer of a hybrid connection, and it exhibits high surface area, as well as good mechanical and thermal stability. In this review, we aim to discuss the applications of GO and functionalized GO derivatives in microextraction and miniaturized extraction techniques for the determination of small organic molecules in biological samples.


Assuntos
Grafite/química , Química Verde , Compostos Orgânicos/química , Extração em Fase Sólida/métodos , Adsorção , Carbono/química , Humanos , Magnetismo , Polímeros Molecularmente Impressos , Nanomedicina , Nanoestruturas , Reprodutibilidade dos Testes , Propriedades de Superfície
10.
J Chromatogr A ; 1651: 462286, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34090056

RESUMO

The widespread use of quinolones has become an increasing global public health threat. In this study, IRMOF-3 coated SiO2/Fe3O4 were prepared via a facile room-temperature method. The prepared IRMOF-3 coated SiO2/Fe3O4 was used as a sorbent for magnetic solid phase extraction, and then combined with high-performance liquid chromatography-tandem mass spectrometry for the determination of 10 quinolines. The extraction conditions of magnetic solid phase extraction were studied in detail, and the optimal conditions were established. Under the optimal experimental conditions, the limits of quantification of 10 quinolones were in the range of 0.005-0.01 µg L-1, the relative standard deviations were 6.58-10.6% (n=7), the enrichment factors were 21.0-23.8 for water samples. The limits of quantification of 10 quinolones were in the range of 0.10-0.20 µg kg-1, the relative standard deviations were 5.95-14.5% (n=7), the enrichment factors were 1.08-1.24 for fish samples. The proposed method was applied for the determination of 10 quinolones in river water, aquacultural water and a fish sample, and enrofloxacin and ciprofloxacin were found in the fish sample.


Assuntos
Monitoramento Ambiental , Peixes/metabolismo , Fenômenos Magnéticos , Estruturas Metalorgânicas/química , Quinolonas/análise , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/análise , Adsorção , Animais , Cromatografia Líquida de Alta Pressão , Concentração de Íons de Hidrogênio , Concentração Osmolar , Reprodutibilidade dos Testes , Dióxido de Silício/química
11.
Methods Mol Biol ; 2326: 289-299, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34097277

RESUMO

Pesticides has become an essential part of our life and have entered and bioaccumulated in water, air, soil ecosystem, and food. However, the majority of the pesticides are not biodegradable and eco-friendly, and the accumulation of them in food and the ecosystem could constitute a serious risk to human and environmental health. It is critical to understand pesticides' identities and level of residues present in environment and food. Robust analytical techniques that offer easy, fast, and reliable extraction of multiresidue pesticides in water, soil and food with matrix interference-free quantification are necessary for proper risk assessment. Although various methods have been reported for pesticides extraction in food and environment samples, dispersive solid-phase extraction (d-SPE) has become the most popular sample preparation method for pesticides analysis today. Multiresidue pesticides extraction in food and environmental sample using a novel d-SPE method, dispersive pipette extraction (DPX), is described step-by-step in this chapter.


Assuntos
Contaminação de Alimentos/análise , Praguicidas/isolamento & purificação , Extração em Fase Sólida/métodos , Poluentes Químicos da Água/isolamento & purificação , Água/análise , Grão Comestível/química , Alimentos , Análise de Alimentos/métodos , Frutas/química , Verduras/química
12.
Artigo em Inglês | MEDLINE | ID: mdl-34098181

RESUMO

Nonylphenol (NP) is an endocrine disrupting and ecotoxic substance that has been detected in a variety of environmental matrices. It is utilized for the production of non-ionic nonylphenol ethoxylate (NPEO) detergents and other high production volume chemicals. Human biomonitoring data are scarce and mostly limited to the non-oxidized NP, which is ubiquitous in the (laboratory) environment and susceptible to external contamination. Here, we describe a sensitive, precise, accurate and rugged analytical method for the determination of OH-NP and oxo-NP, two potential alkyl-chain-oxidized metabolites of NP in human urine. We used single isomer standards, obtained by custom synthesis, for the quantification of the sum of the respective isomers. After enzymatic hydrolysis of potential urinary phase II conjugates, urine samples were analyzed by online turbulent flow chromatography for analyte enrichment and matrix depletion coupled to reversed phase liquid chromatography with negative electrospray-ionization triple quadrupole tandem mass spectrometry detection (online-SPE-LC-MS/MS). Quantification was performed by stable isotope dilution analysis. Limits of quantification in urinary matrix were 0.5 µg/L for OH-NP and 0.25 µg/L for oxo-NP. Mean relative recoveries were 101-105% (OH-NP) and 112-117% (oxo-NP) and the method imprecision (CV) in matrix was below 5%. In spite of extensive use restrictions in the EU since 2003, we could quantify OH-NP and oxo-NP in 94% and 47% of spot urine samples from the general German population (n = 32) collected in 2014. Thus, both metabolites seem suitable as sensitive and specific urinary biomarkers of NP exposure for future human biomonitoring population studies. Currently this method is used to quantitatively investigate human NP metabolism and to derive urinary metabolite excretion fractions that can be used to calculate external doses based on urinary biomarker concentrations.


