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1.
Food Chem ; 426: 136629, 2023 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-37331146

RESUMO

In this study, the contamination of 51 mycotoxins in 416 edible oils were determined by UPLC-MS/MS. Totally, twenty-four mycotoxins were detected and nearly half of the samples (46.9%, n = 195) were contaminated simultaneously with six to nine kinds of mycotoxins. The predominant mycotoxins and contamination characteristics varied depending on the type of oils. More specifically, four enniatins, alternariol monomethyl ether (AME) and zearalenone were the most frequent combination. Overall, peanut and sesame oils (10.7-11.7 mycotoxins on average) were found to be the most contaminated matrices whereas camellia and sunflower seed oils (1.8-2.7 species) were the opposite. Dietary exposure risks of mycotoxins were acceptable in most cases, however, the ingestion of aflatoxins (especially aflatoxin B1) through peanut and sesame oil (margin of exposure: 239.4-386.3 < 10000) exceeded the acceptable carcinogenic risk level. Meanwhile, the risks of cumulative ingestion through the food chain should be of great concern, especially sterigmatocystin, ochratoxin A, AME and zearalenone.


Assuntos
Micotoxinas , Zearalenona , Micotoxinas/análise , Zearalenona/análise , Cromatografia Líquida , Espectrometria de Massas em Tandem , Contaminação de Alimentos/análise , Óleos
2.
Environ Pollut ; 312: 120092, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36064063

RESUMO

To date, knowledge of internal human exposure to BPA and its analogues (particularly bisphenol S and bisphenol F, etc.) remains limited. In the present study, a method involving dispersive solid-phase extraction and LC/MS was proposed to investigate the contamination levels of 28 precursor bisphenols and 9 major metabolites in serum. The critical variables of preparation method were screened out by Plackett-Burman design and further optimized by central composite design. Left in optimal conditions, a total of 286 samples consisting of 153 males and 133 females were analyzed. The results showed that BPA dominated over all the cases with the highest positive rate (82.2% of all the surveyed people), and totally four metabolites (BPA ß-D-glucuronide, BPA monosulfate, BPA bis-(ß-D-glucuronide) and BPS monosulfate) were detectable. The occurrence of BPA bis-(ß-D-glucuronide) in serum is reported for the first time and its higher positive rate and contamination concentrations suggested that it may be a more important metabolite of BPA than others. Negligible potential risk of health effects to blood donors was observed, since the estimated exposure levels (mean 32.1 ng/kg bw/day, 95th 123.2 ng/kg bw/day) were well below far less than the temporary tolerable reference dose of BPA that recommended by the European Food Safety Authority (4 µg/kg bw/day by). The reference level of BPA for healthy population was determined to be 4.09 µg/L via the percentile method.


Assuntos
Glucuronídeos , Espectrometria de Massas em Tandem , Compostos Benzidrílicos/análise , Cromatografia Líquida , Feminino , Humanos , Masculino , Fenóis , Extração em Fase Sólida
3.
J Chromatogr A ; 1659: 462486, 2021 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-34710806

RESUMO

A rapid and efficient QuEChERS-based preparation method was established for the simultaneous determination of 43 mycotoxins in chestnut and jujube (Chinese date). The contaminants were extracted using acetonitrile and subjected to dispersive solid-phase extraction for further clean-up. Central composite design was conducted to overcome the limitations of conventional optimization methods, and assess the interaction effects between variables and reach the true optimal conditions. Quantitative analysis was performed on UHPLC-MS/MS with the aid of stable isotope internal standards and matrix-matched curves, whereas qualitative identification was carried out by using high-resolution MS based on exact masses and fragmentation patterns. In addition to the mycotoxins that are routinely monitored (like aflatoxins, ochratoxin A, etc.), this study also revealed a non-negligible contamination of zearalenone (56/170), beauvericin (52/170), enniatin B (43/170), and alternariol monomethyl ether (42/170) in chestnut and jujube, especially the chestnut flour.


