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1.
J Agric Food Chem ; 67(40): 11244-11255, 2019 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-31532667

RESUMO

Evaluation of acetylcholinesterase (AChE) activity and determination of organophosphorus pesticides (OPs) are of great importance for the clinical diagnosis of several serious diseases correlated with their variations in human blood serum. In this study, a highly selective and sensitive ratiometric fluorescent probe was innovatively fabricated for the evaluation of AChE activity and the determination of OPs in tap water and food on the basis of the inner filter effect (IFE) between nitrogen-doped carbon dots (N-CDs) and 2,3-diaminophenazine (DAP). N-CDs were synthesized via a one-pot hydrothermal method by using pancreatin and 1,2-ethanediamine as precursors. N-CDs showed excellent fluorescence properties and negligible cytotoxicity on human cervical carcinoma HeLa cells and human embryonic kidney 293T cells, suggesting their further biological applications. Upon the addition of AChE and choline oxidase, acetylcholine was catalyzed to produce choline that was further oxidized to produce H2O2. In the presence of horseradish peroxidase, o-phenylenediamine reacted with H2O2 to produce fluorescent DAP. Therefore, a ratiometric fluorescent probing platform existed via IFE between N-CDs with a fluorescence signal at 450 nm and DAP with a fluorescence signal at 574 nm. OPs irreversibly impeded the catalytic activity of AChE, finally leading to the decrease of DAP amount and the variation of ratiometric fluorescent signal. Under optimal conditions, such a fluorescent probe showed relatively low detection limits of 0.38 U/L for AChE, 3.2 ppb for dichlorvos, and 13 ppb for methyl-parathion. Practical application of this ratiometric fluorescent probe to detect OPs was further verified in tap water and food samples with satisfying results that were highly consisted with the results obtained by GC-MS.


Assuntos
Acetilcolinesterase/química , Técnicas Biossensoriais/métodos , Carbono/química , Corantes Fluorescentes/química , Contaminação de Alimentos/análise , Compostos Organofosforados/análise , Praguicidas/análise , Poluentes Químicos da Água/análise , Fluorescência , Água Doce/análise , Células HeLa , Humanos , Limite de Detecção , Pontos Quânticos/química
2.
Environ Pollut ; 253: 120-129, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31302398

RESUMO

Flame retardants (FRs), such as brominated flame retardants (BFRs) and organophosphorus flame retardants (OPFRs), are diverse groups of compounds used in various products related to the indoor environment. In this study concentrations of eight polybrominated diphenyl ethers (PBDEs), two alternative BFRs and ten OPFRs were determined in indoor dust (n = 20) and pet cat hair (n = 11) from South Africa. The OPFRs were the major FRs, contributing to more than 97% of the total FR concentration. The median Ʃ10OPFRs concentrations were 44,800 ng/g in freshly collected dust (F-dust), 19,800 ng/g in the dust collected from vacuum cleaner bags (V-dust), and 865 ng/g in cat hair (C-hair). Tris(1-chloro-2-propyl) phosphate (TCIPP) was the dominant OPFR in the dust samples with median concentrations of 7,010 ng/g in F-dust and 3,590 ng/g in V-dust. Tris(2-butoxyethyl) phosphate (TBOEP) was the dominant OPFR in C-hair, with a median concentration of 387 ng/g. The concentrations of Ʃ8PBDEs were higher in F-dust than in V-dust. BDE209 was the dominant BFR in all three matrices. Bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP) and 2-ethylhexyl-2,3,4,5- tetrabromobenzoate (EH-TBB) showed notable contributions to the BFR profile in cat hair. A worst-case dust exposure estimation was performed for all analytes. The estimated TCIPP daily intake through dust ingestion was up to 1,240 ng/kg bw for toddlers. The results indicate that OPFRs are ubiquitous in South African indoor environment. Indoor dust is a major source of human exposure to environmental contaminants. This can for example occur through hand-to-mouth contact of toddlers, and is an important route of exposure to currently used FRs accumulated on dust particles. The presence of FRs, in particular high concentrations of OPFRs, suggests that children and indoor pet cats may have greater exposure to FRs than adults.


