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1.
Anal Chim Acta ; 1178: 338849, 2021 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-34482875

RESUMO

Various mesoporous adsorbents are of great promise for enriching small molecules from biological samples based on the size-exclusion effect. At present, the mesoporous adsorbents have adsorption sites distributed uniformly on the internal and external surfaces of mesopores. However, the adsorption sites on the external surface can adsorb proteins, interfering with the enrichment of small molecules. Herein, a novel immobilized-Ti4+ magnetic mesoporous adsorbent removing the adsorption sites on the external surface was facile prepared via the coupling chemistry of isocyanate with amine and consequent hydrolysis of urea linkage by urease. The adsorbent enables fast and selective enrichment of phosphopeptides and nucleotides from biological samples. In addition, sensitive detection methods for phosphopeptides and nucleotides in human serum are developed by coupling the magnetic solid-phase extraction with matrix-assisted laser desorption/ionization time of flight mass spectrometry and liquid chromatography-mass spectrometer, respectively. Under optimal conditions, response is linear (R2 ≥ 0.9923), limits of detection are low (0.41-9.48 ng mL-1), and reproducibility is acceptable (inter- and intra-day assay RSDs of≤15.0%) for six nucleotides. The developed strategy offers an effective method to eliminate the interference of proteins in the enrichment of small molecules from real biological samples.


Assuntos
Nucleotídeos , Fosfopeptídeos , Adsorção , Humanos , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
2.
J Colloid Interface Sci ; 586: 683-691, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33223238

RESUMO

As an important biomarker, the analysis of cytochrome c (Cyt c) plays a crucial role in cell-apoptosis or even cancer diagnosis. This work develops a label-free probe for Cyt c using the nitrogen and fluorine co-doped carbon dots (N, F-CDs) which were facile prepared through solvothermal method with 3, 4-difluorophenylhydrazine as precursor. The N, F-CDs have an average diameter of 3.4 nm, and can form a quite stable colloidal solution. The N, F-CDs show bright yellow-green fluorescence, excitation/emission wavelengths 475/530 nm, and a relatively high fluorescence quantum yield of 16.9%. Interestingly, the N, F-CDs indicate a linear and reversible variation of emission intensity with a sensitivity of -1.11% per ℃ in the temperature range from 25 to 60 ℃. Inner filter effect (IFE) between N, F-CDs and Cyt c turns the fluorescence of N, F-CDs from "on" to "off". The sensor possesses the excellent anti-interference ability towards the main components of plasma. Under optimum conditions, there is a linear relationship between fluorescence intensity function (F0-F) and the concentration of Cyt c in the range of 0.5-25 µΜ with a limit of detection (LOD) (S/N = 3) of 0.25 µM. Finally, the developed method has been successfully used to detect Cyt c in human serum sample with satisfactory recoveries in a range of 93.14-110.40%.


Assuntos
Citocromos c , Pontos Quânticos , Carbono , Flúor , Humanos , Nitrogênio , Temperatura
3.
Mikrochim Acta ; 187(8): 472, 2020 07 29.
Artigo em Inglês | MEDLINE | ID: mdl-32725323

RESUMO

An immobilized metal affinity (IMA) adsorbent was prepared by grafting bottlebrush polymer pendant with iminodiacetic acid (IDA) from the surface of polydopamine (PDA)-coated magnetic graphene oxide (magGO), via surface-initiated atom transfer radical polymerization (SI-ATRP). Poly(hydroxyethyl methacrylate) (PHEMA) was grafted firstly from the PDA-coated magGO as the backbone, and then poly(glycidyl methacrylate) was grafted from the PHEMA chains via the second SI-ATRP to afford the bottlebrush polymer-grafted magGO Thereafter, IDA was anchored on the nanocomposites to produce the IMA adsorbent after chelating copper ions. The adsorbent was characterized by various physical and physicochemical methods. Its adsorption properties were evaluated by using histidine-rich proteins (bovine hemoglobin, BHb) and other proteins (lysozyme and cytochrome-C). The results show that its maximum adsorption capacity to BHb was 378.6 mg g-1, and the adsorption equilibrium can be quickly reached within 1 h. The adsorbent has excellent reproducibility and reusability. It has been applied to selectively purify hemoglobin from human whole blood, indicating its potential in practical applications. Graphical abstract.