Assuntos
Micotoxinas , Ziziphus , Frutas/química , Micotoxinas/análise , Extração em Fase Sólida , Espectrometria de Massas em Tandem
4.
Food Chem ; 294: 160-170, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31126448

RESUMO

An effective method has been developed for the simultaneous determination of four bisphenols (bisphenol A, S, F and B) in various foodstuffs. The contaminants were extracted by QuEChERS-based strategy and subjected to ion-exchange solid-phase extraction for further clean-up. The critical variables were screened by Plackett-Burman design and then optimized by central composite design. Under the optimized conditions, satisfactory accuracy (recoveries 76%-116%) and precision (RSDs < 12%) were achieved. The established method was then used to assess the contamination status of 379 real samples. Bisphenol A was demonstrated to be the predominant bisphenol with highest incidence (79.7%) and average concentration (14.3 µg/kg). The positive rates (mean concentration) of bisphenol S, F and B were 37.7% (1.6 µg/kg), 26.9% (1.4 µg/kg) and 0.0% (not detected), respectively. Finally, the daily dietary intakes of ∑4bisphenolsfor adult residents were estimated (55.9-76.1 ng/kg bw/day) according to the contamination concentrations and the daily recommended intakes.


Assuntos
Compostos Benzidrílicos/análise , Análise de Alimentos/métodos , Fenóis/análise , Sulfonas/análise , Compostos Benzidrílicos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Exposição Dietética , Humanos , Limite de Detecção , Fenóis/isolamento & purificação , Extração em Fase Sólida , Sulfonas/isolamento & purificação , Espectrometria de Massas em Tandem
5.
RSC Adv ; 9(30): 17415-17416, 2019 May 29.
Artigo em Inglês | MEDLINE | ID: mdl-35532402

RESUMO

[This corrects the article DOI: 10.1039/C4RA14150D.].

6.
Anal Chim Acta ; 1046: 208, 2019 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-30482301

RESUMO

This article has been retracted at the request of the Editor after the corresponding author pointed the Editor to comments from an anonymous reader. The article reports electron micrographs of different preparations while showing identical images as used in previous publications by the same authors. The particles in Fig. 4C (SEM image of Fe3O4@SiO2) are identical to each other and the corresponding author confirmed that these have been copy-pasted. In addition, these particles have previously been communicated as different substances in Fig. 1B from Pan et al., J. Mater. Chem. A, 2015,3, 23042-23052 (DOI: 10.1039/C5TA05840F) and Fig. 3F from Pan et al., Anal. Methods, 2017,9, 5281-5292 (DOI: 10.1039/C7AY01444A). Furthermore, the curves in Fig. 7, especially the baseline, shows a remarkable similarity to Fig. 8 from Pan et al., J. Mater. Chem. A, 2015,3, 23042-23052 (DOI: 10.1039/C5TA05840F) and Fig. 5F from Pan et al., J. Mater. Chem. A, 2014,2, 15345-15356 (DOI: 10.1039/c4ta02600d). The manipulation of images and data in this way is a serious offense to the integrity of the scientific community and casts doubts on all the data, and accordingly also the conclusions based on that data, in this publication. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process. This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal).

7.
Talanta ; 185: 411-418, 2018 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-29759220

RESUMO

The novel quaternary ammonium modified magnetic carboxyl-carbon nanotubes (QA-Mag-CCNTs) have been synthesised and characterized. QA-Mag-CCNTs were applied in magnetic dispersive solid phase extraction (Mag-dSPE) for preconcentration of perchlorate from tea leaves prior to liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS) analysis. The Mag-dSPE procedure for preconcentration of perchlorate succeed in overcoming the flaw (containing target analyte randomly) of commercially available SPE cartridge. Under optimal conditions, the results showed higher extraction efficiency of QA-Mag-CCNTs, with recoveries between 85.2% and 107%. And the satisfactory precision with inter-day and intra-day RSD values were lower than 8.0%. Furthermore, QA-Mag-CCNTs were evaluated for reuse up to 20 times. The limit of quantification (LOQ) for perchlorate was 8.21 ng kg-1. The developed method was successfully applied in tea leaves for food-safety risk monitoring in Zhejiang province, China. The results showed the concentrations of perchlorate in 229 out of 240 collected samples were in the range of 0.082-988 µg kg-1. It was confirmed that QA-Mag-CCNTs were highly effective materials used for preconcentration of perchlorate.


