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1.
J Chromatogr A ; 1626: 461360, 2020 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-32797839

RESUMO

Conjugated microporous polymers (CMPs) with uniform morphology have shown fascinating application in the separation science. In this study, metal-free Knoevenagel condensation was adopted to prepare spherical sp2 carbon-conjugated microporous polymers, which used tetrakis(4-formylphenyl)methane and 1,4-phenylenediacetonitrile as monomers. Due to the remarkable extraction capability for carbamate pesticides (CPs), the as-synthesized CMPs were fabricated as the coating for solid-phase microextraction (SPME). After optimized SPME parameters (adsorption time, salt concentration, sample pH, adsorption temperature, desorption time, desorption solvent and desorption volume), ten CPs in water samples were quantified by ultrahigh performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Linearity in the range 0.005-100 ng mL-1 with low detection limits of 0.00060-0.017 ng mL-1 was obtained. The intra-day and inter-day precisions expressed as relative standard deviations were 1.5-8.1% and 1.1-8.0%, respectively. Fiber-to-fiber reproducibility was below 7.3%. The CMPs-SPME-UPLC-MS/MS method was applied to detect trace CPs in real water samples with relative recoveries from 91.8% to 108%.


Assuntos
Carbamatos/análise , Microextração em Fase Sólida/métodos , Poluentes Químicos da Água/análise , Adsorção , Carbamatos/isolamento & purificação , Cromatografia Líquida de Alta Pressão , Praguicidas/análise , Praguicidas/isolamento & purificação , Polímeros/química , Porosidade , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem , Poluentes Químicos da Água/isolamento & purificação
2.
J Environ Sci Health B ; 55(8): 726-731, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32558617

RESUMO

It is crucial to develop practical procedures for the control and reduction of pesticide residues in oil productions from farm to dining table. In this study, the dissipation behaviors of typical fungicide from rapeseed to oil production were studied to reveal relationship among spraying stage, application dosage, household oil processing stage, and pesticide residues. In the field trials, rape plants were sprayed with carbendazim at three different dosages during flowering period. Transfer assessment of carbendazim residues from rapeseed to oil production during household oil processing via different press techniques was determined using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The recoveries of carbendazim in rapeseed samples, meals after squeezing samples, and rapeseed oil samples ranged from 82.5% to 93.6% with relative standard deviations (RSDs) <5.2%. The validation results illustrated that the methods were reliable and sensitive. The average processing factor (PF) during household oil processing via hot press technique and cold press technique was 0.15 and 0.51, respectively. This study demonstrated that household oil processing could significantly reduce the pesticide residues, especially by hot press technique.


Assuntos
Benzimidazóis/análise , Carbamatos/análise , Contaminação de Alimentos/análise , Manipulação de Alimentos/métodos , Resíduos de Praguicidas/análise , Óleo de Brassica napus/análise , Brassica napus/química , Cromatografia Líquida de Alta Pressão/métodos , Características da Família , Fungicidas Industriais/análise , Óleo de Brassica napus/química , Reprodutibilidade dos Testes , Espectrometria de Massas em Tandem/métodos
3.
Food Chem ; 327: 127075, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32446026

RESUMO

The needing of rapid and sensitive detection method for pesticides is increasing, to facilitate its detection without complicated instruments. Herein, a novel paper-based senor was developed for the visual detection of three carbamate pesticides (metolcarb, carbofuran, and carbaryl) based on CdTe quantum dots (QDs) and nano zinc 5, 10, 15, 20-tetra(4-pyridyl)-21H-23H-porphine (nano ZnTPyP) with a "turn-off-on" mode. This fluorescence sensing model could be applied in the highly selective and sensitive detection of carbamate pesticides both by fluorescence spectrometry or paper-based sensors. Based on the extracted RGB color values of paper, the partial least squares regression (PLSR) was used to accurately quantify the concentrations of carbamate pesticides in different food matrices (apple, cabbage and tea water). This method featured in high speed, low price and high accuracy, and provided a new strategy for the detection of food safety.