Assuntos
Grafite/química , Hemoglobinas/isolamento & purificação , Adsorção , Animais , Bovinos , Cobre/química , Humanos , Iminoácidos/química , Indóis/química , Extração Líquido-Líquido/métodos , Fenômenos Magnéticos , Poli-Hidroxietil Metacrilato/química , Polímeros/química , Ácidos Polimetacrílicos/química , Reprodutibilidade dos Testes
4.
J Sep Sci ; 43(15): 3110-3119, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32468707

RESUMO

Graphene oxide has received extensive attention because of its unique properties and potential applications. In this study, magnetic nitrogen-doped graphene was prepared by one-step hydrothermal reaction using urea as the dopant and reductant, and ferroferric oxide nanoparticles were in situ deposited on the surface of the nanohybrids. The magnetic nitrogen-doped graphene was characterized using various physical and chemical methods. It was used as a new adsorbent for the magnetic solid-phase extraction of four nonsteroidal anti-inflammatory drugs from the river water. The parameters influencing the extraction efficiency were optimized in detail. Under optimal conditions, this method provided a wide linear range (5-200 ng/mL). The limits of detection were in the range of 1.07-5.10 ng/mL. The recoveries varied from 81.2 to 121.5% with relative standard deviations of less than 10.8%. Overall, we can conclude that the proposed method offers an efficient pretreatment and enrichment and can be successfully applied for the extraction and determination of nonsteroidal anti-inflammatory drugs in complex matrices.


Assuntos
Anti-Inflamatórios não Esteroides/análise , Grafite/química , Nitrogênio/química , Extração em Fase Sólida , Temperatura , Poluentes Químicos da Água/análise , Fenômenos Magnéticos , Estrutura Molecular , Tamanho da Partícula , Propriedades de Superfície
5.
J Sep Sci ; 43(14): 2766-2772, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32419326

RESUMO

Poly(ionic liquid)-modified stationary phases can have multiple interactions with solutes. However, in most stationary phases, separation selectivity is adjusted by changing the poly(ionic liquid) anions. In this work, two poly(ionic liquid)-modified silica stationary phases were prepared by introducing the cyano or tetrazolyl group on the pendant imidazolium cation on the polymer chains. Various analytes were selected to investigate their mechanism of retention in the stationary phases using different mobile phases. Two poly(ionic liquid)-modified stationary phases can provide various interactions toward solutes. Compared to the cyano-functionalized poly(ionic liquid) stationary phase, the tetrazolyl-functionalized poly(ionic liquid) stationary phase provides additional cation-exchange and π-π interactions, resulting in different separation selectivity toward analytes. Finally, applicability of the developed stationary phases was demonstrated by the efficient separation of nonsteroidal anti-inflammatory drugs.

6.
Anal Chim Acta ; 1093: 61-74, 2020 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-31735216

RESUMO

Covalent organic frameworks (COFs) have been increasingly employed in separation science, including sample preparation. Herein we fabricated the amino bearing core-shell structured COFs nanospheres [Fe3O4@TpBD(NH2)2], and a novel magnetic boronate affinity adsorbent was synthesized by postsynthetic modification of the Fe3O4@TpBD(NH2)2 with 2-formylphenylboronic acid. The magnetic boronate affinity adsorbent possesses fast magnetic response and high binding capacity up to 1037 µmol g-1 for dopamine. Besides, it was used as an adsorbent for extraction of urinary monoamine neurotransmitters at neutral pH. A method for detection of the monoamine neurotransmitters was developed by coupling the magnetic solid phase extraction with high-performance liquid chromatography-fluorescence detection. Under the optimized conditions, a good analytical method was obtained in the linear dynamic range of 2-200 ng mL-1 with R2 between 0.9917 and 0.9966, with low limit of detection (0.31-0.54 ng mL-1) and limit of quantification (1.04-1.80 ng mL-1). The recoveries of the monoamine neurotransmitters were in the range of 86.3-115%, with relative standard deviations of 2.34-10.5% (intra-day) and 2.84-14.4% (inter-day). The method was successfully applied to the determination of the monoamine neurotransmitters in human urine samples. This work is of great importance for preparing functionalized core-shell structured magnetic covalent organic framework nanospheres, it also demonstrates the feasibility of the functionalized magnetic COFs as adsorbents in sample pretreatment.