Assuntos
Nanotubos de Carbono/química , Percloratos/análise , Compostos de Amônio Quaternário/química , Chá/química , Cromatografia Líquida , Campos Magnéticos , Estrutura Molecular , Folhas de Planta/química , Espectrometria de Massas em Tandem
8.
J Chromatogr A ; 1553: 16-24, 2018 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-29691057

RESUMO

A novel hydrophilicity nano-titania coating modified magnetic graphene oxide (HTC-Mag-GO) has been synthesized. It has been evaluated in PRiME (process, robustness, improvements, matrix effects, ease of use) pass-through cleanup procedure for human blood prior to analysis of fipronil and its metabolites, i.e., fipronil sulphone, fipronil sulphide and fipronil desulfinyl by liquid chromatography-tandem quadrupole mass spectrometry (LC-MS/MS). Compared with the Oasis PRiME HLB cartridge, HTC-Mag-GO is much more effective for the removal of matrix effect. Furthermore, it is beneficial to protect the chromatographic column and ESI source by the HTC-Mag-GO PRiME pass-through cleanup procedure, resulting from the much cleaner blood samples. Under the optimum conditions, the results show higher cleanup efficiency of HTC-Mag-GO with recoveries in the range of 92.4%-108%. Especially, the HTC-Mag-GO is also evaluated for reuse (20 times) without much sacrifice of the cleanup efficiency. The limits of quantification (LOQs) for fipronil, fipronil sulphone, fipronil sulphide and fipronil desulfinyl are 8.9 ng/L, 7.2 ng/L, 8.0 ng/L and 42 ng/L, respectively. The developed method has also been successfully applied to monitoring fipronil and its metabolites in 120 blood samples, and fipronil sulphone is detected in six samples with concentrations in the range of 12.1 ng/L-106 ng/L. Further, the well validation results and the application to analysis of fipronil and its metabolites in real samples demonstrate the applicability to toxico kinetic studies and clinical studies.


Assuntos
Cromatografia Líquida , Grafite/química , Pirazóis/sangue , Espectrometria de Massas em Tandem , Titânio/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Cinética , Fenômenos Magnéticos , Nanopartículas , Óxidos/química
9.
J Chromatogr B Analyt Technol Biomed Life Sci ; 1068-1069: 15-23, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-29028614

RESUMO

Two analytical approaches, including ultra-high performance liquid chromatograph linked with photo-diode array/fluorescence detector, and ultra-high performance liquid chromatography-tandem mass spectrometry, have been proposed for simultaneous determination of five Alternaria toxins in cereals, which both based on QuEChERS strategy. After QuEChERS extraction and salting out, the collected supernatant was subjected to an extra dispersive liquid-liquid microextraction step prior to quantitative analysis. Response surface methodology based on central composite design was employed to optimize the micro-extraction conditions. During photo-diode array/fluorescence detector method validation, satisfactory analytical characteristics, in terms of selectivity, recovery (72.7%-109.1%), precision (inter-day RSDs <9.6%), sensitivity (limits of quantification ranged from 2.1µgkg-1 to 120.0µgkg-1) and linearity (R2 all higher than 0.9984), were achieved. Mass spectrometry method was employed as a certified method for accuracy. The two methodologies were successfully applied to 71 samples including three different matrices and the quantitative results were compared. As the result of non-parametric test shown, the established two analytical approach exhibited comparable quantitative accuracy to each other.


Assuntos
Alternaria , Cromatografia Líquida de Alta Pressão/métodos , Microextração em Fase Líquida/métodos , Micotoxinas/análise , Limite de Detecção , Modelos Lineares , Micotoxinas/química , Micotoxinas/isolamento & purificação , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
10.
Sci Total Environ ; 580: 966-973, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27989475