Assuntos
Retardadores de Chama/análise , Cabelo/química , Compostos Organofosforados/análise , Adulto , Poluição do Ar em Ambientes Fechados/análise , Animais , Gatos , Pré-Escolar , Poeira/análise , Monitoramento Ambiental , Éteres Difenil Halogenados/análise , Halogenação , Humanos , Organofosfatos/análise , Fosfatos/análise , Ácidos Ftálicos , África do Sul
3.
J Environ Sci Health B ; 54(7): 539-548, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31264931

RESUMO

Glyphosate (GLP) currently is one of the most widely used herbicides worldwide. The persistence of GLP and its major metabolite, aminomethylphosphonic acid (AMPA) in the environment has been described by other authors. This study was aimed at comparing the GLP and AMPA behavior in sandy and loamy sand soils after spiking with enhanced (445 µg g-1) concentrations of GLP in herbicide KLINIK® (Nufarm, Austria) and bioaugmentation followed by 40 days weathering and a consistent three-stage leaching in a laboratory column experiment. Soil samples were obtained from mineral topsoil (0-10 cm) within former agricultural lands where soil parent material was formed by glacigenic deposits. The total amount of GLP and AMPA collected during three leaching stages was significantly (p<.05) higher from columns with sandy soil, compared to loamy sand soil. Bioaugmentation resulted in considerably lower concentrations of AMPA in leachates, especially in the sets with sandy soil (p=.01). Leachates were tested using FTIR spectroscopy and Daphnia magna. Statistical analysis of the changes in Ntot, Ctot, K+, Mg2+, Al3+, Ca2+, Mn2+ and Fe3+ concentrations in soils after the leaching experiment revealed that the loamy sand soil was likely to be more sensitive to the addition of GLP and bioaugmentation than sandy soil.


Assuntos
Glicina/análogos & derivados , Poluentes do Solo/análise , Solo/química , Agricultura , Animais , Daphnia/efeitos dos fármacos , Glicina/análise , Glicina/química , Glicina/toxicidade , Herbicidas/análise , Herbicidas/química , Isoxazóis/análise , Compostos Organofosforados/análise , Compostos Organofosforados/química , Poluentes do Solo/química , Poluentes do Solo/toxicidade , Espectroscopia de Infravermelho com Transformada de Fourier , Tetrazóis/análise , Testes de Toxicidade
4.
Artigo em Inglês | MEDLINE | ID: mdl-31192775

RESUMO

The exposure to several compounds such as polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), organophosphorus pesticides (OPs), polycyclic aromatic hydrocarbon (PAHs), perfluoroalkyl substances (PFASs) and polybrominated diphenyl ethers (PBDEs) is a public health issue. The European Union (EU) recommended that its member states monitor the presence of emerging contaminants, like PBDEs and PFASs, in food and in the environment to obtain an accurate estimation of exposure. The tissues of wild animals exposed to these compounds can represent a suitable indicator of environmental pollution. The aim of this work is to evaluate: (i) the occurrence of PCBs, PBDEs, PFASs, PAHs, OCPs and OPs in four game animals' meat (chamois, red deer, wild boar and roe deer); (ii) interspecies differences and (iii) human exposure. Muscle samples from seventy-nine animals were collected during the hunting season in a Northern Italy mountain area at altitudes ranging from 300 to 2500 meters above sea level. The analyses were performed with gas chromatography-mass spectrometry (GC-MS/MS) and ultra-performance liquid chromatography - tandem mass spectrometry (UHPLC-MS/MS). No PBDEs were found in the samples. OCPs, OPs and PCBs were detected in almost all samples at different concentration ranges, showing higher frequency in ungulate species than in wild boar. PFAs were found only in wild boar. Anthracene and benzopyrene, among PAHs, were found only in chamois, at low concentrations. The lack of an accurate pattern of exposure as well as variable consumption by hunters does not allow accurate risk characterisation. However, a low risk for consumers can be indicated due to the frequent detection of contaminants only at trace levels, the scarce prevalence of high concentrations of some contaminants and the low consumption of game animal meat. In conclusion, the organisation of a control plan on residues in game animals would be advisable.