Assuntos
Cromatografia Líquida/métodos , Fenóis/urina , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Adulto , Biomarcadores/urina , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
13.
Food Chem ; 362: 130214, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34082293

RESUMO

The ionic covalent organic framework (TPB-BFBIm-iCOF) was facilely synthetized by the size-controllable confinement method and chosen as the online solid phase extraction (SPE) adsorbent. This adsorbent showed fast adsorption equilibrium (5 min) and high adsorption capacity (87.7-140.8 mg g-1) for the per- and polyfluorinated alkyl substances (PFASs). The TPB-BFBIm-iCOF microsphere revealed the satisfactory enrichment performance for PFASs by means of the electrostatic interaction, hydrophobic effect and ordered channel structure. After extraction, the loaded TPB-BFBIm-iCOF-online SPE column was eluted and applied to the ultrahigh performance liquid chromatography tandem mass spectrometry analysis. Under the optimum conditions, the method displayed satisfactory linearity (R2 ≥ 0.9910) and low limits of detection (≤0.0017 ng g-1) for five seafoods. The relative recoveries of PFASs were 85.3%-109.4% with the relative standard deviation ≤ 9.9%. The method exhibited potential value in monitoring the toxicokinetics and environmental behaviors of PFASs.


Assuntos
Contaminação de Alimentos/análise , Hidrocarbonetos Fluorados/análise , Alimentos Marinhos/análise , Extração em Fase Sólida/métodos , Adsorção , Cromatografia Líquida de Alta Pressão/métodos , Teoria da Densidade Funcional , Análise de Alimentos/métodos , Hidrocarbonetos Fluorados/química , Limite de Detecção , Espectrometria de Massas em Tandem/métodos
14.
J Chromatogr A ; 1651: 462301, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34107399

RESUMO

In this work, a core-shell structured magnetic covalent organic framework named as M-TpDAB was constructed with 3,3'-diaminobenzidine (DAB) and 1,3,5-triformylphloroglucinol (Tp) as building units. M-TpDAB was characterized by infrared spectroscopy, nitrogen adsorption-desorption isotherms, powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. Using the M-TpDAB as adsorbent, a simple and highly effective method was proposed for preconcentrating phenylurea herbicides before high performance liquid-phase chromatography analysis. In the optimized conditions, a good linearity was achieved within the range of 0.15-100 ng mL-1 for water sample, 1.0-100.0 ng mL-1 for tea drink samples. The limits of detection for the analytes were 0.05-0.15 ng mL-1 for water sample and 0.30-0.50 ng mL-1 for drink samples. Satisfactory recoveries of spiked target compounds were in the range of 84.6%-105% for water sample and 80.3%-102% for tea drink samples. Finally, the M-TpDAB based method was successfully used to determine phenylurea herbicides in tea drinks and water samples, demonstrating a good alternative for analyzing trace level of phenylurea herbicides in water samples.


Assuntos
Herbicidas/isolamento & purificação , Estruturas Metalorgânicas/química , Compostos de Fenilureia/isolamento & purificação , Extração em Fase Sólida/métodos , Água/química , Adsorção , Cromatografia Líquida de Alta Pressão , Água Potável/química , Herbicidas/análise , Fenômenos Magnéticos , Magnetismo/métodos , Compostos de Fenilureia/análise , Difração de Raios X
15.
J Chromatogr A ; 1651: 462347, 2021 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-34166861