RESUMO

Bimetallic oxide CuFeO2 as a new heterogeneous catalyst has shown much higher catalytic ability for activating peroxide than single-metal oxides. The present work demonstrated a synergistic microwave (MW) enhanced Fenton-like process with CuFeO2 for rapid decolorization of azo dye Orange G (OG). The MW irradiation dramatically enhanced the OG degradation efficiency, achieving 99.9% decolorization within 15min at pH5. The XRD analysis of reused CuFeO2, together with metal leaching tests, indicated merits of recycling for CuFeO2. The subsequent surface element analysis by XPS for fresh and used CuFeO2 showed a complex network for reactions between copper-iron redox pairs and surface hydroxyl groups, leading to a synergistic Fenton-like system accelerated by MW irradiation. In the CuFeO2 initiated Fenton-like reactions, several oxidant species (i.e., OH, O2-, electron hole, and FeIVO) responsible to the OG oxidation were identified by quenching experiments, showing the MW generated high temperature and "hot spots" enhanced the yield of OH by generation of electron-hole pairs. Further, the 26 detected degradation products confirmed the OH dominant oxidation of OG. This study shows that the MW-enhanced Fenton-like reaction using CuFeO2 has potential applications for rapid decolorization of dye effluent.

11.
J Chromatogr A ; 1459: 38-46, 2016 Aug 12.
Artigo em Inglês | MEDLINE | ID: mdl-27425762

RESUMO

A planar graphene oxide-based magnetic ionic liquid nanomaterial (PGO-MILN) was synthesized. The prepared PGO-MILN was characterized by transmission electronmicroscopy (TEM) and Fourier-transform infrared spectrometry (FTIR). The results of adsorption experiments showed that the PGO-MILN had great adsorption capacity for 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Based on the adsorption experimental data, a sensitive magnetic method for determination of the five CPs in environmental water samples was developed by an effective magnetic solid-phase extraction (MSPE) procedure coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The effects of main MSPE parameters including the solution pH, extraction time, desorption time, and volume of desorption solution on the extraction efficiencies had been investigated in detail. The recoveries ranged from 85.3 to 99.3% with correlation coefficients (r) higher than 0.9994 and the linear ranges were between 10 and 500ngL(-1). The limits of detection (LODs) and limits of quantification (LOQs) of the five CPs ranged from 0.2 to 2.6ngL(-1) and 0.6 to 8.7ngL(-1), respectively. The intra- and inter- day relative standard deviations (RSDs) were in the range from 0.6% to 7.4% and from 0.7% to 8.4%, respectively. It was confirmed that the PGO-MILN was a kind of highly effective MSPE materials used for enrichment of trace CPs in the environmental water.


Assuntos
Clorofenóis/análise , Cromatografia Líquida de Alta Pressão , Grafite/química , Líquidos Iônicos/química , Nanoestruturas/química , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/análise , Adsorção , Óxido Ferroso-Férrico/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Magnetismo , Microscopia Eletrônica de Transmissão , Óxidos/química , Dióxido de Silício/química , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/isolamento & purificação
12.
Anal Chim Acta ; 919: 34-46, 2016 May 05.
Artigo em Inglês | MEDLINE | ID: mdl-27086097

RESUMO

In this study, graphene oxide-encapsulated core-shell magnetic microspheres (GOE-CS-MM) were fabricated by a self-assemble approach between positive charged poly(diallyldimethylammonium) chloride (PDDA)-modified Fe3O4@SiO2 and negative charged GO sheets via electrostatic interaction. The as-prepared GOE-CS-MM was carefully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), vibrating sample magnetometer analysis (VSM), and X-ray photoelectron spectroscopy (XPS), and was used as a cleanup adsorbent in magnetic solid-phase extraction (MSPE) for determination of 15 trace-level environmental phenols in seafood coupled to liquid chromatography-tandem mass spectrometry (LC-MS/MS). The obtained results showed that the GOE-CS-MM exhibited excellent cleanup efficiency and could availably reduce the matrix effect. The cleanup mechanisms were investigated and referred to π-π stacking interaction and hydrogen bond between GOE-CS-MM and impurities in the extracts. Moreover, the extraction and cleanup conditions of GOE-CS-MM toward phenols were optimized in detail. Under the optimized conditions, the limits of detection (LODs) were found to be 0.003-0.06 µg kg(-1), and satisfactory recovery values of 84.8-103.1% were obtained for the tested seafood samples. It was confirmed that the developed method is simple, fast, sensitive, and accurate for the determination of 15 trace environmental phenols in seafood samples.