Assuntos
Compostos de Cádmio/química , Carbamatos/análise , Análise de Alimentos , Resíduos de Praguicidas/análise , Porfirinas/química , Pontos Quânticos , Telúrio/química , Fluorescência , Alimentos , Limite de Detecção , Nanoestruturas , Espectrometria de Fluorescência
4.
J Chromatogr A ; 1616: 460795, 2020 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-31918849

RESUMO

Based on our previous work with "pseudostationary-ion exchanger sweeping", we use this strategy to develop a sensitive, reliable and robust method for the analysis of the newly-FDA approved hepatitis C antiviral drugs namely; sofosbuvir (SOV), daclatasvir (DAC), ledipasvir (LED) and velpatasvir (VEP) in their pure forms and co-formulated pharmaceutical dosage forms using micellar electrokinetic chromatography (MEKC) as a separation method. For the first time, a successful separation of all the investigated compounds was achieved in less than 8 min using a basic background electrolyte (BGE) composed of 25 mmol L-1 SDS + 20% (v/v) ACN (acetonitrile) in 10 mmol L-1 disodium tetraborate buffer (final apparent pH is 9.90). A special focus was given to optimize the composition of the sample matrix to maintain the solubility of the analytes within the sample zone while gaining additional benefits regarding analyte zone focusing. It was found that replacing phosphoric acid (as a sample matrix) with a zwitterionic/isoelectric buffering compound (L-glutamic acid) has a substantial positive impact on the obtained enrichment efficiency. The interplay of other enrichment principles such as the retention factor gradient effect (RFGE) is also discussed. A full validation study is performed based on the pharmacopeial and ICH guidelines. The obtained limits of detection and quantitation are as low as 0.63 and 1.3 µg mL-1; respectively for SOV and DAC and 1.3 and 2.5 µg mL-1; respectively for LED and VEP using UV-DAD as a detection method. The selectivity of the developed method for determination of the studied compounds in their pharmaceutical dosage forms or in the presence of ribavirin (RIB) or elbasvir (ELB), which are other prescribed medications in the treatment regimen of patients with hepatitis C virus infection, is demonstrated. It is shown that with acidic sample matrix and basic BGE, an efficient and precise approach was designed in which analyte adsorption on the capillary wall was minimized while keeping repeatable peak height, peak area and migration time together with the highest possible enrichment efficiency.


Assuntos
Antivirais/análise , Cromatografia Capilar Eletrocinética Micelar/métodos , Hepacivirus/efeitos dos fármacos , Sofosbuvir/análise , Adsorção , Antivirais/química , Benzimidazóis , Benzofuranos , Carbamatos/análise , Carbamatos/química , Ciclodextrinas/química , Formas de Dosagem , Eletrólitos/química , Fluorenos , Compostos Heterocíclicos de 4 ou mais Anéis/análise , Compostos Heterocíclicos de 4 ou mais Anéis/química , Humanos , Imidazóis/análise , Imidazóis/química , Limite de Detecção , Modelos Lineares , Metanol/química , Reprodutibilidade dos Testes , Sofosbuvir/química , Solubilidade , Temperatura , Ureia/química
5.
Food Chem ; 309: 125756, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31776048

RESUMO

In this work, a selective sorbent for carbendazim was prepared by the thermal immobilization of the poly(glycidoxypropylmethyl-co-dimethylsiloxane), PGDMS, on silica. The lab-made Si(PGDMS) sorbent was physicochemically and morphologically characterized and was used into the pipette tip for the disposable pipette extraction (DPX) of carbendazim residues of orange juice. The DPX method was optimized from a central composite design and validated according to the SANTE/11813/2017 document recommended by the European Union. The proposed method presented recoveries between 93 and 110% with RSD <16% and the limit of quantification below the MRL for carbendazim in citrus. The whole sample preparation process was carried out at less than 3 min, with good accuracy and precision without the need of any cleanup step or electrical equipment, allowing its portability for the extraction of carbendazim residues in orange juice.


Assuntos
Benzimidazóis/análise , Carbamatos/análise , Cromatografia Líquida de Alta Pressão/métodos , Citrus/química , Sucos de Frutas e Vegetais/análise , Citrus/metabolismo , Limite de Detecção , Polímeros/química , Dióxido de Silício/química , Extração em Fase Sólida/instrumentação , Extração em Fase Sólida/métodos , Temperatura
6.
Sci Total Environ ; 695: 133790, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31422335

