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1.
Chemosphere ; 168: 418-425, 2017 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-27810542

RESUMO

The aim of this work was to determine the efficiency of a straw/compost/soil biomixture for pesticide depuration during its aging and continuous use, for a period of over a year, based on its capacity to remove carbofuran (CFN), while simultaneously monitoring the variations in microbial community structure. Successive CFN spikings were applied in the biomixture at 6-week intervals, and the removal efficiency was determined 48 h post-application. Initially, only a discrete degradation performance was observed (9.9%), but one CFN application was sufficient to induce efficient elimination (>88.5%) of the pesticide at subsequent influxes for a period of over 6 months. A statistically significant reduction on CFN removal efficiency after this time was detected, reaching levels similar to the fresh-prepared biomixture (14.8%) at the end of the experiment. Simultaneous DGGE analyses showed only modest changes on microbial community patterns through time for both, bacteria and fungi. The clustering of genetic fingerprints in chronological groups corresponding to significantly different CFN degradation efficiencies indicates that biomixture aging changes not only the composition of microbial communities, but also their suitability to engage in pesticide degradation. Periodic substitution of straw/compost/soil biomixture in biopurification systems or regular provision of easily-degradable organic substrates should be considered to maintain an adequate depuration capacity on this system.


Assuntos
Biodegradação Ambiental , Carbofurano/química , Microbiologia do Solo , Solo/química , Aldicarb/análise , Bactérias/metabolismo , Carbamatos/análise , DNA/análise , Eletroforese , Recuperação e Remediação Ambiental , Fungos/metabolismo , Metomil/análise , Resíduos de Praguicidas/análise , Praguicidas/análise , RNA Ribossômico 16S/análise , Poluentes do Solo/análise
2.
Exp Toxicol Pathol ; 68(6): 307-14, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-27020045

RESUMO

Exhumation is required for the investigation of suspicions deaths when a body is buried and is usually performed under court order. Exhumation of animals is not a routine practice in forensic pathology. In this study, 30 male 70-day-old Wistar rats were experimentally exposed to the carbamate pesticides aldicarb and carbofuran. Toxicological, macroscopic and microscopic examinations were performed. Groups of 3 animals (2 exposed and 1 control) were evaluated at 24h, 3days, 5days, 7days and 10days post-mortem. In histopathological examination, the brain, liver, lungs and kidneys were assessed, and for toxicological analysis, the gastric contents, liver, vitreous humor, skeletal muscle and larvae (when available) were collected. The pesticides were detected by HPLC and quantified in the analyzed matrices, and a possible delay in tissue putrefaction due to the pesticides was observed. This study has revealed that it is possible to exhume animals for investigations of possible poisoning by carbamates and has demonstrated that the exhumation of an animal in a suspected case of poisoning should not be ruled out. The increasing demand for investigations of suspicious animal deaths, e.g., in cases of poisoning, will likely lead to an increase in the use of this type of procedure in veterinary pathology.


Assuntos
Aldicarb/envenenamento , Carbofurano/envenenamento , Exumação/métodos , Inseticidas/envenenamento , Síndromes Neurotóxicas/veterinária , Aldicarb/análise , Animais , Carbofurano/análise , Cromatografia Líquida de Alta Pressão , Inseticidas/análise , Masculino , Ratos , Ratos Wistar
3.
Int J Legal Med ; 130(4): 981-983, 2016 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-26914800

RESUMO

Chumbinho is the popular name given to carbamate aldicarb (Temik), an insecticide commonly used in agriculture and highly toxic (LD50 = 0.9 mg/kg oral in rats) that has been sold clandestinely in several regions of Brazil. Chumbinho is sold illegally as raticide and is available in a formulation of small black granules which are easily mixed with food for criminal purposes, its use often being attributed to accidents and suicides, hence the importance of its inclusion in the toxicology studies of suspicious deaths. With the corpse putrefaction, many pathological and toxicological anatomical parameters are damaged or lost. This study emphasizes the importance of the gastric content observation, which in this case has, despite the advanced putrefaction, recognized the presence of chumbinho and guide its toxicological confirmation.