Assuntos
Poluentes Ambientais/análise , Grafite/química , Imãs , Microesferas , Óxidos/química , Fenóis/análise , Alimentos Marinhos/análise , Cromatografia Líquida , Espectrometria de Massas em Tandem
13.
J Sep Sci ; 39(12): 2396-405, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27121535

RESUMO

A new facile, rapid, inexpensive, and sensitive method for the analysis of six trace trichlorophenols in seawater samples was developed by magnetic micro-solid-phase extraction coupled to liquid chromatography with tandem mass spectrometry. Core-shell covalently functionalized ferroferric oxide coated with aminated silicon dioxide and decorated with multiwalled carbon nanotubes was applied as an adsorbent to perform the extraction process. The effect of factors including solution pH, contact time, adsorbent amount, and ionic strength were investigated in detail. The obtained results revealed that the proposed adsorbent was a highly effective and low-cost magnetic micro-solid-phase extraction material for the enrichment of 2,3,4-trichlorophenol, 2,3,5-trichlorophenol, 2,3,6-trichlorophenol, 2,4,5-trichlorophenol, 2,4,6-trichlorophenol, and 3,4,5-trichlorophenol from seawater. Under the optimized conditions, the recoveries ranged from 88.0 to 99.5% at the three spiking levels, the limits of detection and the limits of quantification were 0.002 and 0.007 µg/L for the six trichlorophenols, respectively. The intra- and interday relative standard deviations were 2.0-6.7 and 4.5-8.9%, respectively. The calibration curves showed a good linearity in the range of 0.02-5.0 µg/L. The routine run analyses showed that the developed method was fast, simple, accurate, solvent-saving and high resolution, and it was suitable for the determination of trace trichlorophenols in seawater.

14.
J Chromatogr A ; 1431: 36-46, 2016 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-26777090

RESUMO

We report the template-free fabrication of three-dimensional hierarchical nanostructures, i.e., three-dimensional interconnected magnetic chemically modified graphene oxide (3D-Mag-CMGO), through a simple and low-cost self-assembly process using one-pot reaction based on solvothermal method. The excellent properties of the 3D-Mag-CMGO are characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), vibrating sample magnetometer (VSM), FTIR, elementary analyzer (EA) and X-ray photoelectron spectroscopy (XPS). The easiness-to-handle of the magnetic dispersive solid phase extraction (Mag-dSPE) procedure is developed for preconcentration of 21 allergenic disperse dyes from river water. The obtained results show the higher extraction capacity of 3D-Mag-CMGO with recoveries between 80.0-112.0%. Furthermore, an ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) method for determination of 21 allergenic disperse dyes in river at sub-ppt levels has been developed with pretreatment of the samples by Mag-dSPE. The limits of quantification (LOQs) for the allergenic disperse dyes are between 0.57-34.05ng/L. Validation results on linearity, specificity, trueness and precision, as well as on application to the analysis of 21 allergenic disperse dyes in fifty real samples demonstrate the applicability to environment monitoring analysis.


Assuntos
Alérgenos/análise , Cromatografia Líquida , Corantes/análise , Monitoramento Ambiental/métodos , Óxidos/química , Rios/química , Espectrometria de Massas em Tandem , Grafite/química , Magnetismo
15.
J Sep Sci ; 39(4): 762-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26632107

RESUMO

A novel triethylenetetramine-functionalized magnetic graphene oxide composite was prepared and used as a magnetic solid-phase extraction adsorbent for the fast detection of ten trace-level phenolic environmental estrogens in environmental water. The synthesized material was carefully characterized by scanning electron microscopy, transmission electron microscopy, vibrating sample magnetometry, and X-ray photoelectron spectroscopy to confirm the structure and components. The adsorption and desorption conditions of the adsorbent toward phenolic environmental estrogens were optimized in detailed to obtain the best extraction recovery and elution efficiency. Under the optimum conditions, the limits of detection of the method for ten phenolic environmental estrogens were in range of 0.15-1.5 ng/L, which was lower than the reported methods for phenolic environmental estrogens detection in literatures. This could be contributed to the unique structure and property of the as-prepared material. The developed method was successfully applied for the determination of environmental water samples with recoveries ranging from 88.5 to 105.6%.