RESUMO

Neonicotinoid insecticides (NNIs) are a relatively new class of insecticides, and carbendazim (CBDZ) is a representative antifungal biocide. The occurrence of them in indoor dust was not documented in China. In this study, 336 indoor dust samples were collected from 3 cities, including Taiyuan (October 2016), Wuhan (October 2016 and 2018), and Shenzhen (February 2019), located in North, Central, and South China, for determination of the residues of six NNIs, two of their metabolites, and CBDZ. Acetamiprid (ACE), imidacloprid (IMI), and CBDZ were found to be the major target analytes in dust samples from all selected cities with detection frequencies of 98.8%, 99.7%, and 95.2%, respectively. At least one target NNI was detected for all of the dust samples, with the median concentration of 25.8 ng/g for the imidacloprid-equivalent total neonicotinoids (IMIeq: generated by the relative potency factor method), and the median for CBDZ was 35.8 ng/g. Higher levels of several NNIs and CBDZ were found in urban areas of Taiyuan and Wuhan than those in rural areas. A significant increase of the NNI residues was observed in dust of Wuhan from 2016 to 2018 (while not significant for CBDZ). Finally, the estimated daily intake (EDI) of IMIeq and CBDZ for infants and toddlers were higher than that found in other age groups through dust ingestion, which indicated that infants and toddlers may be susceptible to current residue of NNIs and CBDZ in indoor dust, and dust ingestion of NNIs might be <1% of that reported for dietary intakes in China. This is the first study to report the residue levels of NNIs and CBDZ in dust samples from indoor environment in China.


Assuntos
Poluição do Ar em Ambientes Fechados/análise , Benzimidazóis/análise , Carbamatos/análise , Poeira/análise , Monitoramento Ambiental , Neonicotinoides/análise , Poluição do Ar em Ambientes Fechados/estatística & dados numéricos , China
7.
Environ Int ; 130: 104876, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31344646

RESUMO

BACKGROUND: Pesticides exposures could be implicated in the excess of Central Nervous System (CNS) tumors observed in farmers, but evidence concerning individual pesticides remains limited. Carbamate derivative pesticides, including herbicides and fungicides (i.e. (thio/dithio)-carbamates), have shown evidence of carcinogenicity in experimental studies in animals. In the French AGRICAN cohort, we assessed the associations between potential exposures to carbamate herbicides and fungicides and the incidence of CNS tumors, overall and by histological subtype. METHODS: AGRICAN enrolled 181,842 participants involved in agriculture. Incident CNS tumors were identified by linkage with cancer registries from enrollment (2005-2007) until 2013. Individual exposures were assessed by combining information on lifetime periods of pesticide use on crops and the French crop-exposure matrix PESTIMAT, for each of the 14 carbamate and thiocarbamate herbicides and the 16 carbamate and dithiocarbamate fungicides registered in France since 1950. Associations were estimated using proportional hazard models with age as the underlying timescale, adjusting for gender, educational level and smoking. RESULTS: During an average follow-up of 6.9 years, 381 incident cases of CNS tumors occurred, including 164 gliomas and 134 meningiomas. Analyses showed increased risks of CNS tumors with overall exposure to carbamate fungicides (Hazard Ratio, HR = 1.88; 95% CI: 1.27-2.79) and, to a lesser extent, to carbamate herbicides (HR = 1.44; 95% CI: 0.94-2.22). Positive associations were observed with specific carbamates, including some fungicides (mancozeb, maneb, metiram) and herbicides (chlorpropham, propham, diallate) already suspected of being carcinogens in humans. CONCLUSIONS: Although some associations need to be corroborate in further studies and should be interpreted cautiously, these findings provide additional carcinogenicity evidence for several carbamate fungicides and herbicides.


Assuntos
Carbamatos/análise , Carcinógenos/análise , Neoplasias do Sistema Nervoso Central/epidemiologia , Fungicidas Industriais/análise , Glioma/epidemiologia , Herbicidas/análise , Meningioma/epidemiologia , Exposição Ocupacional/análise , Adulto , Idoso , Agricultura , Animais , Estudos de Coortes , Produtos Agrícolas , Monitoramento Ambiental , Feminino , França/epidemiologia , Humanos , Incidência , Masculino , Pessoa de Meia-Idade
8.
Ecotoxicol Environ Saf ; 182: 109395, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31272022