Assuntos
Monoaminas Biogênicas/urina , Ácidos Borônicos/química , Catecolaminas/urina , Estruturas Metalorgânicas/química , Nanosferas/química , Neurotransmissores/urina , Adsorção , Cromatografia Líquida de Alta Pressão/métodos , Humanos , Limite de Detecção , Nanopartículas de Magnetita/química , Estruturas Metalorgânicas/síntese química , Porosidade , Reprodutibilidade dos Testes , Extração em Fase Sólida/métodos
7.
Se Pu ; 38(4): 424-429, 2020 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-34213224

RESUMO

A novel mixed-mode chromatographic stationary phase was prepared via surface initiated atom transfer radical polymerization using an imidazole side-group functionalized ionic liquid monomer, 1-(4-vinylbenzyl)-3-cyanomethyl bromide. The structure of the stationary phase was characterized by infrared spectroscopy, elemental analysis, and thermogravimetric analysis. The stationary phase showed good separation ability. The retention mechanism of reversed-phase/ion exchange toward solutes on the stationary phase was verified by determining the effect of mobile phase pH on the retention of substances. Compared with octadecylsilyl-bonded silica stationary phase, it is confirmed that the poly(ionic liquid)-modified stationary phase provides π-π interaction toward the retention of the solutes. The results show that the functionalization of imidazole side groups is a feasible method for preparing new ionic liquid stationary phases.

8.
J Sep Sci ; 42(23): 3512-3520, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31556204

RESUMO

In this work, core-shell structured magnetic mesoporous carbon nanospheres were fabricated from the carbonization of metal-polyphenol coordination polymer-coated Fe3 O4 nanoparticles. The preparation method is simple, fast, versatile, and easy to scale up. Magnetic mesoporous carbon nanospheres exhibit a high specific surface area, high superparamagnetism, and high adsorption efficiencies for phthalates. Four phthalates were extracted from aqueous solutions by using magnetic mesoporous carbon nanospheres via magnetic solid phase extraction. Subsequent analysis was performed by using high-performance liquid chromatography with ultraviolet detection. The analytical method has good linearity in the concentration range of 1-200 ng/mL for diethyl phthalate, diisobutyl phthalate, and dicyclohexyl phthalate, and 3-200 ng/mL for dipropyl phthalate. The limits of detection were in the range of 0.10-0.62 ng/mL. Compared with previous methods, this method has a lower detection limit, wider linearity range, and faster adsorption and desorption rates. The results indicate that magnetic mesoporous carbon nanospheres are suitable for the enrichment of hydrophobic substances from aqueous solutions.

9.
J Chromatogr A ; 1607: 460401, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31376983

RESUMO

Boronate affinity is an important method for the enrichment and separation of cis-diol containing compounds, but most of the conventional boronate materials suffer from weak binding strength as well as low binding capacity towards glycoproteins due to the use of single boronic acids as ligands. In this work, a novel multidentate boronate magnetic adsorbent was assembled by using amined polyhedral oligomeric silsesquioxane as spacer and a diboronic acid as ligand. The specially designed adsorbent exhibited high adsorption capacity for cis-diols due to the high density of phenylbronic acid moieties. More interestingly, the dissociation constants toward glycoproteins on the material were lowered to be ∼10-6 M, being at least 3 orders lower than the single boronic acid bonded adsorbents. By comparing the binding properties of small molecules containing one and two pairs of cis-diols, the enhanced binding strength of glycoproteins on the multidentate boronate magnetic adsorbent was attributed to the synergistic binding of glycoproteins on the special interface. The new materials successfully captured glycoproteins from 1000-fold diluted egg white, suggesting that the material could be an optional alternative adsorbent for enriching trace glycoproteins from complex bio-samples.


