RESUMEN
Rapid degradation of carbofuran (CBF) pesticide is effectively achieved by submerged thermal plasma (STP) without and with the addition of persulfate (PS) at two different concentrations (10 and 20 ppm). Degradation efficiency was examined using high-performance liquid chromatography (HPLC), and mineralization percentage was determined by total organic carbon (TOC) analysis. Adding 10 ppm PS showed higher degradation and mineralization percentages of 99.5% and 65.2%, respectively, than mere plasma treatment and 20 ppm PS addition to CBF solution. A relatively higher energy yield of 40 mg/kWh and a first order kinetic reaction rate of 0.262 min-1 were obtained in the 10 PS added STP treatment. Liquid chromatography mass spectrometry (LCMS) analysis illustrated reaction intermediates formed during plasma treatment. Scavenger investigation implied that â¢OH radical is the prime cause of CBF degradation, as degradation percentage declined to 50% in all conditions. Toxicity assessment of CBF and its degradation products was predicted using Toxicity estimation software tool (TEST), and plasma treated solutions (PTS) were experimentally investigated on Eudrilus eugeniae earthworms by monitoring its mortality rate, self-assemblage, and histopathological analysis. A lower mortality rate (46%) and self-assemblage (167 s) of earthworms were detected for plasma treated CBF than for the other conditions. The results reveal that PTS is less toxic for earthworms than untreated CBF solution. These findings imply that STP is an effective technique for bio-recalcitrant pollutants degradation in agrochemical industries.
Asunto(s)
Carbofurano , Contaminantes Ambientales , Plaguicidas , Gases em Plasma , Contaminantes Químicos del Agua , Carbofurano/química , Plaguicidas/análisis , Gases em Plasma/análisis , Contaminantes Ambientales/análisis , Cinética , Contaminantes Químicos del Agua/análisis , Oxidación-ReducciónRESUMEN
Carbofuran is a pesticide widely used in agricultural context to kill insects, mites, and flies by ingestion or contact. Along with literature review, we aimed to (i) present the clinical, autopsy, and toxicological findings of carbofuran self-poisonings in two 69-year-old twins, resulting in the death of one of them and (ii) assess carbofuran metabolite distribution using molecular networking. Quantitative analysis of carbofuran and its main metabolites (3-hydroxycarbofuran and 3-ketocarbofuran) was carried out using an original liquid chromatography-tandem mass spectrometry method on biological samples (cardiac or peripheral blood, urine, bile, and gastric contents). Toxicological analysis of post-mortem samples (twin 1) highlighted high concentrations of carbofuran and its metabolites in cardiac blood, bile, and gastric contents. These compounds were also quantified in blood and/or urine samples of the living brother (twin 2), confirming poisoning. Using molecular networking approach to facilitate visualization of mass spectrometry datasets and sample-to-sample comparisons, we detected two more metabolites (7-phenol-carbofuran and 3-hydroxycarbofuran glucuronide) in bile (twin 1) and urine (twin 2). These results highlight the value of (i) these compounds as carbofuran consumption markers and (ii) bile samples in post-mortem analysis to confirm poisoning. From an analytical point of view, molecular networking allowed the detection and interpretation of carbofuran metabolite ammonium adducts which helped to confirm their identification annotations, as well as their structural data. From a clinical point of view, the different outcomes between the two brothers are discussed. Overall, these cases provide novel information regarding the distribution of carbofuran and its metabolites in poisoning context.