Assuntos
Animais Selvagens , Hidrocarbonetos Halogenados/análise , Inseticidas/análise , Carne/análise , Compostos Organofosforados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Animais , Cromatografia Líquida de Alta Pressão , Itália , Especificidade da Espécie , Espectrometria de Massas em Tandem
5.
Mar Pollut Bull ; 144: 140-145, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31179980

RESUMO

Shrimps are the most widely and increasingly cultured crustaceans in land-based ponds in Taiwan. However, few studies have investigated the phthalate contamination of and insecticide residues in shrimp. In this study, we applied a validated method to analyze the phthalate and 18 insecticides residues in shrimp. A total of 46 samples of whiteleg, grass, or giant river shrimp were collected from aquafarms and production areas in Taiwan. We detected 0.02-0.70 mg/kg of di-2-ethylhexyl phthalate (DEHP) in three shrimps; 0.02-0.03 mg/kg of chlorpyrifos in three shrimps, and 0.03 mg/kg of trichlorfon in one shrimp, indicating that 6.52% and 8.70% of the samples contained phthalate and insecticide residues, respectively. Furthermore, the assessed risk was negligible and indicated no immediate health risk associated with shrimp consumption. Continual monitoring of the residues in shrimps is critical for further assessment of possible effects on human health.


Assuntos
Inseticidas/análise , Compostos Organofosforados/análise , Penaeidae/química , Resíduos de Praguicidas/análise , Ácidos Ftálicos/análise , Poluentes Químicos da Água/análise , Animais , Aquicultura , Cromatografia Líquida , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Medição de Risco , Taiwan , Espectrometria de Massas em Tandem
6.
Chem Commun (Camb) ; 55(52): 7482-7485, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-31184653

RESUMO

Protein arginine (Arg) phosphorylation regulates stress responses and virulence in bacteria. With fluorescent activity probes, we show that McsB, a protein Arg kinase, can dephosphorylate phosphoarginine (pArg) residues to produce ATP from ADP, implicating the dynamic control of protein pArg levels by the kinase even without a phosphatase.


Assuntos
Arginina Quinase/metabolismo , Corantes Fluorescentes/química , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Arginina/análogos & derivados , Arginina/análise , Arginina/química , Arginina/metabolismo , Cromatografia Líquida de Alta Pressão , Compostos Organofosforados/análise , Fosforilação
7.
J Chromatogr A ; 1601: 357-364, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31104848

RESUMO

Glyphosate, a widely used herbicide, has been classified as probably carcinogenic to humans by the International Agency for Research on Cancer (IARC). In the present study a method based on Field-Amplified Sample Injection and Sweeping Micellar Electrokinetic Chromatography (FASI sweep-MEKC) has been developed and validated for determination of glyphosate and its microbial metabolite aminomethylphosphonic acid (AMPA) in wheat flour. The method involved a preliminary solid phase extraction for cleanup of the aqueous extracts from wheat flour, based sequentially on C18 and strong anion exchange cartridges, followed by derivatization using 9-fluorenylmethylchloroformate. Optimization of sample cleanup and derivatization procedure was carried out by a HPLC-UV method, whereas FASI sweep-MEKC was applied for achieving the sensitivity necessary for analysis of real samples. To this regard, optimum conditions involved the use of an extended path fused-silica capillary (80 cm total length, 50 µm, i.d.) filled with a high concentration buffer (sodium phosphate 100 mM, pH 2.2). Electrokinetic sampling was carried out at -10 kV with injection time of 700 s and the separation of the loaded analytes was performed under MEKC conditions using sodium phosphate buffer 50 mM at pH 2.2, supplemented with sodium dodecyl sulfate, 100 mM. The method was validated for linearity, precision, accuracy and sensitivity, showing that using conventional UV detection (210 nm) the achieved limit of quantitation (LOQ) values for both the analytes were widely lower than those set by Authorities. In particular, LOQ for glyphosate and AMPA were found to be 5 and 2.5 ng/mL, respectively, corresponding to 0.1 and 0.05 mg/kg, in wheat flour. The method, applied to commercially available real samples (wheat flour from different manufacturers) and to an experimental sample obtained by cv. Svevo wheat, can be considered as a convenient alternative to the existing approaches in analysis of complex matrices.