Assuntos
Ácidos Borônicos/química , Glicoproteínas/química , Fenômenos Magnéticos , Compostos de Organossilício/química , Adenosina/análise , Adsorção , Animais , Galinhas , Cinamatos/análise , Depsídeos/análise , Cinética , Ligantes , Temperatura
10.
Food Chem ; 294: 104-111, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126442

RESUMO

Magnetic solid-phase extraction (MSPE), using a new reversed-phase/weak anion exchange mix-mode mesoporous magnetic SiO2 adsorbent, was assessed as an approach for reducing matrix effects in the analysis of six lipophilic marine biotoxins in shellfish using ultrahigh-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). The adsorbent showed greater adsorption capacity and selectivity for the analytes and, thus, the MSPE microspheres reduced the matrix effects significantly in the subsequent analysis. In the UPLC-MS/MS analysis, precursor and product ions of the analytes were monitored quantitatively and qualitatively using multiple reaction monitoring and product ion confirmation modes. The proposed method exhibited a linear correlation of 0.9980-0.9991 in the working range for azaspiracids (2.0-200.0 ng/mL) and okadaic acid and its derivatives dinophysistoxins (4.0-200.0 ng/mL) with satisfactory recoveries (82.8-118.6%, RSD < 12%), lower LODs (0.4-1.0 µg/kg) and LOQs (1.0-4.0 µg/kg) than existing methods. In addition, consumption of the adsorbent was reduced, and the MSPE operation is simple and rapid relative to alternatives. These results suggest the proposed method has potential for use in the analysis of lipophilic marine biotoxins in shellfish samples.


Assuntos
Cromatografia Líquida de Alta Pressão , Magnetismo , Toxinas Marinhas/análise , Microesferas , Ácido Okadáico/análise , Compostos de Espiro/análise , Espectrometria de Massas em Tandem , Óxido Ferroso-Férrico/química , Limite de Detecção , Toxinas Marinhas/isolamento & purificação , Ácido Okadáico/isolamento & purificação , Porosidade , Frutos do Mar/análise , Dióxido de Silício/química , Extração em Fase Sólida , Compostos de Espiro/isolamento & purificação
11.
J Sep Sci ; 42(10): 1896-1904, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30828963

RESUMO

Considering that the determination of pyrethroid residues is of value for the safety of food, a new poly(ionic liquid)-functionalized magnetic mesoporous nanoparticle was designed and used as an adsorbent in magnetic solid-phase extraction for the enrichment of eight pyrethroids. The porous structure and large surface area of the mesoporous silica shell endow the adsorbent with abundant binding sites. In contrast to the reported poly(ionic liquids) with only one kind of functional group in the cationic part, the new poly(ionic liquids) with mixed cyano and phenyl groups in cationic part matched the chemical structure of the analytes to improve extraction efficiency. Under the optimum conditions, an effective method was established for the determination of eight pyrethroids in apples. Adsorption equilibrium can be quickly reached in 1 min, greatly decreasing the extraction time. The linearity range was found to be 10-200 ng/g, and the detection limits ranged from 0.24 to 1.99 ng/g. Recoveries of analytes in apple samples ranged from 87.3 to 119.0%, with relative standard deviations varying in the range of 3-21.2% (intraday) and 0.3-15.2% (interday). The results indicate that the proposed method is a good candidate for pyrethroid residues in apple samples.


Assuntos
Contaminação de Alimentos/análise , Inseticidas/análise , Líquidos Iônicos/química , Nanopartículas de Magnetita/química , Malus , Piretrinas/análise , Adsorção , Sítios de Ligação , Cátions , Inocuidade dos Alimentos , Íons , Limite de Detecção , Magnetismo , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Microesferas , Reprodutibilidade dos Testes , Dióxido de Silício/química , Extração em Fase Sólida , Solventes , Água/análise
12.
Small ; 14(45): e1802290, 2018 11.
Artigo em Inglês | MEDLINE | ID: mdl-30307703