Asunto(s)
Compuestos de Amonio , Carbofurano , Insecticidas , Plaguicidas , Animales , Carbofurano/análogos & derivados , Carbofurano/análisis , Carbofurano/química , Carbofurano/metabolismo , Glucurónidos , Insecticidas/análisis , Masculino , FenolesRESUMEN
The transformation of carbosulfan (CSN) in apples was investigated during oven-drying, microwave drying, and sun-drying. CSN transformed primarily into carbofuran (COA) during these drying processes. The conversion kinetics of CSN and COA was fitted by curve regression and mainly conformed to quadratic models (R2 = 0.70-0.97). Oven-drying promoted the transformation of CSN into COA. Microwave drying resulted in the highest scavenging capacity against CSN and COA (41%-100%). Moreover, a transformation mechanism was proposed on the basis of density functional theory (DFT) calculation. The COA originated from a series of chemical reactions involving hydroxyl substitution, cleavage, and oxidation; this result was further confirmed on the basis of molecular electrostatic potential (MEP) and molecular orbital theory. Furthermore, the toxicity and stability of CSN and COA were evaluated with the T.E.S.T. program. COA was less toxic than CSN to aquatic organisms but more toxic than CSN to rats. Therefore, COA production should be avoided during drying. Microwave drying was found to be the optimum choice for drying apples.
Asunto(s)
Carbamatos/metabolismo , Desecación/métodos , Manipulación de Alimentos/métodos , Malus/química , Animales , Organismos Acuáticos/efectos de los fármacos , Carbamatos/química , Carbamatos/toxicidad , Carbofurano/química , Carbofurano/metabolismo , Carbofurano/toxicidad , Desecación/instrumentación , Manipulación de Alimentos/instrumentación , Depuradores de Radicales Libres/análisis , RatasRESUMEN
In the present study, two agro-industrial wastes, sugarcane bagasse, and peanut shell were employed as support of magnetite nanoparticles for the synthesis of magnetic bio-composites: magnetic sugarcane bagasse (MBO) and magnetic peanut shell (MPSo). The presence of magnetite was verified by Raman spectroscopy. Magnetic nanoparticles shape and size distribution were studied by TEM, while composites morphologies were observed by SEM. Structural characteristics of the pesticides and their possible chemical adsorption on composites were analyzed by FTIR. The removal was carried out by a batch adsorption process, and UV-VIS technique was used for pesticide concentration estimation. Elovich model described better all systems pointing out to a chemical adsorption process occurring. Experimental data isotherms of carbofuran and iprodione can be best explained by more than one mathematical model, but Sip was the ordinary equation in all systems. Maximum adsorption capacities of 175 and 89.3 mg/g for carbofuran, and 119 and 2.76 mg/g for iprodione, were obtained for MBo and MPSo, respectively.
Asunto(s)
Aminoimidazol Carboxamida/análogos & derivados , Arachis/química , Carbofurano , Hidantoínas/química , Plaguicidas , Saccharum , Contaminantes Químicos del Agua , Adsorción , Aminoimidazol Carboxamida/química , Carbofurano/química , Celulosa , Fenómenos MagnéticosRESUMEN
In this study, porous sandwich structure Fe3 O4 nanoparticles coated by polyhedral oligomeric silsesquioxanes and ß-cyclodextrin were prepared by surface polymerization and were used as the magnetic solid phase extraction adsorbent for the extraction and determination of carbaryl and carbofuran. The Fe3 O4 nanoparticles coated with polyhedral oligomeric silsesquioxanes and ß-cyclodextrin were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, thermogravimetric analysis, vibrating sample magnetometry, and scanning electron microscopy. After optimizing the extraction conditions, a method that combined magnetic solid phase extraction with high-performance liquid chromatography was developed for the determination of carbaryl and carbofuran in apple. The method exhibited a good linearity in the range of 2-400 µg/kg for carbaryl and carbofuran (R2 = 0.9995), respectively. The limits of detection were 0.5 µg/kg of carbaryl and 0.7 µg/kg for carbofuran in apple, respectively. Extraction recoveries ranged from 94.2 to 103.1% with the preconcentration factor of 300 and the relative standard deviations were less than 5.9%. These results indicated that the method combined magnetic solid phase extraction with high-performance liquid chromatography and was promising for the determination of carbaryl and carbofuran at trace amounts.