Assuntos
Aldicarb/envenenamento , Inseticidas/envenenamento , Mudanças Depois da Morte , Aldicarb/análise , Aldicarb/química , Cromatografia Gasosa-Espectrometria de Massas , Conteúdo Gastrointestinal/química , Humanos , Inseticidas/análise , Inseticidas/química , Masculino , Pessoa de Meia-Idade , Estrutura Molecular
4.
Biosens Bioelectron ; 77: 644-9, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26492468

RESUMO

Pesticides are of great importance in agricultural and biological fields, but pesticide residues may harm the environment and human health. A highly sensitive fluorescent biosensor for the detection of carbamate pesticide has been developed based on acetylcholinesterase (AChE)-catalyzed hydrolysis product triggered Hg(2+) release coupled with subsequent nicking enzyme-induced cleavage of a duplex DNA for cycling amplification. In this protocol, two DNA probes, an unmodified single-stranded helper DNA probe 1 (HP1) and a quencher-fluorophore probe (QFP) are ingeniously designed. HP1 can be folded into hairpin configuration through T-Hg(2+)-T base pair formation. QFP, labeled with FAM and BHQ1 at its two terminals, contains the recognition sequence and the cleavage site of the nicking enzyme. In the presence of carbamate pesticide, the activity of AChE is inhibited, and the amount of the product containing the thiol group generated by the hydrolysis reaction of acetylthiocholine chloride (ACh) decreases, resulting in the release of a low concentration of Hg(2+). The number of HP1 that can be selectively unfolded would be reduced and the subsequent nicking enzyme-assisted cleavage processes would be affected, resulting in decreased fluorescence signals. The fluorescence intensity further decreases with the increase of the pesticide concentration. Therefore, the pesticide content can be easily obtained by monitoring the fluorescence signal change, which is inversely proportional to the logarithm of the pesticide concentration. The detection limit of aldicarb, the model analyte, is 3.3 µgL(-1), which is much lower than the Chinese National Standards or those previously reported. The as-proposed method has also been applied to detect carbamate pesticide residues in fresh ginger and artificial lake water samples with satisfactory results, which demonstrates that the method has great potential for practical application in biological or food safety field.


Assuntos
Aldicarb/análise , DNA/química , DNA/ultraestrutura , Mercúrio/química , Praguicidas/análise , Espectrometria de Fluorescência/instrumentação , Carbamatos/análise , DNA/genética , Quebras de DNA de Cadeia Simples , Desenho de Equipamento , Análise de Falha de Equipamento , Técnicas de Amplificação de Ácido Nucleico/métodos , Conformação de Ácido Nucleico , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
5.
Talanta ; 144: 559-68, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26452862

RESUMO

New acetylcholinesterase (AChE) biosensor based on unsubstituted pillar[5]arene (P[5]A) as electron mediator was developed and successfully used for highly sensitive detection of organophosphate and carbamate pesticides. The AChE from electric eel was immobilized by carbodiimide binding on carbon black (CB) placed on glassy carbon electrode. The working potential of 200mV was obtained in chronoamperometric mode with the measurement time of 180 s providing best inter-biosensors precision of the results. The AChE biosensor developed made it possible to detect 1×10(-11)-1×10(-6) M of malaoxon, 1×10(-8)-7×10(-6) M of methyl-paraoxon, 1×10(-10)-2×10(-6) M of carbofuran and 7×10(-9)-1×10(-5) M of aldicarb with 10 min incubation. The limits of detection were 4×10(-12), 5×10(-9), 2×10(-11) and 6×10(-10) M, respectively. The AChE biosensor was tested in the analysis of pesticide residuals in spiked samples of peanut and beetroot. The protecting effect of P[5]A derivative bearing quaternary ammonia groups on malaoxon inhibition was shown.