RESUMO

The rising dangers of bacterial infections have created an urgent need for the development of a new generation of antibacterial nanoagents and therapeutics. A new near-infrared 808 nm laser-mediated nitric oxide (NO)-releasing nanovehicle (MoS2 -BNN6) is reported through the simple assembly of α-cyclodextrin-modified MoS2 nanosheets with a heat-sensitive NO donor N,N'-di-sec-butyl-N,N'-dinitroso-1,4-phenylenediamine (BNN6) for the rapid and effective treatment of three typical Gram-negative and Gram-positive bacteria (ampicillin-resistant Escherichia coli, heat-resistant Escherichia faecalis, and pathogen Staphylococcus aureus). This MoS2 -BNN6 nanovehicle has good biocompatibility and can be captured by bacteria to increase opportunities of NO diffusion to the bacterial surface. Once stimulated by 808 nm laser irradiation, the MoS2 -BNN6 nanovehicle not only exhibits photothermal therapy (PTT) efficacy but also can precisely control NO release, generating oxidative/nitrosative stress. The temperature-enhanced catalytic function of MoS2 induced by 808 nm laser irradiation simultaneously accelerates the oxidation of glutathione. This acceleration disrupts the balance of antioxidants, ultimately resulting in significant DNA damage to the bacteria. Within 10 min, the MoS2 -BNN6 with enhanced PTT/NO synergetic antibacterial function achieves >97.2% inactivation of bacteria. The safe synergetic therapy strategy can also effectively repair wounds through the formation of collagen fibers and elimination of inflammation during tissue reconstruction.


Assuntos
Antibacterianos/química , Dissulfetos/química , Molibdênio/química , Óxido Nítrico/química , Antibacterianos/farmacologia , Dano ao DNA/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Luz , Testes de Sensibilidade Microbiana , Doadores de Óxido Nítrico/química , Staphylococcus aureus/efeitos dos fármacos
13.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1097-1098: 18-26, 2018 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-30196240

RESUMO

The modification with high-density functional groups is a widely used method to enhance the binding capacity of membrane adsorbers, where the types of the attached groups are crucial to achieve good selectivity for protein separation. In this work, a novel tetrazole-functionalized weak cation-exchange membrane with high-capacity was prepared by constructing tetrazole-containing polymer brushes on the surface of regenerated cellulose membrane via the combination of surface-initiated atom transfer radical polymerization (SI-ATRP) and "click chemistry" between cyano and azide. Densities of tetrazolyl groups on the membranes can be easily controlled by manipulating the polymerization time. The binding capacity of lysozyme increased with the polymerization time but eventually reached maximum due to the reduction of the utilization percentage of ion-exchange sites. The adsorption of newly designed membrane conforms to the feature of weak cation exchanger in terms of pH and salt effects, whereas the effect of pH exhibits a large difference from that on the carboxylic-functionalized ion-exchange membranes. Most importantly, the membranes possess higher dynamic binding capacity independent of the flow rate of mobile phase compared with the previously reported cation-exchange membranes. Featured with the unique properties, the modified membrane could simultaneously purify lysozyme and ovotransferrin from hen egg white at higher productivity. The present work provides a new alternative for membrane chromatography of biomacromolecules.


Assuntos
Cromatografia por Troca Iônica/métodos , Proteínas Recombinantes/isolamento & purificação , Tetrazóis/química , Concentração de Íons de Hidrogênio , Modelos Químicos , Muramidase , Polimerização , Proteínas Recombinantes/análise , Proteínas Recombinantes/química
14.
Mikrochim Acta ; 185(8): 361, 2018 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-29978437

RESUMO

The authors report on the preparation of composites made from graphene oxide (GO) and zeolitic imidazolate framework-8 (ZIF-GO), with various fractions of GO. GO acts as the template and as a modulator for the surface properties of the composites. It also improves the selective adsorption of specific proteins, i.e. hemoglobin (Hb) in this case. The adsorption capacity for Hb is as high as 436 mg g-1 when using a composite containing 20% of GO as sorbent, and 95% of specific activity is maintained for the Hb recovered. The sorbent is applied to selectively isolate Hb from human whole blood. Graphical abstract Graphene oxide-zeolitic imidazolate framework-8 composites (ZIF-GO) with varying mass ratios of GO were prepared in order to tune surface properties and to improve the adsorption selectivity toward hemoglobin.