Asunto(s)
Carbaril/aislamiento & purificación , Carbofurano/aislamiento & purificación , Nanopartículas de Magnetita/química , Siloxanos/química , Extracción en Fase Sólida , beta-Ciclodextrinas/química , Carbaril/química , Carbofurano/química , Fenómenos MagnéticosRESUMEN
A hybrid process was proposed for carbofuran (CBF) degradation, a carbamate pesticide with a special refractory property, through peroxymonosulfate (PMS) activation under visible LED (Vis LED) by FeIII impregnated N-doped TiO2 photocatalyst (FeNT). An in-depth investigation was conducted to examine the synergistic effect of the FeNT/PMS/Vis LED process under various reaction conditions. An increase in the rate constant was observed with the increment of pH from 2.4 to 7.4, implying the feasibility of the process at neutral pH. A further increase in pH from 8.9 to 11 showed a sudden drop in the rate constant (if the role of base activation is ignored). The efficiency of CBF degradation is still more than 70% after adding NO3-, SO42-, HCO3-, and Cl-. Interestingly, the efficiency was not influenced even after the further increment of nitrate concentration. Furthermore, the high chloride concentrations caused an enhanced efficiency due to the generation of reactive halogens through two-electron transfer. Sixteen major intermediates were recognized and eight of them were never reported in the previous studies. Surprisingly, a new degradation pathway was noted in this study via H-abstractions and cyclization mechanisms. The FeNT/PMS/Vis LED process exhibited a dual functionality in terms of mineralization efficiency and about 90% TOC reduction can be achieved. Therefore, these findings provide new insights into the mechanism of PMS activation under Vis LED after coupling non-metal doped TiO2 photocatalyst with a metal component, and its implications for degradation of refractory and non-biodegradable pollutants in wastewater.
Asunto(s)
Carbofurano/química , Peróxidos/química , Contaminantes Químicos del Agua/química , Compuestos Férricos , Aguas Residuales , Contaminantes Químicos del Agua/análisisRESUMEN
The characterization of soluble cholinesterases (ChEs) together with carboxylesterases (CEs) in Ficopomatus enigmaticus as suitable biomarkers of neurotoxicity was the main aim of this study. ChEs of F. enigmaticus were characterized considering enzymatic activity, substrate affinity (acetyl-, butyryl-, propionylthiocholine), kinetic parameters (Km and Vmax) and in vitro response to model inhibitors (eserine hemisulfate, iso-OMPA, BW284C51), and carbamates (carbofuran, methomyl, aldicarb, and carbaryl). CEs were characterized based on enzymatic activity, kinetic parameters and in vitro response to carbamates (carbofuran, methomyl, aldicarb, and carbaryl). Results showed that cholinesterases from F. enigmaticus showed a substrate preference for acetylthiocholine followed by propionylthiocholine; butyrylthioline was not hydrolyzed differently from other Annelida species. CE activity was in the same range of cholinesterase activity with acetylthiocholine as substrate; the enzyme activity showed high affinity for the substrate p-nytrophenyl butyrate. Carbamates inhibited ChE activity with propionylthiocholine as substrate to a higher extent than with acetylthiocoline. Also CE activity was inhibited by all tested carbamates except carbaryl. In vitro data highlighted the presence of active forms of ChEs and CEs in F. enigmaticus that could potentially be inhibited by pesticides at environmentally relevant concentration.