Assuntos
Acetilcolinesterase/química , Técnicas Biossensoriais , Inibidores da Colinesterase/análise , Enzimas Imobilizadas/química , Inseticidas/análise , Resíduos de Praguicidas/análise , Aldicarb/análise , Aldicarb/química , Arachis , Beta vulgaris , Calixarenos , Carbodi-Imidas/química , Carbofurano/análise , Carbofurano/química , Carbono/química , Inibidores da Colinesterase/química , Eletrodos , Inseticidas/química , Malation/análogos & derivados , Malation/análise , Malation/química , Nozes/química , Paraoxon/análogos & derivados , Paraoxon/análise , Paraoxon/química , Resíduos de Praguicidas/química , Raízes de Plantas/química , Compostos de Amônio Quaternário/química
6.
Se Pu ; 32(6): 635-9, 2014 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-25269263

RESUMO

A simple and rapid pretreatment procedure was developed for the simultaneous determination of aldicarb and its metabolites, aldicarb sulfone and aldicarb sulfoxide in ginger. The samples were extracted with acetonitrile, and then cleaned up with multiplug filtration using multiwalled carbon nanotubes (MWCNTS). The eluate was dried with nitrogen gas at room temperature, and redissolved in an acetonitrile-water (5:95, v/v) mixture, then quantified by ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) operated in positive multiple reaction monitoring (MRM) mode. A linear relationship was achieved in the range of 0.5 -200 microg/L for the peak areas to the mass concentrations of the target compounds with the linear correlation coefficients (r2) higher than 0.99. The recoveries at three spiked levels of 2, 20 and 200 microg/kg were in the range from 71.4% to 89.8% with the relative standard deviations (RSDs, n = 6) from 0.7% to 13.2% under the selected conditions. The limits of quantification (LOQ, S/N = 10) of aldicarb, aldicarb sulfone, and aldicarb sulfoxide in ginger were 1.0, 2.0 and 1.0 microg/kg, respectively. The results demonstrate that the developed method is rapid, cost-effective, and can meet the requirements of the multiple pesticide residue analysis. The method is applicable to determine aldicarb and its metabolites in ginger.


Assuntos
Aldicarb/análogos & derivados , Gengibre/química , Resíduos de Praguicidas/análise , Aldicarb/análise , Nanotubos de Carbono , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem
7.
Talanta ; 127: 9-17, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-24913851

RESUMO

New acetylcholinesterase (AChE) sensor based on Ag nanoparticles decorated with macrocyclic ligand has been developed and successfully used for highly sensitive detection of organophosphate and carbamate pesticides. AChE was immobilized by carbodiimide binding on carbon black (CB) layer deposited on a glassy carbon electrode. The addition of Ag nanoparticles decreased the working potential of the biosensor from 350 to 50 mV. The AChE sensor made it possible to detect 0.4 nM-0.2 µM of malaoxon, 0.2 nM-0.2 µM of paraoxon, 0.2 nM-2.0 µM of carbofuran and 10 nM-0.20 µM of aldicarb (limits of detection 0.1, 0.05, 0.1 and 10 nM, respectively) with 10 min incubation. The AChE sensor was tested for the detection of residual amounts of pesticides in spiked samples of peanut and grape juice. The protecting effect of new macrocyclic compounds bearing quaternary ammonia fragments was shown on the example of malaoxon inhibition.


Assuntos
Acetilcolinesterase/química , Inibidores da Colinesterase/análise , Inseticidas/análise , Nanopartículas Metálicas/química , Prata/química , Aldicarb/análise , Aldicarb/química , Arachis/química , Bebidas/análise , Técnicas Biossensoriais , Calixarenos/química , Carbofurano/análise , Carbofurano/química , Carbono/química , Inibidores da Colinesterase/química , Eletrodos , Contaminação de Alimentos/análise , Frutas/química , Inseticidas/química , Malation/análogos & derivados , Malation/análise , Malation/química , Paraoxon/análise , Paraoxon/química , Compostos de Amônio Quaternário/química , Vitis
8.
Lab Chip ; 14(7): 1270-80, 2014 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-24463940