Assuntos
Cromatografia Capilar Eletrocinética Micelar , Glicina/análogos & derivados , Compostos Organofosforados/análise , Triticum/química , Glicina/análise , Isoxazóis , Dodecilsulfato de Sódio , Extração em Fase Sólida , Tetrazóis , Água/química
8.
J Agric Food Chem ; 67(22): 6133-6142, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-31067046

RESUMO

Glyphosate-based herbicide (GBH) applications were reported to induce physiological damages to glyphosate-resistant (GR) soybean, which were mainly attributed to aminomethylphosphonic acid (AMPA). In order to study glyphosate and AMPA dynamics in plants and associated phytotoxic effects, a greenhouse experiment was set where GR soybeans were exposed to GBH (0.7 to 4.5 kg glyphosate ha-1) and sampled over time (2, 7, 14, and 28 days after treatment (DAT)). Hydrogen peroxide content increased 2 DAT, while a decrease was observed for the effective quantum yield (2, 7, 14 DAT), stomatal conductance (2 DAT), and biomass (14 DAT). Glyphosate content was higher in leaves, followed by stems, and then roots. AMPA content tended to increase with time, especially in roots, and the amount of AMPA in roots was negatively correlated to mostly all phytotoxicity indicators. This finding is important since AMPA residues are measured in agricultural soils several months after GBH applications, which could impact productivity in GR crops.


Assuntos
Glicina/análogos & derivados , Resistência a Herbicidas , Herbicidas/análise , Compostos Organofosforados/análise , Soja/química , Glicina/análise , Glicina/metabolismo , Glicina/farmacologia , Herbicidas/metabolismo , Herbicidas/farmacologia , Compostos Organofosforados/metabolismo , Folhas de Planta/química , Folhas de Planta/efeitos dos fármacos , Folhas de Planta/metabolismo , Raízes de Plantas/química , Raízes de Plantas/efeitos dos fármacos , Raízes de Plantas/metabolismo , Caules de Planta/química , Caules de Planta/efeitos dos fármacos , Caules de Planta/metabolismo , Soja/efeitos dos fármacos , Soja/metabolismo
9.
Biosens Bioelectron ; 136: 112-117, 2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31054518

RESUMO

In this paper, we present a simple strategy to fabricate a sensitive fluorescence microfluidic sensor based on quantum dots (QDs) aerogel and acetylcholinesterase enzyme (AChE) for organophosphate pesticides (OPs) detection The detection is based on the change of fluorescence intensity of QDs aerogel, which will be partly quenched as a consequence of the hydrolytic reaction of acetylthiocholine (ATCh) catalyzed by the AChE, and then the fluorescence of QDs aerogel is recovered due to decreasing of the enzymatic activity in the presence of OPs. The QDs-AChE aerogel based microfluidic arrays sensor provided good sensitivity for rapid detection of OPs with a detection limit of 0.38 pM, while the detection range is from 10-5 to 10-12 M. Due to the result of random orientations of AChE in the 3D porous aerogel nano-structure, the sensor presents similar calibration curves to difference pesticides, which promises the ability of the sensor to monitor total OPs of mixture. This determination sensor shows a low detection limit, wide linear range, and highly accurate determination of total OPs and carbamate content. Finally, we show the proposed sensor can be used to monitor of simple OPs and mixture in spiked fruit samples. This novel QDs-AChE aerogel sensor has an extremely high sensitivity and large detection range, it is a promising tool for accurate, rapid and cost-effective detection of various OP residues on agricultural products.