RESUMO

Adding organic amendments to soil could modify the bioavailability of herbicides and lead to changes in the microbial community's activity and structure. The objective here was to study the dissipation and total mass balance of 14C-labeled prosulfocarb applied at two rates (4 and 10 mg kg-1) in unamended and green compost (GC)-amended soil. Soil dehydrogenase activity (DHA) and phospholipid fatty acid (PLFA) profile analysis were determined to evaluate the effect of herbicide residues on microbial community's activity and structure over the dissipation period. The dissipation rate of prosulfocarb decreased after soil amendment due to higher herbicide adsorption by the amended soil. The 50% dissipation time (DT50) increased 1.7 times in the unamended soil when the concentration of prosulfocarb increased 2.5 times. The mass balance results indicate that the sum of water and organic extractable fractions represented the highest amounts up to the dissipation of 50% 14C-prosulfocarb. The 14C-herbicide was then mainly mineralized (up to 11%-31%) or formed non-extractable residues (up to 35%-44%). The amount of 14C-prosulfocarb residues extracted with methanol was slightly higher in amended soils than in unamended ones. 14C-prosulfocarb mineralization was higher in unamended soils than in amended ones. The formation of non-extractable residues was continuous, and increased over time. Soil DHA decreased in the unamended soil and was maintained in the GC-amended soil at the end of the assay. The microbial structure was barely disturbed over the prosulfocarb degradation process, although it was clearly influenced by the application of GC. The results obtained reveal the influence organic amendment has on herbicide bioavailability to decrease its biodegradation and buffer its impact on the soil microbial structure.


Assuntos
Carbamatos/análise , Herbicidas/análise , Poluentes do Solo/análise , Adsorção , Biodegradação Ambiental , Carbamatos/química , Compostagem , Herbicidas/química , Microbiota , Solo/química , Microbiologia do Solo , Poluentes do Solo/química
9.
Biosens Bioelectron ; 142: 111491, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31326864

RESUMO

A novel electrochemical sensor based on nitrogen and sulfur doped hollow Mo2C/C spheres (N, S-Mo2C) and molecularly imprinted polymer (MIP) was proposed for carbendazim (CBD) determination. The N, S-Mo2C were prepared by first nitrogen and sulfur doping via one-pot method and subsequent carbonization at high temperature. A film of MIP was then fabricated in situ on the N, S-Mo2C surface by electropolymerization, with CBD acting as template molecule and o-phenylenediamine as functional monomer. The N, S-Mo2C were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and electrochemical behaviors of CBD on differently modified electrodes were explored by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Under the optimal conditions, a calibration curve of current shift versus the logarithm of CBD concentration was obtained in the range of 1×10-12 ∼ 8×10-9 M with a detection limit of 6.7×10-13 M (S/N=3). Moreover, the proposed sensor exhibited favorable stability and selectivity, and was applied to analyze pesticide residues in fruits and vegetables with decent accuracy.


Assuntos
Benzimidazóis/análise , Carbamatos/análise , Técnicas Eletroquímicas/métodos , Molibdênio/química , Praguicidas/análise , Polímeros/química , Técnicas Biossensoriais/métodos , Espectroscopia Dielétrica/métodos , Eletrodos , Frutas/química , Limite de Detecção , Impressão Molecular/métodos , Nitrogênio/química , Fenilenodiaminas/química , Enxofre/química , Verduras/química
10.
Biomed Chromatogr ; 33(11): e4660, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31325166

RESUMO

In this study, a carboxyl group was introduced into the isoprocarb molecule to obtain an isoprocarb hapten, which was then coupled with a protein to obtain an artificial antigen. Three monoclonal antibody cell lines, 1D11, 6E6 and 1B5, were finally obtained by mouse immunization, cell fusion and subcloning, and the antibody produced by cell line 1B5 had the best affinity and sensitivity. The monoclonal antibody was highly sensitive and specific for isoprocarb, with an IC50 of 2.09 ng/ml and a cross-reactivity rate of <0.21%. By optimizing the indirect competitive (ic)-ELISA, the optimal conditions were determined to be pH 7.4, 0% methanol and 0.8% NaCl, the limit of detection value was 0.23 ng/ml, and the linear range of the ic-ELISA was 0.46-9.62 ng/ml. The recovery rate of the isoprocarb cucumber sample was 97-99% for the ic-ELISA method. In addition, we successfully developed an immunochromatographic test strip for the detection of isoprocarb residues. The cutoff values in phosphate-buffered saline and cucumber extract were 10 and 25 ng/ml, respectively. Both methods met the requirements for isoprocarb residue detection in agricultural products, and can be used for semiquantitative and qualitative analysis of isoprocarb in vegetables.