RESUMO

This paper presents a lab-on-chip biosensor containing an enclosed fluidic cell culturing well seeded with live cells for rapid screening of toxicants in drinking water. The sensor is based on the innovative placement of the working electrode for the electrical cell-substrate impedance sensing (ECIS) technique as the top electrode of a quartz crystal microbalance (QCM) resonator. Cell damage induced by toxic water will cause a decrease in impedance, as well as an increase in the resonant frequency. For water toxicity tests, the biosensor's unique capabilities of performing two complementary measurements simultaneously (impedance and mass-sensing) will increase the accuracy of detection while decreasing the false-positive rate. Bovine aortic endothelial cells (BAECs) were used as toxicity sensing cells. The effects of the toxicants, ammonia, nicotine and aldicarb, on cells were monitored with both the QCM and the ECIS technique. The lab-on-chip was demonstrated to be sensitive to low concentrations of toxicants. The responses of BAECs to toxic samples occurred during the initial 5 to 20 minutes depending on the type of chemical and concentrations. Testing the multiparameter biosensor with aldicarb also demonstrated the hypothesis that using two different sensors to monitor the same cell monolayer provides cross validation and increases the accuracy of detection. For low concentrations of aldicarb, the variations in impedance measurements are insignificant in comparison with the shifts of resonant frequency monitored using the QCM resonator. A highly linear correlation between signal shifts and chemical concentrations was demonstrated for each toxicant.


Assuntos
Aldicarb/análise , Amônia/análise , Técnicas Biossensoriais/métodos , Células Endoteliais/metabolismo , Dispositivos Lab-On-A-Chip , Nicotina/análise , Água/análise , Animais , Bovinos
9.
J Agromedicine ; 18(2): 174-7, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23540307

RESUMO

Improper use of pesticides on food plants can result in significant toxicity. In spite of regulations, enforcement, and prior episodes of poisonings, poisonings from misapplication of pesticides continues to occur. The objective of this study was to present a case series of toxicity resulting from ingestion of watermelon inappropriately treated with the carbamate insecticide aldicarb. A restrospective review of medical records, impounding the suspected watermelons, and chemical analysis of the watermelon samples using liquid chromatography and mass spectroscopy were carried out. Seven farm workers shared a watermelon and presented to a rural emergency department with symptoms of cholinergic poisoning. They were treated empirically with atropine and pralidoxime. The farmer denied use of insecticides other than rat poison on the watermelon patch. Chemical analyst verified aldicarb in the watermelon samples from the field, but none in control samples. Despite government regulations, application of restricted pesticides such as aldicarb continues to occur and cause significant poisonings.


Assuntos
Aldicarb/envenenamento , Citrullus/envenenamento , Contaminação de Alimentos/análise , Inseticidas/envenenamento , Administração Oral , Adulto , Aldicarb/administração & dosagem , Aldicarb/análise , Aldicarb/toxicidade , Atropina/uso terapêutico , Citrullus/química , Citrullus/toxicidade , Humanos , Inseticidas/análise , Inseticidas/toxicidade , Masculino , Pessoa de Meia-Idade , Envenenamento/tratamento farmacológico , Compostos de Pralidoxima/uso terapêutico , Estudos Retrospectivos , Adulto Jovem
10.
Analyst ; 138(2): 659-65, 2013 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-23181258

RESUMO

The electrospray ionization (ESI) is a complex process and there has been a long debate regarding the gas-phase effect on ion generation in the process. In this paper we investigated the effect of liquid chromatographic mobile phase additives (formic acid, aqueous ammonia and their combination) on the ESI signal intensities for a wide variety of compounds. The addition of a trace amount of aqueous ammonia to the common formic acid-methanol mobile phase significantly enhances the ESI signals of protonated molecules and suppresses the formation of sodium adduct ions. This effect is well observed for the compounds containing the -N-C=O group but not for those without N or O atoms. The ESI signal intensity of deprotonated molecules increases with increase in pH of the mobile phase for neutral compounds, such as substituted urea, whereas this trend is not observed for acidic compounds such as phenoxy acids. The mechanistic analysis regarding liquid- and gas-phase protonation and deprotonation is discussed.