Assuntos
Técnicas Biossensoriais/métodos , Frutas/química , Microfluídica/métodos , Compostos Organofosforados/análise , Praguicidas/análise , Acetilcolinesterase/química , Hidrogel de Polietilenoglicol-Dimetacrilato
10.
Sci Total Environ ; 683: 175-184, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31146057

RESUMO

A practical and efficient protocol for the derivatization and detection by GC-EI-MS of isopropyl-, pinacolyl- and cyclohexylmethylphosphonic acids, key diagnostic degradation products of the nerve agents sarin, soman and cyclosarin respectively, in six different types of soil matrices is presented. The method involves the in situ conversion of the phosphonic acids to their respective methyl esters using trimethyloxonium tetrafluoroborate when present in the soils at low levels (10 µg g-1) without any prior extractions or soil preparation. The soils employed in our study were Nebraska EPA soil, Georgia soil, silt, Virginia type A soil, regular sand and Ottawa sand and were chosen for their vast differences in composition and physical features. Appealing attributes of the protocol include its rapidity (t < 30 min), mildness (ambient temperature), and practicality that includes the production of the phosphonic methyl esters that can be easily detected by GC-EI-MS and corroborated with the instrument's internal NIST spectral library or the Organisation for the Prohibition of Chemical Weapons (OPCW) central analytical database (OCAD v.21_2019). The overall efficacy of the protocol was then tested on a soil sample featured in the 44th OPCW PT that our laboratory participated in. After preparing the soil so as to give pinacolyl methylphosphonic acid at a 5 µg g-1 concentration, the acid was successfully methylated and detected by GC-EI-MS. The protocol's performance mirrors that of the universally employed diazomethane protocol but accomplishes this without any of the explosive hazards and time consuming reagent preparation commonly associated with it.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos Organofosforados/análise , Poluentes do Solo/análise , Soman/análogos & derivados , Biomarcadores/análise , Metilação , Agentes Neurotóxicos/análise , Estudos Retrospectivos , Sarina/análise , Solo/química , Soman/análise
11.
Anal Chim Acta ; 1071: 1-7, 2019 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-31128750

RESUMO

Quantitatively paper-based senor is performed with simple distance-readout on mixed cellulose ester (MCE) filter paper based on acetylcholinesterase (AChE)-mediated alginate hydrogel. The method is accomplished with the aid of the inhibition effect of target samples on the AChE enzyme-catalyzed hydrolysis of acetylcholine, which changes the pH value of the solution to release Ca2+ and trigger alginate hydrogelation. The viscosity of the solution is thus regulated with the presence of target samples in the reaction mixture, leading to a significant change in the diffusion diameter of the solution spotted on the filter paper. The concentration in the sample is quantitatively determined by ruler-measureable diffusion diameter of the spot on the paper. With successfully application for quantitatively sensing of organophosphorus pesticides (OPs), we show that the method exhibits excellent reproducibility with RSD (n = 5) as low as 0.09% and good selectivity for detection of OPs. The dynamic range of the method is up to 66.7 ng/mL with the limit-of-detection (LOD) of 3.3 ng/mL. The present study provides a new approach for developing paper-based sensors with quantitative distance-readout, by utilizing enzymatic inhibition to modulate liquid viscosity, which would be of value for target detection in complex samples.


Assuntos
Acetilcolinesterase/química , Alginatos/química , Hidrogéis/química , Compostos Organofosforados/análise , Papel , Praguicidas/análise , Acetilcolina/química , Técnicas Biossensoriais/instrumentação , Técnicas Biossensoriais/métodos , Difusão , Contaminação de Alimentos/análise , Limite de Detecção , Malus/química , Reprodutibilidade dos Testes , Viscosidade
12.
J Chromatogr A ; 1599: 17-24, 2019 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-30987786