Assuntos
Anticorpos Monoclonais/metabolismo , Carbamatos/análise , Carbamatos/metabolismo , Ensaio de Imunoadsorção Enzimática/métodos , Imunoensaio/métodos , Especificidade de Anticorpos , Carbamatos/química , Coloide de Ouro/química , Limite de Detecção , Modelos Lineares , Reprodutibilidade dos Testes
11.
Spectrochim Acta A Mol Biomol Spectrosc ; 220: 117088, 2019 Sep 05.
Artigo em Inglês | MEDLINE | ID: mdl-31158606

RESUMO

A novel fluorescence application for simultaneous determination of two common fungicide pesticides (carbendazim and chlorothalonil) in peanut oil is presented. Using the strategy of combining excitation-emission matrix (EEM) fluorescence with three-way calibration methods, the proposed approach successfully achieved quantitative analysis of carbendazim and chlorothalonil pesticide residues in peanut oil, even with highly overlapped spectra. It needs little preparation, using "mathematical separation" instead of "analytical separation" to achieve concentration prediction of target analytes in complex systems. Each analyte was performed using fluorescence spectroscopy after instrument spectral correction and scatter removal. Then the data were modeled with two three-way calibration algorithms, including alternating trilinear decomposition (ATLD) and alternating penalty trilinear decomposition (APTLD). The results indicated that APTLD performed slightly better than ATLD for this system. The carbendazim and chlorothalonil can be recognized simultaneously with the correlation coefficients all above 0.96 between resolved spectra and actual spectra. Satisfactory results have been achieved with the average recoveries (mean ±â€¯standard deviation) of carbendazim and chlorothalonil being 100.2 ±â€¯6.7% and 99.7 ±â€¯6.7%, respectively. Moreover, as for carbendazim and chlorothalonil, the sensitivity (SENs) are 1.50 × 102 and 3.80 × 102 mL ng-1, the limits of detection (LODs) are 11 ng mL-1 and 4.3 ng mL-1, the limit of quantitation (LOQ) are 33.33 ng mL-1 and 13.03 ng mL-1, respectively. The above results demonstrated that the proposed method is sensitive, fast and accurate for direct quantitative analysis of multiple pesticide residues in complex matrix such as that of peanut oil.


Assuntos
Benzimidazóis/análise , Carbamatos/análise , Contaminação de Alimentos/análise , Nitrilos/análise , Óleo de Amendoim/análise , Espectrometria de Fluorescência/métodos , Algoritmos , Calibragem , Análise de Alimentos/métodos , Limite de Detecção , Resíduos de Praguicidas/análise , Reprodutibilidade dos Testes , Processamento de Sinais Assistido por Computador
12.
Food Chem ; 293: 271-277, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151611

RESUMO

The contamination of pesticide residues in Oolong tea has raised much concern in recent years. The objective of this study was to synthesize gold nanoparticles (AuNPs) and develop surface-enhanced Raman spectroscopy (SERS) methods for detection and quantification of pesticides in Oolong tea. Facile synthesis of spherical and monodispersed AuNPs with an average diameter of 15 nm was achieved, which induced strong electromagnetic fields in SERS analysis. AuNP substrates were employed for rapid detection and quantification of carbendazim in Tieguanyin Oolong tea. Partial least squares (PLS) analysis and leave-one-out cross validation were utilized in spectral data analysis. The PLS results for Oolong tea samples were obtained: R value = 0.964; the detection limit = 100 µg/kg. These results demonstrate that SERS coupled with gold nanoparticle substrate is a simple, rapid, and sensitive analytical tool for measurement and quantification of carbendazim residues in Oolong tea.