Assuntos
Compostos de Amônio Quaternário/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Aldicarb/análise , Aldicarb/química , Atrazina/análise , Atrazina/química , Carbono/química , Formiatos/química , Concentração de Íons de Hidrogênio , Metanol/química , Nitrogênio/química , Oxigênio/química , Simazina/análise , Simazina/química
11.
Artigo em Inglês | MEDLINE | ID: mdl-22906968

RESUMO

The luminescence arising from lanthanide cations offers several advantages over organic fluorescent molecules: sharp, distinctive emission bands allow for easy resolution between multiple lanthanide signals; long emission lifetimes (µs-ms) make them excellent candidates for time-resolved measurements; and high resistance to photo bleaching allow for long or repeated experiments. A time-resolved (gated) luminescence-based method for determination of pesticides methomyl, aldicarb and prometryne in microtiterplate format using the long-lived terbium-3-carboxycoumarin in 1:3 metal:ligand ratio has been developed. The limit of detection is 1.20×10(6), 5.19×10(5) and 2.74×10(6)ng L(-1) for methomyl, prometryne and aldicarb, respectively. The quantum yield (QY=0.08) of Tb(III)-3-carboxycoumarin was determined using 3-(2-benzothiazolyl)-7-diethylamino-coumarin (coumarin 6). Stern-volmer studies at different temperatures indicate that collisional quenching dominates for methomyl, aldicarb and prometryne. Binding constants were determined at 303, 308 and 313 K by using Lineweaver-Burk equation. A thermodynamic analysis showed that the reaction is spontaneous with negative ΔG. Effect of some relevant interferents on the detection of pesticides has been investigated.


Assuntos
Aldicarb/análise , Cumarínicos/química , Luminescência , Metomil/análise , Sondas Moleculares/química , Compostos Organometálicos/química , Praguicidas/análise , Prometrina/análise , Térbio/química , Aldicarb/química , Disprósio/química , Gadolínio/química , Cinética , Limite de Detecção , Metomil/química , Praguicidas/química , Prometrina/química , Solventes/química , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta , Temperatura , Fatores de Tempo
12.
Se Pu ; 30(3): 309-13, 2012 Mar.
Artigo em Chinês | MEDLINE | ID: mdl-22715699

RESUMO

A high performance liquid chromatography-linear ion trap triple stage mass spectrometry (HPLC-IT/MS3) method was established to detect aldicarb, aldicarb sulfoxide, and aldicarb sulfone in peanuts. The samples were extracted by acetonitrile saturated with cyclohexane, followed by clean-up with gel permeation chromatography (GPC). The determination was performed using HPLC-IT/MS3 for the identification and quantification of the compounds. The separation was carried on a Capcell PAK CR column with gradient elution using 5 mmol/L acetic acid/ammonium acetate/acetonitrile as mobile phase. The ionization of molecules was performed by electrospray mode. Selective reaction monitoring (SRM) was the acquisition mode used for the monitoring of MS3 transitions for each compound using aldicarb-d3 as internal standard for three analytes. Matrix effects were evaluated by comparing the recovery of matrix-matched and solvent-based calibration curves. The calibration graphs were linear in the ranges of 10 - 500 microg/L and the detection limits ranged from 4 to 5 microg/kg. The average recoveries ranged between 81.5% and 115% at three different spiked levels (10, 20 and 40 microg/kg). Satisfactory results were obtained in the determination of real peanut samples by this method.