RESUMO

A headspace solid-phase microextraction (HS-SPME) method, involving solid-phase extraction and in-situ derivatization using polymeric thin film, was developed for the gas chromatography-mass spectrometry (GC-MS) analysis of the degradation products of nerve agents. The solid-phase extraction (SPE) was performed using poly([2-(Methacryloyloxy)ethyl]trimethylammonium chloride) film on a gold plate prepared via surface-initiated polymerization. The extracted analytes were directly derivatized with N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) on the plate. Various parameters like fiber type, headspace time, temperature, and amount of BSTFA were optimized. Under the optimized conditions, the relative standard deviations (RSDs) were in the range 7.0-13.1% and the limits of detection (LODs) were measured to be between 10 and 20 pg mL-1. The application of the developed method was tested using the 35th Organization for Prohibition of Chemical Weapons (OPCW) proficiency test sample.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Gasosa-Espectrometria de Massas , Compostos Organofosforados/análise , Polímeros/química , Microextração em Fase Sólida , Limite de Detecção , Agentes Neurotóxicos/química , Agentes Neurotóxicos/isolamento & purificação , Compostos Organofosforados/química , Microextração em Fase Sólida/instrumentação , Temperatura Ambiente
13.
Chemosphere ; 227: 409-415, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31003125

RESUMO

The concentrations and compositions of organophosphorus flame retardants (OPFRs) in various heat preservation materials from different brands and types in China were investigated, as well as their OPFR burdens and emission amounts. The average concentrations of ΣOPFRs were 41.4 ±â€¯10.2, (7.1 ±â€¯4.0) × 104, and 56.3 ±â€¯19.3 µg/g in phenolic foams (PF), polyurethane foams (PUR), and extruded polystyrene boards (XPS), respectively. OPFRs in the PUR materials were ∼3 orders of magnitude higher than those in the other two materials, suggesting that organophosphate esters were added as flame retardants (FRs) in the PUR materials. Obvious variations in the concentrations and compositions of OPFRs were discovered in those heat preservation materials due to their material types, brands, and fire-ratings, as well as contaminations. TCIPP was the most dominant OPFR with a range from 22.3 (in PF) to 6.73 × 104 (in PUR) µg/g, which emphasized that TCIPP was the most commonly used flame retardant additives in China. Based on the OPFR concentrations, OPFR emission rates, and application amounts of heat preservation materials, we calculated the total burdens of OPFRs in those materials and their emission amounts in China. The potential total burden of OPFRs in the completed new buildings of China in 2017 was estimated to be ∼(2.37 ±â€¯1.11) × 104 t, while the total emission of OPFRs from those new materials was ∼3.19 ±â€¯1.65 t/y. As significant sources of OPFRs, the heat preservation materials used in exterior or interior walls may pose potential health risks to humans.


Assuntos
Poluentes Ambientais/análise , Retardadores de Chama/análise , Organofosfatos/análise , Poliuretanos/química , China , Temperatura Alta , Humanos , Compostos Organofosforados/análise
14.
J Chromatogr A ; 1597: 214-219, 2019 Jul 19.
Artigo em Inglês | MEDLINE | ID: mdl-31010635

RESUMO

In this research an accumulation of nerve agent markers in garden cress (Lepidium sativum) as a model plant object was studied using LC-QTOF hybrid system. For the determination of methylphosphonic acid and alkyl methylphosphonates, which are specific markers of sarin, soman, VR and VX, simple and sensitive approach was developed. Direct analysis of aqueous extracts on the reversed phase column with polar endcapping allowed to achieve satisfactory retention factor for methylphosphonic acid, which has high polarity and is usually very weakly retained on the ordinary reversed phase columns. Application of the QTOF mass spectrometer with high mass resolution led to the increase in the accuracy of the conducted measurements. The HPLC-HRMS technique developed exclusively for this study has been validated for linearity, limit of detection, limit of quantification, precision, accuracy and matrix effect prior to the analysis of plant extract samples. Hydroponic growth model was employed to examine accumulation of nerve agent markers in garden cress. It was found that after elimination of nerve agent markers from the plant growth medium, garden cress was able to store these substances for at least 5 weeks providing high retrospectivity of the analysis. Moreover, during the cress growth, no metabolization of alkyl methylphosphonates was observed. This allows not only to reveal the fact of nerve agents release into environment, but also to define its type after a long period of time.