Asunto(s)
Anélidos/enzimología , Inhibidores de la Colinesterasa/toxicidad , Colinesterasas/química , Neurotoxinas/toxicidad , Animales , Anélidos/efectos de los fármacos , Biomarcadores/química , Carbamatos/química , Carbaril/química , Carbaril/toxicidad , Carbofurano/química , Carbofurano/toxicidad , Hidrolasas de Éster Carboxílico/antagonistas & inhibidores , Hidrolasas de Éster Carboxílico/química , Hidrolasas de Éster Carboxílico/metabolismo , Inhibidores de la Colinesterasa/química , Colinesterasas/metabolismo , Cinética , Metomil/química , Metomil/toxicidad , Neurotoxinas/químicaRESUMEN
The residues of deltamethrin (DM) and carbofuran (CBF) in soil is becoming an intractable problem causing soil hardening and environmental pollution. This paper reports a very simple method via improved reduction of chloroauric acid by the trisodium citrate method for fabricating gold nanoparticles (AuNPs), which were used as a surface enhanced Raman scattering (SERS) active colloids with the advantages of ultrasensitivity, reproducibility and chemical stability. The results demonstrated that the limits of detection (LODs) of the DM and CBF were found to be as low as 0.01 mg/L. The SERS intensity showed a good linear relationship with DM (R² = 0.9908) and CBF (R² = 0.9801) concentration from 0.01 to 10 mg/L. In a practical application, DM and CBF residues in soil were easily detected by SERS with the flexible AuNPs colloids, and the LODs of DM and CBF were found to be as low as 0.056 mg/kg and 0.053 mg/kg, respectively. Moreover, DM in soil could be qualitatively detected by the characteristic peaks at 560 and 1000 cm-1, and CBF in soil could be qualitatively detected by the characteristic peaks at 1000 and 1299 cm-1. The determination coefficient (R²p) for DM and CBF reached 0.9176 and 0.8517 in partial least squares (PLS) model. Overall, it is believed that the prepared AuNPs can provide technical support for the accurate detection of pesticide residues in soil by SERS technique.
Asunto(s)
Carbofurano/análisis , Oro/química , Nanopartículas del Metal/química , Nitrilos/análisis , Piretrinas/análisis , Suelo/química , Espectrometría Raman/métodos , Carbofurano/química , Límite de Detección , Nitrilos/química , Residuos de Plaguicidas/análisis , Residuos de Plaguicidas/química , Piretrinas/química , Reproducibilidad de los ResultadosRESUMEN
BACKGROUND: High levels of harmful pesticide residues in rice can cause undesirable side effects and are a source of great concern to consumers. Reduction of pesticide residues to provide rice security has thus became an urgent problem. RESULTS: In this study, the effects of commercial and home processing on removal of chlorpyrifos and carbosulfan residues from rice, and the formation of metabolites during processing, were studied. The results showed that 3,5,6-trichloro-2-pyridinol (0.87 mg kg-1 ) and carbofuran (0.43 mg kg-1 ) were the predominant components detected in paddy rice. All detected residues were primarily deposited on the rice hull and bran. Washing twice followed by high-pressure cooking was able to further decrease residues in polished rice with the processing factor value <0.25. Following application of pesticides at the recommended rate and twice the recommended rate, with a preharvest interval of 28 days, changes in residues from harvest to dining table based on efficient processing techniques were investigated. The final residues dropped to below maximum residue levels after washing twice followed by high-pressure cooking. CONCLUSION: This simple cooking process thus reduces the risk of dietary exposure, and it is recommended that it is adopted by all consumers. © 2019 Society of Chemical Industry.
Asunto(s)
Culinaria/métodos , Oryza/química , Residuos de Plaguicidas/química , Carbamatos/química , Carbofurano/química , Cloropirifos/química , Contaminación de Alimentos/análisis , CinéticaRESUMEN
Exposing second-stage juveniles (J2) of Meloidogyne incognita in vitro to a phenolic compound sometimes fails to cause J2 mortality, but in tests in vivo the same compound may reduce the infectivity and population of the nematode. This work aimed to study the effect of phenolic compounds on M. incognita through in vitro and in vivo assays. In the in vitro assay 49 phenolic compounds were screened for their toxicity to M. incognita J2. As a result, D-(-)-4-hydroxyphenylglycine, t-butylhydroquinone, L-3-(3,4-dihydroxyphenyl)alanine, sesamol, 2,4-dihydroxyacetophenone, and p-anisaldehyde increased the J2 mortality. These compounds presented, respectively, the following lethal concentrations to 50% of J2 (LC50): 365, 352, 251, 218, 210, and 85⯵g/mL, while Carbofuran (positive control) had 150⯵g/mL. However, none of these compounds were efficient in controlling the nematode in inoculated tomato plants, even when 2.77-fold of their LC50 were used. Although inactive in the in vitro test at 500⯵g/mL, hydroquinone (3.5â¯mg per plant) reduced M. incognita population and galls by up to 99% to levels similar to the nematicide Carbofuran (1.2â¯mg per plant). Additionally, hydroquinone increased the root weight when compared to the negative and positive controls, water/NaOH and Carbofuran, respectively. In this study, we showed that some phenolic compounds, hydroquinone in particular, revealed a potential new option for the control of M. incognita.