Assuntos
Aldicarb/análise , Arachis/química , Cromatografia Líquida de Alta Pressão , Safrol/análogos & derivados , Espectrometria de Massas por Ionização por Electrospray , Aldicarb/análogos & derivados , Aldicarb/metabolismo , Safrol/análise
13.
Drug Chem Toxicol ; 35(2): 192-8, 2012 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-21939365

RESUMO

Water is a necessity for life. Currently, because of different contaminations in tap water, most people prefer using bottled mineral waters. Pesticides (e.g., organophophorous, carbamates, etc.) are among the most dangerous chemicals that may be found in drinking waters, which can cause long- and short-term complications. Because all people consume at least 2 L of water per day, water-quality monitoring is vital. In this study, we determined the concentration of three pesticides (aldicarb, parathion, and thiobencarb) in 13 tap-water samples collected from 13 different urban areas and 10 samples of bottled mineral water in Mashhad, a major city in northeast Iran. Samples were analyzed by gas chromatography coupled with a pulsed flame photometric detector after solid-phase extraction. Results showed that 2 of 13 tap-water samples and 2 of 10 bottled mineral water trademarks were contaminated either by parathion or by thiobencarb or both, with concentrations ranging between 0.6 and 0.8 ppb. According to the defined guideline values, determined concentrations of pesticides are below the permissible World Health Organization level for these toxic agents, and it is considered that drinking these tap waters and bottled mineral waters are safe for human consumption.


Assuntos
Aldicarb/análise , Águas Minerais/análise , Paration/análise , Tiocarbamatos/análise , Poluentes Químicos da Água/análise , Abastecimento de Água/análise , Inibidores da Colinesterase/análise , Cromatografia Gasosa , Herbicidas/análise , Humanos , Inseticidas/análise , Irã (Geográfico) , Extração em Fase Sólida , População Urbana , Abastecimento de Água/normas
14.
Anal Chim Acta ; 671(1-2): 41-7, 2010 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-20541641

RESUMO

Using a 2(3) experimental design, liquid-liquid extraction with low temperature partitioning (LLE-LTP) was optimized and validated for analysis of three carbamates (aldicarb, carbofuran and carbaryl) in water samples. In this method, 2.0 mL of sample is placed in contact with 4.0 mL of acetonitrile. After agitation, the sample is placed in a freezer for 3 h for phase separation. The organic extract is analyzed by high performance liquid chromatography with ultraviolet detection (HPLC-UV). For validation of the technique, the following figures of merit were evaluated: accuracy, precision, detection and quantification limits, linearity, sensibility and selectivity. Extraction recovery percentages of the carbamates aldicarb, carbofuran and carbaryl were 90%, 95% and 96%, respectively. Even though extremely low volumes of sample and solvent were used, the extraction method was selective and the detection and quantification limits were between 5.0 and 10.0 microg L(-1), and 17.0 and 33.0 microg L(-1), respectively.


Assuntos
Carbamatos , Cromatografia Líquida de Alta Pressão/métodos , Resíduos de Praguicidas , Poluentes Químicos da Água , Aldicarb/análise , Carbamatos/análise , Carbaril/análise , Carbofurano/análise , Fracionamento Químico/métodos , Limite de Detecção , Resíduos de Praguicidas/análise , Poluentes Químicos da Água/análise
15.
J Forensic Sci ; 55(3): 808-12, 2010 May.
Artigo em Inglês | MEDLINE | ID: mdl-20345797

RESUMO

Foods contaminated with a granulated material similar to Temik (a commercial pesticide formulation containing the carbamate insecticide aldicarb) are often involved in accidental ingestion, suicides, and homicides in Brazil. We developed a simple technique to detect aldicarb. This technique is based on the inhibition of a stable preparation of the enzyme acetylcholinesterase, and it is specially adapted for forensic purposes. It comprises an initial extraction step with the solvent methylene chloride followed by a colorimetric acetylcholinesterase assay. We propose that results of testing contaminated forensic samples be expressed in aldicarb equivalents because, even though all other carbamates are also potent enzyme inhibitors, aldicarb is the contaminant most frequently found in forensic samples. This method is rapid (several samples can be run in a period of 2 h) and low cost. This method also proved to be precise and accurate, detecting concentrations as low as 40 microg/kg of aldicarb in meat samples.