Assuntos
Biomarcadores Ambientais , Monitoramento Ambiental/métodos , Lepidium sativum/química , Agentes Neurotóxicos/análise , Cromatografia Líquida de Alta Pressão , Lepidium sativum/metabolismo , Agentes Neurotóxicos/metabolismo , Compostos Organofosforados/análise , Extratos Vegetais/química
15.
Ecotoxicol Environ Saf ; 179: 17-23, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31022651

RESUMO

A novel dual-mode analytical method by employing nanozyme was developed for the detection of organophosphorus pesticides (OPP) for the first time. The detection principle is that the pesticide could be hydrolyzed to para-nitrophenol (p-NP) in the presence of nanoceria as nanozyme. p-NP exhibits the bright yellow color, and its color intensity has a positive correlation with the pesticide concentration. Meanwhile, the characteristic absorption peak at 400 nm of p-NP increases gradually with the raised concentration of pesticide. Therefore, a dual-mode method including smartphone-based colorimetric and spectroscopic strategies was rationally developed. Herein, methyl-paraoxon was selected as the representative compound. Under the optimum conditions, the detection limits of both two strategies were calculated to be 0.42 µmol L-1. Finally, the present method was successfully applied in three edible medicinal plants (Semen nelumbinis, Semen Armeniacae Amarum, Rhizoma Dioscoreae). The present work offers a reliable and convenient approach for routine detection of pesticide based on two different detection mechanisms.


Assuntos
Cério/química , Poluentes Ambientais/análise , Nanopartículas/química , Compostos Organofosforados/análise , Praguicidas/análise , Plantas Medicinais/química , Colorimetria/métodos , Limite de Detecção , Nitrofenóis/química , Paraoxon/análogos & derivados , Paraoxon/análise , Espectrofotometria/métodos
16.
Analyst ; 144(10): 3436-3441, 2019 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-31020297

RESUMO

Organophosphorus pesticides (OPs) are widely used in agricultural fields, but exhibit high toxicity to human beings. A sensitive fluorescence assay for organophosphorus pesticides was developed using the inhibition of acetylcholinesterase (AChE) activity and the copper-catalyzed click chemical reaction. In the click reaction, two hybridized DNA probes can be ligated with copper ions, inducing a fluorescence quenching during the strand displacement reaction. AChE can hydrolyze acetylthiocholine (ATCh) to form thiocholine (TCh) which contains a thiol group. TCh will react with copper ions, blocking the click reaction and a high fluorescence signal is observed. But in the presence of OPs, the activity of AChE is inhibited, releasing a high concentration of copper ions that catalyze the click chemical reaction and resulting in decreased fluorescence signals. Taking advantage of the copper-mediated signal amplification effect, the sensitivity was improved. This assay has also been applied to detect OPs in river water samples with satisfactory results, which demonstrates that the method has great potential for practical applications in environmental protection and food safety fields.


Assuntos
Inibidores da Colinesterase/análise , Compostos Organofosforados/análise , Praguicidas/análise , Espectrometria de Fluorescência/métodos , Acetilcolinesterase/química , Acetiltiocolina/química , Catálise , Quelantes/química , Inibidores da Colinesterase/química , Química Click , Cobre/química , DNA/química , Sondas de DNA/química , Fluorescência , Corantes Fluorescentes/química , Limite de Detecção , Compostos Organofosforados/química , Praguicidas/química , Rios/química , Tiocolina/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/química
17.
J Chromatogr Sci ; 57(7): 606-617, 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-30994880

RESUMO

The analysis of degradation products from the classic chemical warfare nerve agents by high-performance liquid chromatography-mass spectrometry has been of much interest in recent years owing to the possible use as a terrorist weapon, and the incidents of chemical weapon usage in recent years in war torn countries. The alkyl methylphosphonic acid degradation products are of a particular interest, and they represent a specific chromatographic technical challenge for use in typical separation systems. Various published methods are summarized in this review and some of the problems associated with the analysis of these compounds are discussed. Future trends of the analysis in this area of research are also considered.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas/métodos , Agentes Neurotóxicos , Compostos Organofosforados , Agentes Neurotóxicos/análise , Agentes Neurotóxicos/química , Compostos Organofosforados/análise , Compostos Organofosforados/química
18.
Anal Chim Acta ; 1060: 97-102, 2019 Jul 04.
Artigo em Inglês | MEDLINE | ID: mdl-30902336