Assuntos
Fracionamento Químico/métodos , Grafite/química , Hemoglobinas/isolamento & purificação , Imidazóis/química , Óxidos/química , Zeolitas/química , Adsorção , Hemoglobinas/análise , Humanos , Modelos Moleculares , Conformação Molecular
15.
Mikrochim Acta ; 185(8): 370, 2018 07 09.
Artigo em Inglês | MEDLINE | ID: mdl-29987393

RESUMO

Poly(2-naphthyl acrylate) was first grafted onto silica-coated magnetic nanoparticles by surface-initiated atom transfer radical polymerization to prepare a reversed-phase magnetic adsorbent. The resulting polymer brush displays enhanced extraction efficiency by offering active sites on the surfaces of adsorbent. It was applied to the preconcentration of the non-steroidal antiinflammatory drugs (NSAIDs) indomethacin (InDo) and diclofenac (DIC). These drugs interact with the sorbent through hydrophobic and π-interactions, and via electrostatic attraction. By coupling the magnetic solid-phase extraction with HPLC, a method for analysis of InDo and DIC in the environmental water samples was established. The limits of detection range from 0.62 to 0.64 ng·mL-1, and the relative standard deviations for intra-and inter-day analyses of spiked water samples are <11.9%, and relative recoveries are between 62.1 and 96.7%. Graphical abstract A reversed-phase magnetic adsorbent was prepared by grafting poly(2-naphthyl acrylate) brush on the surface of silica coated magnetic nanoparticles. Due to the two conjugated aromatic rings of the monomer, the polymer brush can effectively extract non-steroidal anti-inflammatory drugs through strong π- and hydrophobic interactions.


Assuntos
Métodos Analíticos de Preparação de Amostras/métodos , Anti-Inflamatórios não Esteroides/análise , Diclofenaco/análise , Indometacina/análise , Nanopartículas de Magnetita/química , Naftalenos/química , Polímeros/química , Adsorção , Anti-Inflamatórios não Esteroides/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Diclofenaco/isolamento & purificação , Indometacina/isolamento & purificação , Dióxido de Silício/química , Extração em Fase Sólida
16.
J Chromatogr A ; 1564: 16-24, 2018 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-29895408

RESUMO

A molecular bottlebrush functionalized magnetic adsorbent (magGO@bottlebrush) was fabricated in this work. Poly(hydroxyethyl methacrylate) (PHEMA) was first grafted from polydopamine coated magnetic graphene oxide via surface-initiated atom transfer radical polymerization (SI-ATRP) to produce the backbone of the molecular bottlebrush. Further modification was followed by grafting poly(styrene) via a second SI-ATRP from the PHEMA chains to yield the magGO@bottlebrush. Multiple interactions including hydrophobic, π-π stacking and π-π electron-donor-acceptor interactions greatly contributed to the solute retention. The adsorbent possessed unique shape selectivity, it provided high affinity to non-planar and non-linear compounds. Profiting from densely grafted phenyl and carbonyl groups on the adsorbent, multivalent interactions were exploited to enhance the selectivity for analytes with multiple recognition motifs. Bisphenol A (BPA) was chosen as a model analyte to test real applications of the adsorbent, considering its structural features. The adsorbent owns high adsorption capacity to BPA, and can be readily used for rapid and efficient enrichment of trace BPA from water samples.


Assuntos
Técnicas de Química Analítica/métodos , Monitoramento Ambiental/métodos , Magnetismo , Adsorção , Compostos Benzidrílicos/isolamento & purificação , Grafite/química , Indóis/química , Óxidos/química , Fenóis/isolamento & purificação , Poli-Hidroxietil Metacrilato/química , Polimerização , Polímeros/química , Água/química , Poluentes Químicos da Água/isolamento & purificação
17.
Mikrochim Acta ; 185(2): 113, 2018 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-29594664

RESUMO

The authors describe the preparation of copper-doped magnetic microspheres (Cu-Fe3O4) by a solvothermal method. Due to their good magnetic property and high affinity for compounds containing an imidazole moiety (containing N-H), they are excellent adsorbents for such compounds as tested by eighteen compounds. Specifically, a method has been developed for magnetic solid-phase extraction (MSPE) of theophylline (TP) from plasma. The method enables selective enrichment of TP over many potential interferents that can occur in plasma. Following elution with alkaline methanol, TP was quantified by HPLC-UV at a detection wavelength of 272 nm. Under the optimized conditions, a linear response is found for the 0.02 to 20 µg·mL-1 concentration range, and the limit of detection is as low as 3 ng·mL-1. Recoveries from spiked samples range from 91.2 to 100.4%, and the repeatabilities are between 2.9 and 12% (for n = 6). The method was successfully applied to the determination of TP in rabbit and rat plasma. Graphical abstract Copper-doped magnetic microspheres are described that show good magnetic property and high affinity for compounds containing an imidazole moiety (containing an N-H group). They were successfully applied to the selective extraction of theophylline in plasma.