Assuntos
Estrogênios/química , Grafite/química , Magnetismo , Óxidos/química , Fenol/química , Trientina/química , Água/química , Adsorção , Cromatografia Líquida de Alta Pressão , Monitoramento Ambiental/métodos , Poluentes Ambientais , Limite de Detecção , Impressão Molecular , Polímeros/química , Reprodutibilidade dos Testes , Solventes/química , Poluentes Químicos da Água/química
16.
Environ Sci Pollut Res Int ; 23(2): 1529-39, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26377965

RESUMO

The easiness-to-handle of the magnetic dispersive solid phase extraction (Mag-dSPE) procedure was developed for preconcentration of 24 steroid hormones in river water. Ethylenediamine-functionalized magnetic carbon nanotubes (EDA@Mag-CNTs) were synthesised by a simple one-pot reaction and were used as sorbent in Mag-dSPE procedure. The properties of the EDA@Mag-CNTs were characterized by transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). An ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) method for determination of 24 steroid hormones in river water at nanograms per liter had been developed with pretreatment of the samples by Mag-dSPE. The obtained results demonstrated the higher extraction capacity of EDA@Mag-CNT Mag-dSPE with recoveries between 82.1 and 113%. The limits of quantification (LOQs) for the steroid hormone were between 0.020 and 1.00 ng/L. The developed method had been successfully applied to 60 river water samples, and it was confirmed that EDA@Mag-CNT Mag-dSPE was a highly effective extraction method for the steroid hormone analyses.


Assuntos
Hormônios Esteroides Gonadais/análise , Rios/química , Extração em Fase Sólida/métodos , Esteroides/análise , Espectrometria de Massas em Tandem/métodos , Cromatografia Líquida/métodos , Etilenodiaminas , Nanotubos de Carbono/química
17.
J Chromatogr A ; 1422: 1-12, 2015 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-26477521

RESUMO

Microcystins (MCs), a group of cyclic heptapeptide heaptoxins and tumor promoters, are generated by cyanobacteria occurring in surface waters, such as eutrophic lakes, rivers, and reservoirs. In this present study, a novel double-sided magnetic molecularly imprinted polymer modified graphene oxide (DS-MMIP@GO) based magnetic solid-phase extraction (MSPE) method was developed for fast, effective and selective enrichment, and recognition of trace MCs in environmental water samples combined with high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). The synthesized novel DS-MMIP@GO was used as the adsorbents in this work and was carefully characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and Raman spectra. The adsorption and desorption conditions of DS-MMIP@GO toward MCs were optimized in detail to obtain the highest binding capacity, selectivity, and release efficiency. Under the optimum conditions, the enrichment factors of the method for eight target MCs were found to be 2000. The limits of quantitation (LOQs) of the method for eight MCs were in range of 0.1-2.0ngL(-1). The double-sided MMIP modified structure provided DS-MMIP@GO with abundant adsorption sites and permitted it to exhibit excellent enrichment and selectivity toward trace-level MCs. The proposed method was successfully applied for the analysis of environmental water samples with recoveries ranging from 84.1 to 98.2%. Compared to conventional methods for MCs detection reported in literatures, the one developed in this work based on DS-MMIP@GO and LC-MS/MS showed much faster, more sensitive, and more convenient.


Assuntos
Cromatografia Líquida , Monitoramento Ambiental/métodos , Água Doce/química , Microcistinas/análise , Microcistinas/isolamento & purificação , Óxidos/química , Espectrometria de Massas em Tandem , Grafite/química , Magnetismo , Microscopia Eletrônica de Transmissão , Polímeros/química , Extração em Fase Sólida , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
18.
Ultrason Sonochem ; 22: 167-73, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25132495

RESUMO

In this work, the decolorization of azo dye Orange G (OG) in aqueous solution by aluminum powder enhanced by ultrasonic irradiation (AlP-UI) was investigated. The effects of various operating operational parameters such as the initial pH, initial OG concentration, AlP dosage, ultrasound power and added hydrogen peroxide (H2O2) concentration were studied. The results showed that the decolorization rate was enhanced when the aqueous OG was irradiated simultaneously by ultrasound in the AlP-acid systems. The decolorization rate decreased with the increase of both initial pH values of 2.0-4.0 and OG initial concentrations of 10-80mg/L, increased with the ultrasound power enhancing from 500 to 900W. An optimum value was reached at 2.0g/L of the AlP dosage in the range of 0.5-2.5g/L. The decolorization rate enhanced significantly by the addition of hydrogen peroxide in the range of 10-100mM to AlP-UI system reached an optimum value of 0.1491min(-1). The decolorization of OG appears to involve primarily oxidative steps, the cleavage of NN bond, which were verificated by the intermediate products of OG under the optimal tested degradation system, aniline and 1-amino-2-naphthol-6,8-disulfonate detected by the LC-MS.