RESUMO

Herein, we report the fabrication of a novel, well-defined core-double-shell-structured magnetic Fe3O4@polydopamine@naphthyl microporous organic network (MON), Fe3O4@PDA@NMON, for the efficient magnetic extraction of hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and p-nitrophenol (p-Npn) from wastewater samples. The hierarchical nanospheres were designed and constructed with the Fe3O4 nanoparticle core, the inner shell of a polydopamine (PDA) layer, and the outer shell of a porous naphthyl MON (NMON) coating, allowing efficient and synergistic extraction of OH-PAHs and p-Npn via hydrophobic, hydrogen bonding, and π-π interactions. The Fe3O4@PDA@NMON nanospheres were well characterized and employed as an efficient sorbent for magnetic solid-phase extraction (MSPE) coupled with high performance liquid chromatography (HPLC) for analyzing of OH-PAHs and p-Npn. Under optimal conditions, the Fe3O4@PDA@NMON-based-MSPE-HPLC-UV method afforded wide linear range (0.18-500 µg L-1), low limits of detection (0.070 µg L-1 for p-Npn, 0.090 µg L-1 for 2-OH-Nap, 0.090 µg L-1 for 9-OH-Fluo and 0.055 µg L-1 for 9-OH-Phe, respectively), large enrichment factors (92.6-98.4), good precisions (intra-day and inter-day relative standard deviations (RSDs); <6.4%, n=6) and less consumption of the adsorbent. Furthermore, trace OH-PAHs and p-Npn with concentrations of 0.29-0.80 µg L-1 were successfully detected in various wastewater samples. Fe3O4@PDA@NMON also functioned as a good adsorbent to enrich a wide scope of trace contaminants containing hydrogen bonding sites and aromatic structures, highlighting the potential of functional MONs in sample pretreatment.


Assuntos
Indóis/química , Nanosferas/química , Nitrofenóis/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Polímeros/química , Extração em Fase Sólida/métodos , Águas Residuárias/química , Cromatografia Líquida de Alta Pressão , Interações Hidrofóbicas e Hidrofílicas , Limite de Detecção , Fenômenos Magnéticos , Nitrofenóis/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Porosidade
16.
J Chromatogr A ; 1648: 462192, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-33984649

RESUMO

Determination of folic acid and riboflavin in biological samples is difficult due to their high polarity, low concentration, chemical instability, and complex matrix. In this study, the polypyrrole-coated magnetic nanocomposite (Fe3O4@PPy) was synthesized innovatively with the assistance of hexadecyltrimethylammonium bromide. To evaluate the adsorption mechanism and the feasibility of synthesized Fe3O4@PPy as an adsorbent, the adsorption capacities, kinetics and thermodynamics of folic acid and riboflavin were investigated systemically. Furthermore, in light of the chemical instability of folic acid and riboflavin a method for rapid extraction and detection of them from human urine within 10 min was developed successfully by combining magnetic solid phase extraction with ultra-performance liquid chromatography (MSPE/UPLC). The adsorption parameters including sorbent amount, pH value, extraction time, desorption solvent and desorption time were studied. Under optimum conditions, the performance of the established determination method was validated with the linearly dependent coefficients (>0.9995), the limits of detection (0.02-0.05 µg/mL), the limits of quantification (0.07-0.18 µg/mL), and the recoveries (92.2-105.1%, with relative standard deviation < 3.3%). The rapid extraction and detection of folic acid and riboflavin from real urine samples were achieved subsequently. The present study suggests that the developed method exhibits a promising application in the analysis of free folic acid and riboflavin in human urine samples, which can provide a reference for the clinical drug monitoring and treatment.


Assuntos
Cromatografia Líquida/métodos , Ácido Fólico/urina , Magnetismo/métodos , Polímeros/química , Pirróis/química , Riboflavina/urina , Extração em Fase Sólida/métodos , Adsorção , Humanos , Limite de Detecção , Nanocompostos/química , Solventes/química
17.
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
18.
J Chromatogr A ; 1648: 462215, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34000593

RESUMO

A new analyte separation and preconcentration method for the trace determination of antidepressant drugs, Fluoxetine (FLU) and Citalopram (CIT) in urine and wastewaters, was developed based on HPLC-DAD analysis after magnetic solid phase extraction (MSPE). In the proposed method, FLU and CIT were retained on the newly synthetized magnetic sorbent (Fe3O4@PPy-GO) in the presence of buffer (pH 10.0) and then were desorbed into a lower volume of acetonitrile prior to the chromatographic determinations. Before HPLC analysis, all samples were filtered through a 0.45 µm PTFE filter. Experimental parameters such as interaction time, desorption solvent and volume, and pH were studied and optimized in order to establish the detection limit, linearity, enrichment factor and other analytical figures of merit under optimum operation conditions. In the developed method, FLU and CIT were analyzed by diode array detector at the corresponding maximum wavelengths of 227 and 238 nm, respectively, by using an isocratic elution of 60% pH 3.0 buffer, 30% acetonitrile, and 10% methanol. By using the optimum conditions, limit of detections for FLU and CIT were 1.58 and 1.43 ng mL-1, respectively, while the limit of quantifications was 4.82 and 4.71 ng mL-1, respectively. Relative standard deviations (RSD%) for triplicate analyses of model solutions containing 100 ng mL-1 target molecules were found to be less than 5.0 %. Finally, the method was successfully applied to urine (both simulated and real healthy human) and wastewater samples, and quantitative results were obtained in recovery experiments.