18.
Mikrochim Acta ; 185(3): 189, 2018 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-29594797

RESUMO

Poly(3-acrylamidophenylboronic acid) (PAAPBA) was grafted onto polydopamine-coated magnetic graphene oxide via surface-initiated atom transfer radical polymerization to obtain a new kind of boronate affinity material (BAM). The BAM possesses good water dispersity and adsorption capacities as high as 154, 357, 588 and 1111 µmol·g-1 for adenosine, salbutamol, dopamine and catechol, respectively. For the molecules without nitrogen atoms, the BAM can selectively capture the cis-diols under the interference of non-cis-diols. For molecules containing nitrogen, the non-cis-diols are also retained, but much less than the cis-diols. The selectivity can be improved by adding salts to facilitate complexation and to suppress the electrostatic interaction between cis-diols and the boronic acid ligand. The BAM was successfully employed to the enrichment of catecholamines from real urine samples. Results indicate that it is a promising material for the pretreatment of real samples. Graphical abstract Schematic of the preparation of an ultrahigh capacity boronate affinity material by grafting polymer brush from polydopamine coated magnetic graphene oxide. The material has good selectivity to cis-diol-containing molecules and can be applied to enrich catecholamines in urine samples.

19.
Anal Bioanal Chem ; 410(6): 1709-1724, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29285646

RESUMO

In this study, the strategy of unique adsorbent combined with isotope labeled internal standards was used to significantly reduce the matrix effect for the enrichment and analysis of nine fluoroquinolones in a complex sample by liquid chromatography coupled to quadrupole linear ion trap mass spectrometry (LC-QqQLIT-MS/MS). The adsorbent was prepared conveniently by functionalizing Fe3O4@SiO2 microspheres with phenyl and tetrazolyl groups, which could adsorb fluoroquinolones selectively via hydrophobic, electrostatic, and π-π interactions. The established magnetic solid-phase extraction (MSPE) method as well as using stable isotope labeled internal standards in the next MS/MS detection was able to reduce the matrix effect significantly. In the process of LC-QqQLIT-MS/MS analysis, the precursor and product ions of the analytes were monitored quantitatively and qualitatively on a QTrap system equipped simultaneously with the multiple reaction monitoring (MRM) and enhanced product ion (EPI) scan. Subsequently, the enrichment method combined with LC-QqQLIT-MS/MS demonstrated good analytical features in terms of linearity (7.5-100.0 ng mL-1, r > 0.9960), satisfactory recoveries (88.6%-118.3%) with RSDs < 12.0%, LODs = 0.5 µg kg-1 and LOQs = 1.5 µg kg-1 for all tested analytes. Finally, the developed MSPE-LC-QqQLIT-MS/MS method had been successfully applied to real pork samples for food-safety risk monitoring in Ningxia Province, China. Graphical abstract Mechanism of reducing matrix effect through the as-prepared adsorbent.


Assuntos
Antibacterianos/análise , Fluoroquinolonas/análise , Análise de Alimentos/métodos , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Adsorção , Limite de Detecção , Imãs/química , Carne Vermelha/análise
20.
J Sep Sci ; 40(24): 4700-4708, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29044953

RESUMO

A novel approach that involved the grafting of diblock copolymer with two types of monomer onto substrate by sequential surface initiated-atom transfer radical polymerization was proposed to prepare a mixed-mode chromatographic stationary phase. The distinguishing feature of this method is that it can be applied in the preparation of various mixed-mode stationary phases. In this study, a new reverse-phase/ion-exchange stationary phase was prepared by grafting hydrophobic styrene and cationic sodium 4-styrenesulfonate by the proposed approach onto silica surface. The chromatographic properties of the prepared stationary phase were evaluated by the separation of benzene derivatives, anilines, and ß-agonists, and by the effect of pH values and acetonitrile content on the retention. Compared with typical RP columns, the prepared stationary phase achieved the better resolution and higher selectivity at a shorter separation time and lower organic content. Moreover, the application of the prepared column was proved by separating widely distributed polar and charged compounds simultaneously.

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