19.
J Chromatogr A ; 1362: 34-42, 2014 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-25160956

RESUMO

A novel planar-structure amine-functional magnetic polymer modified graphene oxide nanocomposite (NH2-MP@GO) was synthesized. The properties were characterized by transmission electron microscopy (TEM) and Fourier-transform infrared spectrometry (FTIR). The obtained adsorption results showed that the NH2-MP@GO had great adsorptive ability toward five chlorophenols (CPs), including 2-chlorophenol (2-CP), 2,4-dichlorophenol (2,4-DCP), 2,4,6-trichlorophenol (2,4,6-TCP), 2,3,4,6-tetrachlorophenol (2,3,4,6-TeCP) and pentachlorophenol (PCP). Based on these, an effective magnetic solid-phase extraction (MSPE) procedure coupled with high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the preconcentration and determination of the five CPs in environmental water samples was developed. Various experimental parameters that could affect the extraction efficiencies had been investigated in detail. Under the optimum conditions, the enrichment factors of the method for the target CPs were found to be 1000. The proposed method was successfully applied for the analysis of environmental water samples with recoveries ranging from 86.4 to 99.8% with correlation coefficients (R) higher than 0.9994. Good linearities were obtained ranging from 10 to 500ng/L for 2-CP, 5 to 500ng/L for 2,4-DCP, 2 to 500ng/L for 2,4,6-TeCP and 2,3,4,6-TeCP, and 1 to 500ng/L for PCP, respectively. The limits of quantitation for the five CPs were 0.6-9.2ng/L. It was confirmed that the planar-structure NH2-MP@GO was a kind of highly effective MSPE materials used for the trace CPs analyses.


Assuntos
Aminas/química , Clorofenóis/análise , Cromatografia Líquida/métodos , Óxidos/química , Extração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos , Água/química , Adsorção , Cromatografia Líquida/instrumentação , Grafite/química , Concentração de Íons de Hidrogênio , Limite de Detecção , Fenômenos Magnéticos , Polímeros/química , Extração em Fase Sólida/instrumentação , Espectrometria de Massas em Tandem/instrumentação
20.
J Chromatogr A ; 1346: 123-8, 2014 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-24797395

RESUMO

A novel, simple and sensitive method based on the use of magnetic dispersive solid-phase extraction (M-dSPE) procedure combined with ultra-fast liquid chromatography-tandem quadrupole mass spectrometry (UFLC-MS/MS) was developed to determine seven synthetic pigments (tartrazine, amaranth, carmine, sunset yellow, allura red, brilliant blue and erythrosine) in wines and soft drinks. An amino-functionalized low degrees of cross-linking magnetic polymer (NH2-LDC-MP) was synthesized via suspension polymerization, and characterized by transmission electron microscopy (TEM). The NH2-LDC-MP was used as the M-dSPE sorbent to remove the matrix from the solution, and the main factors affecting the extraction were investigated in detail. The obtained results demonstrated the higher extraction capacity of NH2-LDC-MP with recoveries between 84.0 and 116.2%. The limits of quantification (LOQs) for the seven synthetic pigments were between 1.51 and 5.0µg/L in wines and soft drinks. The developed M-dSPE UFLC-MS/MS method had been successfully applied to the real wines and soft drinks for food-safety risk monitoring in Zhejiang Province, China. The results showed that sunset yellow was in three out of thirty soft drink samples (2.95-42.6µg/L), and erythrosine in one out of fifteen dry red wine samples (3.22µg/L), respectively. It was confirmed that the NH2-LDC-MP was a kind of highly effective M-dSPE materials for the pigments analyses.


Assuntos
Bebidas Gaseificadas/análise , Cromatografia Líquida , Corantes/análise , Tecnologia de Alimentos/métodos , Extração em Fase Sólida , Espectrometria de Massas em Tandem , Vinho/análise , China , Fenômenos Magnéticos
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