Assuntos
Benzimidazóis/análise , Carbamatos/análise , Ouro/química , Nanopartículas Metálicas/química , Resíduos de Praguicidas/análise , Praguicidas/análise , Análise Espectral Raman/métodos , Chá/química , Cor , Limite de Detecção
13.
J Environ Sci Health B ; 54(8): 702-708, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31112093

RESUMO

Benomyl is a benzimidazol fungicide used against various crop pathogens. Although banned in many countries, it is still widely used worldwide and is listed in different monitoring programs among the substances to be monitored to assess human exposure to pesticide residues. The assessment of benomyl is mainly based on the analysis of the residues of its most important metabolite, carbendazim. Existing methods often lack of selectivity and display a limited performance because of the presence of co-extracted compounds. Molecularly imprinted polymers (MIPs) offer an alternative methodology, adsorbing preferentially those target molecules for which the polymers are specifically prepared. In this study, we optimized the synthesis of a polymer imprinted with benomyl. Tests of specificity recognition showed a good performance for carbendazim compared with other similar pesticides. The mean recovery of benomyl (measured as carbendazim) from water samples was estimated to be 90% for MIPs while with real soil samples collected in Morocco the recovery efficiency was 62%. Preliminary tests also suggest that this MIP can implement traditional SPE techniques for assessing benomyl residual concentrations in environmental samples.


Assuntos
Benomilo/análise , Polímeros/química , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Adsorção , Benzimidazóis/análise , Carbamatos/análise , Fungicidas Industriais/análise , Impressão Molecular , Marrocos , Polímeros/síntese química , Extração em Fase Sólida/métodos
14.
Toxicol Mech Methods ; 29(7): 518-530, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31099292

RESUMO

In this study, an analytical strategy to identify brucine, strychnine, methomyl, carbofuran (alkaline compounds), phenobarbital, and warfarin (acid compounds) using thin-layer chromatography (TLC) screening with ultraviolet (UV) detection at 254 nm in stomach content is shown. The optimum mobile phase was found to be a chloroform: ethyl acetate: diethylamine (0.5:8.5:1) mixture for alkaline substances while a mixture of chloroform: acetone (9:1) has given better results for acidic substances. As for extraction, an equal proportion between distillated water and crude material (1:1) is required. For alkaline compounds, a filtration system was created in order to avoid any interferences from the biological matrix while for acidic compounds only centrifugation (4000 rpm/10 minutes) was required to obtain an appropriate sample. After the respective pretreatments, a one-step liquid-liquid extraction (LLE) has been employed for alkaline substances using a 3 mL of chloroform: ethyl ether (2:1) mixture for 2 min while acidic analytes used 3 mL of chloroform only during 5 min. For both methodologies described, the respective organic layers were dried down and re-suspended with 50 µL of methanol for further TLC plate application. The methodologies have been developed, successfully validated and applied to gastric contents from real case samples of suspected animal poisoning. Positive results from TLC/UV screening were confronted with HPLC-UV and confirmed by GC-MS.


Assuntos
Alcaloides/análise , Carbamatos/análise , Conteúdo Gastrointestinal/química , Fenobarbital/análise , Envenenamento/veterinária , Varfarina/análise , Alcaloides/envenenamento , Animais , Carbamatos/envenenamento , Doenças do Gato/induzido quimicamente , Gatos , Cromatografia em Camada Delgada/veterinária , Doenças do Cão/induzido quimicamente , Cães , Fenobarbital/envenenamento , Envenenamento/etiologia , Varfarina/envenenamento
15.
Regul Toxicol Pharmacol ; 106: 1-6, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31009652

RESUMO

Residues and dietary risk assessment of tetraconazole and bifenazate were investigated in strawberry under greenhouse conditions using high performance liquid chromatography (HPLC-DAD) after QuEChERs extraction in Beijing of China. The effects of different processing factors on the two pesticides were studied. The recoveries of tetraconazole and bifenazate were 87.0% and 89.1%, respectively. The dissipation curves of tetraconazole and bifenazate were in accordance with the first-order kinetic equation and the half-life were 5.92 d and 5.58 d, respectively. When the pre-harvest interval (PHI) was 3 d, the risk quotient (RQs) of both pesticides was less than 100%. Although soaking was a poor way to remove the two pesticides and heating at high temperatures increases the concentration of both pesticides, the residues of two pesticides can be effectively removed by washing after soaking. The results of dietary intake assessment indicated that potential dietary risk caused by tetraconazole and bifenazate in strawberry were acceptable for Chinese consumers.