Assuntos
Aldicarb/análise , Inibidores da Colinesterase/análise , Contaminação de Alimentos , Produtos da Carne , Acetilcolinesterase , Aldicarb/toxicidade , Animais , Bovinos , Inibidores da Colinesterase/toxicidade , Ensaio de Imunoadsorção Enzimática/métodos , Toxicologia Forense/métodos , Homicídio , Humanos , Modelos Lineares , Manejo de Espécimes , Suicídio
16.
J Chromatogr A ; 1216(36): 6394-9, 2009 Sep 04.
Artigo em Inglês | MEDLINE | ID: mdl-19651412

RESUMO

Photocatalytic properties of fibers containing TiO2 nanoparticles were explored for use as a self-decontaminating material using degradation of the pesticide aldicarb as the model toxin. During the analysis of the aldicarb treated sample by liquid chromatography (LC) with diode array detector (DAD), an unidentified peak was found at relative retention time (RT) 3.9 min when compared to aldicarb and major metabolites, aldicarb sulfoxide, and aldicarb sulfone. An analytical method was developed to confirm and identify this degradation product. LC-APCI/MS techniques were used first to analyze molecular ions and major fragments comparing retention times and spectra with those of known standards. FTIR and LC-MS/MS techniques were used to confirm the identity of the degradation product as 2-propenal, 2-methyl-, O-[(methylamino)carbonyl]oxime.


Assuntos
Resinas Acrílicas/química , Aldicarb/análise , Nanoestruturas/química , Resíduos de Praguicidas/análise , Titânio/química , Aldicarb/análogos & derivados , Aldicarb/efeitos da radiação , Catálise , Cromatografia Líquida de Alta Pressão/métodos , Descontaminação/métodos , Microquímica/métodos , Estrutura Molecular , Nanocompostos/química , Oximas/química , Fotólise , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Espectrometria de Massas em Tandem/métodos , Raios Ultravioleta
17.
Biosens Bioelectron ; 24(10): 3061-6, 2009 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-19380222

RESUMO

Integrated microring resonators fabricated on silicon wafers were used as signal transducers to detect alterations in physical traits of attached live mammalian cells. Cell adhesion and growth events could be monitored by the shift in resonance frequency of the microring resonator. Toxic chemical-induced changes in cell motility were rapidly detected based on variations in the fluctuation of resonance frequency. Microring resonators modified with an endothelial cell line (MS1) adhered onto its surface were used to detect the presence of two toxic chemicals, viz. sodium pentachlorophenate and Aldicarb at concentrations above the military exposure guideline levels within a duration of 1 h.


Assuntos
Técnicas Biossensoriais/instrumentação , Proliferação de Células , Poluentes Químicos da Água/análise , Aldicarb/análise , Aldicarb/toxicidade , Técnicas Biossensoriais/métodos , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Células Imobilizadas , Humanos , Pentaclorofenol/análise , Pentaclorofenol/toxicidade , Poluentes Químicos da Água/toxicidade
18.
Environ Toxicol Chem ; 26(7): 1355-60, 2007 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-17665674

RESUMO

United States potable well monitoring in the Pacific Northwest, California, Texas, Mississippi delta, and the Southeast was conducted in 2005 to provide estimates of dietary exposure to aldicarb carbamate residues (aldicarb and its two carbamate metabolites) in potentially vulnerable potable wells. Samples were analyzed from 1,673 drinking water wells in nine major use areas that were within 300 m of fields treated at least once with aldicarb between 2002 and 2005. Analyses were performed with a high-performance liquid chromatography/tandem mass spectrometry analytical method with limits of quantitation of 0.021 microg/L for aldicarb and aldicarb sulfone and 0.027 microg/L for aldicarb sulfoxide. The method detection limits were 0.0070 microg/L for aldicarb and aldicarb sulfone and 0.0090 microg/L for aldicarb sulfoxide. Samples from 1,513 of the 1,673 wells contained no aldicarb carbamate residues. Only 10 wells had total aldicarb carbamate residues above 1 microg/L, the maximum being 2.9 microg/L. All residues were below the U.S. Environmental Protection Agency Health Advisory Limit (HAL) of 10 microg/L. Given the number of samples collected in this study, there is a 95% confidence level that the maximum concentration in this study exceeds the 99.8th percentile of concentrations of all potable wells located within 300 m of fields recently treated with aldicarb. Therefore, the data from this study show that the restrictions and management practices on the current product label continue to be effective in preventing residues in excess of the 10 microg/L HAL in potable wells in these use areas.