RESUMO

A portable and user-friendly method using personal glucose meters for on-site quantitative detection of organophosphorus pesticide (OP) was developed. The inhibition of organophosphorus compounds on acetylcholinesterase (AChE) leads to reduced yields of thiocholine formed by the enzymatic hydrolysis of acetylthiocholine chloride. Ferricyanide ([Fe(CN)6]3-), the mediator used in glucose test strips for electron transfer to the electrode, can be rapidly reduced to ferrocyanide ([Fe(CN)6]4-) by thiocholine. This reaction enables direct measurement of thiocholine by personal glucose meters in the same way as measuring the glucose in blood, offering an interesting choice to quantify OP. After incubation of AChE for 30 min and enzymatic reaction of 10 min, the yield of thiocholine was measured by a personal glucose meter, achieving detection limit of 5 µg L-1 for paraoxon. The proposed method was successfully applied to the detection in apples and cucumbers, presenting promising potential for on-site OP detection in food samples.


Assuntos
Técnicas Biossensoriais , Automonitorização da Glicemia , Compostos Organofosforados/análise , Praguicidas/análise , Tiocolina/química , Humanos
19.
Molecules ; 24(5)2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30813539

RESUMO

Here, we introduced a novel thiourea-based rhodamine compound as a chromo-fluorogenic indicator of nerve agent Soman and its simulant diethyl chlorophosphate (DCP). The synthesized probe N-(rhodamine B)-lactam-2-(4-cyanophenyl) thiourea (RB-CT), which has a rhodamine core linked by a cyanophenyl thiosemicarbazide group, enabled a rapidly and highly sensitive response to DCP with clear fluorescence and color changes. The detection limit was as low as 2 × 10-6 M. The sensing mechanism showed that opening of the spirolactam ring following the phosphorylation of thiosemicarbazides group formed a seven-membered heterocycle adduct, according to MS analysis and TD-DFT calculations. RB-CT exhibited high detecting selectivity for DCP, among other organophosphorus compounds. Moreover, two test kits were employed and successfully used to detect real nerve agent Soman in liquid and gas phase.


Assuntos
Corantes Fluorescentes/síntese química , Compostos Organofosforados/análise , Rodaminas/química , Soman/análise , Tioureia/química , Substâncias para a Guerra Química/análise , Substâncias para a Guerra Química/química , Corantes Fluorescentes/química , Limite de Detecção , Estrutura Molecular , Agentes Neurotóxicos/análise , Agentes Neurotóxicos/química , Compostos Organofosforados/química , Soman/química
20.
Environ Monit Assess ; 191(2): 119, 2019 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-30706205

RESUMO

This study developed a new method to determine the residues of 13 organophosphorus flame retardants (OPFRs) in drinking water by gas chromatography-tandem mass spectrometry (GC-MS/MS) technique and investigated the chemical distribution in water samples from municipal plants along the Yangtze River in Nanjing. The linear calibration correlation coefficients R2 for all 13 OPFRs were at least 0.998 0. Three levels of spiked test were performed. Most of the recoveries were in the range of 80~120%, and the relative standard deviations (RSDs) for the 13 OPFRs were 2.1~17% (n = 6). Five OPFRs were 100% positively detected in the samples, and 3 OPFRs were positively detected in some samples. The concentrations of detected OPFR in the water ranged from 0.7 to 5780.0 ng L-1. The average concentrations of OPFRs in wet season were higher than those in dry season, and the contaminants mainly originated from the source water in the Yangtze River. The exposure assessments of individual and total OPFRs were investigated. The estimated daily intakes of total OPFRs via ingestion of drinking water reached up to 64.8 and 45.2 ng/kg bw/day in dry and wet season, respectively. This study demonstrates a profile of OPFR distribution in Nanjing municipal water and provides information on human exposure assessment via drinking water in the Nanjing District, China.


Assuntos
Água Potável/análise , Monitoramento Ambiental/métodos , Retardadores de Chama/análise , Compostos Organofosforados/análise , Rios/química , Poluentes Químicos da Água/análise , China , Água Potável/normas , Humanos
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