Assuntos
Carbamatos/análise , Clorobenzenos/análise , Contaminação de Alimentos/análise , Fragaria/química , Hidrazinas/análise , Resíduos de Praguicidas/análise , Triazóis/análise , Adolescente , Adulto , Idoso , Carbamatos/efeitos adversos , Criança , Pré-Escolar , China , Clorobenzenos/efeitos adversos , Exposição Dietética , Feminino , Humanos , Hidrazinas/efeitos adversos , Masculino , Pessoa de Meia-Idade , Resíduos de Praguicidas/efeitos adversos , Medição de Risco , Triazóis/efeitos adversos , Adulto Jovem
16.
J Sep Sci ; 42(12): 2131-2139, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30977969

RESUMO

In this work, nanocomposites of reduced graphene oxide coated with ZnO were synthesized using a hydrothermal reduction strategy. Nanocomposite was then used as a sorbent for microextraction in a packed syringe, and its application to the extraction of carbamate pesticides from juice samples prior to high-performance liquid chromatography detection was demonstrated. Factors affecting the enrichment efficiency of the microextraction in a packed syringe procedure were optimized, which included desorption conditions, sample pH, salting-out effect, washing solution, and sample cycles. Under optimal conditions, the prepared materials exhibited excellent enrichment efficiency for carbamate pesticides. Good linearity existed in the concentration range of 0.5-200 ng/mL, with correlation coefficients of 0.9991-0.9997. The limits of detection of these carbamate pesticides were in the range of 0.23-1.21 ng/mL, and the average recoveries of the analytes at two spiked levels for real-sample analysis ranged from 90.5 to 104.2% with relative standard deviations of 3.6-5.9%.


Assuntos
Carbamatos/análise , Contaminação de Alimentos/análise , Sucos de Frutas e Vegetais/análise , Praguicidas/análise , Embalagem de Alimentos , Grafite/química , Microextração em Fase Líquida , Nanocompostos/química , Seringas , Óxido de Zinco/química
17.
J Colloid Interface Sci ; 546: 92-100, 2019 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-30904688

RESUMO

We reported a carbon nanohorns/gold nanoparticles composites-based impedimetric aptasensor for carbendazim (CBZ) detection in lettuce and orange juice at picogram levels. The increased electron-transfer resistance, resulting from the formation of CBZ-aptamer complex, was recorded by electrochemical impedance spectroscopy as the aptasensor response for CBZ. Under the optimal conditions, the proposed aptasensor displayed a linear response for CBZ ranging from 1 to 1000 pg mL-1 with a detection limit of 0.5 pg mL-1. Noteworthy, the as-developed aptasensor displayed the lowest detection limit for CBZ among the previously reported methods. Common pesticides (atrazine, thiamethoxam, etc.) with 100-fold concentration did not interfere the CBZ detection. For CBZ detection in lettuce and orange juice, satisfactory recoveries were obtained with standard addition method. Statistics demonstrated that no significant differences were found between the data provided by standard HPLC-MS reference method and developed aptasensing method in term of accuracy and precision. We believe that the proposed aptasensor possesses a potential application for CBZ monitoring in agricultural product and food.


Assuntos
Aptâmeros de Nucleotídeos/química , Benzimidazóis/análise , Carbamatos/análise , Carbono/química , Ouro/química , Nanopartículas/química , Técnicas Biossensoriais , Impedância Elétrica , Técnicas Eletroquímicas , Tamanho da Partícula , Propriedades de Superfície
18.
J Environ Sci Health B ; 54(5): 345-356, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30773128

RESUMO

Contaminants belonging to various classes, as polychlorobiphenyls, polycyclic aromatic hydrocarbons, organochlorine pesticides, organophosphorous pesticides, pyrethroid insecticides, fungicides, herbicides, synergists, carbamates, acaricides and insect growth regulators were simultaneously analysed by GC-MS/MS in 118 Italian and Tunisian culinary herbs and spices. The results obtained in Italian samples shown that laurel samples were the most contaminated with the presence of 15 residues on 140, whereas in rosemary (max value of 35 ng/g for cis-chlorfenyvinphos) and oregano (max value of 118.16 ng/g for ethion) some occasional residues can be observed, but always lower than the maximum residue levels; all the others samples shown no contamination. Among Tunisian samples, only rosemary contains a notably high content of pollutants exceeded the EU maximum residue limits (i.e., alachlor and phosalone with level of 359.2 and 43.3 ng/g, respectively), while oregano was determined to be free of contaminant residues. Considering the comparison among the different organic pollutants in Italian and Tunisian spices and herbs evaluated and the differences observed in this study a harmonization of regulation on contaminant residues in herbs and spices for human consumption should be needed, considering their increased use in diet and cooking.