Assuntos
Aldicarb/análise , Monitoramento Ambiental/métodos , Inseticidas/análise , Poluentes Químicos da Água/análise , Estados Unidos
19.
J AOAC Int ; 89(1): 214-24, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16512251

RESUMO

A sensitive method using liquid chromatography with electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) was developed and validated to quantify and confirm 13 pesticides, including aldicarb sulfoxide, aldicarb sulfone, oxamyl, methomyl, formetanate, 3-hydroxycarbofuran, carbendazim, thiabendazole, aldicarb, propoxur, carbofuran, carbaryl, and methiocarb, in soy-based infant formula. Data acquisition under MS/MS was achieved by applying multiple reaction monitoring of 2 fragment ion transitions to provide a high degree of sensitivity and selectivity for both quantitation and confirmation. Different approaches to constructing calibration curves were compared and discussed to address issues of the extraction efficiency or recovery, and matrix effects. Matrix-matched standard calibration curves with the use of isoprocarb as an internal standard were finally used to achieve the best accuracy of the method. Under most circumstances, recoveries of 13 pesticides, spiked at 5.0, 25.0, and 45.0 microg/kg, were close to 100%. The method detection limits (signal-to-noise ratio > or =3:1; microg/kg) of 13 pesticides were 0.2 for thiabendazole and methiocarb, 0.6 for aldicarb, and 0.1 for the others.


Assuntos
Técnicas de Química Analítica/métodos , Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Contaminação de Alimentos , Fórmulas Infantis/metabolismo , Praguicidas/análise , Soja/metabolismo , Espectrometria de Massas por Ionização por Electrospray/métodos , Aldicarb/análogos & derivados , Aldicarb/análise , Benzimidazóis/análise , Calibragem , Carbamatos/análise , Carbaril/análise , Carbofurano/análogos & derivados , Carbofurano/análise , Técnicas de Química Analítica/instrumentação , Íons , Espectrometria de Massas , Metiocarb/análise , Metomil/análise , Propoxur/análise , Sensibilidade e Especificidade , Tiabendazol/análise
20.
Chemosphere ; 62(10): 1630-5, 2006 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-16111737

RESUMO

Surfactant enhanced desorption of aldicarb from spiked soil was investigated in this paper. Anionic (sodium dodecyl benzene sulphonate, SDBS), cationic (hexadecyl trimethyl ammonium bromide, HTAB) and nonionic (octyl polyethylene glycol phenyl ether, OP) surfactants were tested to determine their optimal desorption conditions including desorption time, mixing speed and surfactant concentrations. The results showed that the optimal operating conditions were obtained at 2 h, 150 rpm, and surfactants concentrations were 1000, 100, and 200 mg l(-1) for SDBS, OP, and HTAB, respectively. The paper also investigated the desorption efficiency of mixture of different kinds of surfactants for aldicarb-spiked soil, and found that anionic-nonionic surfactant mixtures gave the best desorption efficiency up to 77%, while anionic-cationic surfactant mixture gave a poor desorption efficiency similar to water, suggesting that mixture of anionic-nonionic surfactants were highly promising on remediation of aldicarb-contaminated soil.


Assuntos
Aldicarb/análise , Poluentes do Solo/análise , Tensoativos/química , Adsorção , Cinética
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