Assuntos
Antidepressivos/análise , Cromatografia Líquida/métodos , Citalopram/análise , Fluoxetina/análise , Espectrofotometria Ultravioleta/métodos , Águas Residuárias/química , Poluentes Químicos da Água/análise , Antidepressivos/urina , Citalopram/urina , Fluoxetina/urina , Humanos , Limite de Detecção , Extração em Fase Sólida/métodos , Solventes/química , Poluentes Químicos da Água/urina
19.
J Chromatogr A ; 1648: 462208, 2021 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-34000594

RESUMO

Public exposure to pesticides through tobacco has attracted serious attention. Here we report a simultaneous screening and quantitation method for the non-target multiresidue analysis of pesticides in different tobacco types. The method involved extraction of a homogenate (20 g, containing 2 g tobacco) in ethyl acetate (10 mL), cleanup of 2 mL extract by dispersive solid phase extraction with PSA (50 mg)+C18 (50 mg)+GCB (25 mg)+MgSO4 (100 mg), followed by reconstitution in 1 mL acetonitrile:water (3:7) and analysis using HPLC with Quadrupole-Orbitrap mass spectrometry. The high resolution accurate mass analysis was performed through sequential full-scan (resolution=35000) and variable data independent acquisition (resolution=17500) events. When the method was evaluated in a mixture of 181 pesticides, it effectively minimised matrix interferences and false negatives. The target compounds included 5 pairs of isomers and 27 pairs of isobars, which were distinguished based on chromatographic separation, mass resolving power and/or unique product ions. The screening detection limit (SDL) for 86.4% of the test pesticides was set at 5 ng/g, while the remainder had the SDLs at 10 ng/g (9.3%) and 40 ng/g (4.3%). Nearly, 75% of the compounds showed recoveries of 70-120% at 10 ng/g. The rest of the compounds showed satisfactory recoveries at 40 and 100 ng/g. In all cases, precision-RSDs were < 20%. The established method demonstrated a successful performance in four different types of tobacco matrices while aligning with the guidelines of SANTE and US-FDA. Owing to its efficiency, the method is recommended for screening and quantitation of multiclass pesticides in tobacco.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Resíduos de Praguicidas/análise , Espectrometria de Massas em Tandem/métodos , Tabaco/química , Limite de Detecção , Praguicidas/análise , Extração em Fase Sólida/métodos , Produtos do Tabaco/análise
20.
Food Chem ; 361: 130018, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34023690

RESUMO

Developing and establishing an efficient pre-treatment approach for the precise extraction of nitrated-polycyclic aromatic hydrocarbons (N-PAHs) from real-life samples is critical for ensuring their safety. In this study, a novel crystalline magnetic covalent organic framework with a grapevine structure not a single core-shell, Fe3O4@TAPT-DMTA-COF, was fabricated via chemical bonding. Unchanging the reticulated structure and high crystallinity of TAPT-DMTA-COF, the combination made this material possess not only simple operation via magnetic decantation but also remarkable chemical stability. Fe3O4@TAPT-DMTA-COF had a large surface area (1578.45 m2/g), and rich electronegative triazine-groups, which makes it become a superior magnetic enrichment material for trace N-PAHs. For N-PAHs analysis, low limits of detection (LODs) (1.43-17.24 ng/L), excellent relative standard deviations (RSDs ≤ 11.52%), and wide linearity (10-5000 ng/L) were obtained. Real-life applications based on this composite have been successfully explored by capturing the N-PAHs emitted from food and environmental samples.


Assuntos
Análise de Alimentos/métodos , Estruturas Metalorgânicas/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Extração em Fase Sólida/métodos , Café/química , Teoria da Densidade Funcional , Análise de Alimentos/instrumentação , Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Nanopartículas de Magnetita/química , Produtos da Carne/análise , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Sensibilidade e Especificidade , Extração em Fase Sólida/instrumentação , Triazinas/química , Poluentes Químicos da Água/análise
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