Assuntos
Contaminação de Alimentos/análise , Praguicidas/análise , Especiarias/análise , Carbamatos/análise , Análise de Alimentos/métodos , Cromatografia Gasosa-Espectrometria de Massas , Hidrocarbonetos Clorados/análise , Itália , Origanum/química , Bifenilos Policlorados/análise , Piretrinas/análise , Espectrometria de Massas em Tandem , Tunísia
19.
Talanta ; 196: 537-545, 2019 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-30683402

RESUMO

Fast sampling and multicomponent detections are important in the analysis of pesticide residues detection. In this work, surface-enhanced Raman scattering (SERS) method based on silver-coated gold nanoparticles (Au@Ag NPs) was used to simultaneously detect multi-class pesticide residues such as thiacloprid (carbamate), profenofos (organophosphate) and oxamyl (neonicotinoid) in standard solution and peach fruit. The Au@Ag NPs with 26 nm Au core size and 6 nm Ag shell thickness exhibited significant Raman enhancement, especially by the creation of hot spots through NPs aggregation induced by the connection between Au@Ag NPs and target molecules. The findings demonstrated that the characteristic wavenumber of the pesticides (thiacloprid, profenofos, and oxamyl) could be precisely identified using the SERS method. Compared with earlier studies, the current approach was rapid, inexpensive and without lengthy sample pretreatment. Moreover, the results revealed that the limit of detection (LOD) was 0.1 mg/kg for thiacloprid obtained in the peach extract with determination coefficient (R2) of 0.986. Additionally, LOD for both profenofos and oxamyl was 0.01 mg/kg with a determination coefficient (R2) of 0.985 and 0.988, respectively. Good recovery percentage (78.6-162.0%) showed the high SERS activity with better accuracy for the detection of the thiacloprid, profenofos, and oxamyl in peach. The results of this study could offer a promising SERS platform for simultaneous detection of other contaminants such as thiacloprid, profenofos and oxamyl in multifaceted food matrices.


Assuntos
Frutas/química , Ouro/química , Inseticidas/análise , Nanopartículas Metálicas/química , Resíduos de Praguicidas/análise , Prunus persica , Prata/química , Carbamatos/análise , Carbamatos/química , Contaminação de Alimentos/análise , Inseticidas/química , Neonicotinoides/análise , Neonicotinoides/química , Organotiofosfatos/análise , Organotiofosfatos/química , Resíduos de Praguicidas/química , Análise Espectral Raman , Tiazinas/análise , Tiazinas/química
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 213: 159-166, 2019 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-30685554

RESUMO

Sofosbuvir (SOF) and velpatasvir (VEL) are recently co-formulated together for the treatment of hepatitis C virus. Smart and robust spectrophotometric methods were first developed and validated for quantification of SOF and VEL in their pure forms and in their combined pharmaceutical formulation without preliminary separation. VEL has two UV maxima at 302.5 and 337.0 nm that allow its direct determination by zero-order spectrophotometric method (D°) without any interference from SOF in a linear range of 2.0-30.0 µg/mL. On the other hand, determination of SOF in presence of VEL was carried out by four smart spectrophotometric methods, developed for resolving the overlaid spectra of these binary mixture. These methods are dual wavelength (DW), ratio subtraction (RS), ratio difference (RD) and first derivative of ratio spectra method (1DD). Linearity was checked and found to be in the range of 5.0-90.0 µg/mL for SOF by all of the aforementioned spectrophotometric methods. The developed methods were optimized and validated in accordance to the ICH guidelines. They were successfully utilized for estimating both SOF and VEL in their pure forms, laboratory prepared mixtures and in their pharmaceutical formulations with good recoveries. The methods can be easily applied for the routine analysis in quality control laboratories.


Assuntos
Antivirais/análise , Carbamatos/análise , Composição de Medicamentos , Compostos Heterocíclicos de 4 ou mais Anéis/análise , Sofosbuvir/análise , Espectrofotometria/métodos , Análise de Variância , Carbamatos/química , Cromatografia Líquida de Alta Pressão , Compostos Heterocíclicos de 4 ou mais Anéis/química , Limite de Detecção , Padrões de Referência , Análise de Regressão , Reprodutibilidade dos Testes , Sofosbuvir/química
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