Asunto(s)
Fenoles/farmacología , Solanum lycopersicum/parasitología , Tylenchoidea/efectos de los fármacos , Animales , Arbutina/administración & dosificación , Arbutina/química , Arbutina/farmacología , Benzaldehídos/administración & dosificación , Benzaldehídos/química , Benzaldehídos/farmacología , Ácidos Cafeicos/administración & dosificación , Ácidos Cafeicos/química , Ácidos Cafeicos/farmacología , Carbofurano/administración & dosificación , Carbofurano/química , Carbofurano/farmacología , Catecoles/administración & dosificación , Catecoles/química , Catecoles/farmacología , Glicerol/administración & dosificación , Glicerol/química , Glicerol/farmacología , Hidroquinonas/administración & dosificación , Hidroquinonas/química , Hidroquinonas/farmacología , Hidroxibenzoatos/administración & dosificación , Hidroxibenzoatos/química , Hidroxibenzoatos/farmacología , Dosificación Letal Mediana , Naftoles/administración & dosificación , Naftoles/química , Naftoles/farmacología , Fenoles/administración & dosificación , Fenoles/química , Distribución Aleatoria , Resorcinoles/administración & dosificación , Resorcinoles/química , Resorcinoles/farmacología , Factores de TiempoRESUMEN
We report on the rates of decomposition of a group of N-methylcarbamate (NMC) pesticides (carbaryl, carbofuran and propoxur) under pre-determined tropical field conditions. Rates of decomposition for three NMCs were determined at pH 7.08 and T = 20 °C and pH 7.70 and T = 33 °C respectively, as follows: carbaryl (78 days and 69 days); carbofuran (143 days and 83 days) and propoxur (116 days and 79 days). Investigation on methods for removal of NMCs and their phenolic decomposition products shows that activated charcoal outperforms zeolite, alumina, diatomaceous earth, cellulose and montmorillonite clay in the removal of both NMCs and phenols from aqueous solution. Furthermore, metal complexation studies on the NMCs and phenols showed that Fe (III) forms a complex with isopropoxyphenol (IPP) within which the Fe:IPP ratio is 1:3, indicative of the formation of a metal chelate complex with the formula Fe(IPP)3.
Asunto(s)
Carbamatos/química , Metales/química , Plaguicidas/química , Plaguicidas/aislamiento & purificación , Bentonita/química , Biodegradación Ambiental , Carbaril/química , Carbaril/aislamiento & purificación , Carbofurano/química , Carbofurano/aislamiento & purificación , Celulosa/química , Arcilla/química , Hidrólisis , Fenoles/química , Propoxur/química , Propoxur/aislamiento & purificación , Soluciones/química , Clima Tropical , Contaminantes Químicos del Agua/química , Contaminantes Químicos del Agua/aislamiento & purificación , Zeolitas/químicaRESUMEN
Carbofuran is an anticholinesterase carbamate commonly used as an insecticide, nematicide and acaricide in agricultural practice throughout the world. However, data on its sorption in temperate soils from Europe is limited. Laboratory studies were conducted to determine the adsorption of carbofuran on three distinct Austrian soils using batch experiments and radiometric techniques. Carbofuran adsorption capacity of the soils was found to be low in the three soils tested and showed to be related to the soils clay and organic carbon contents. The pesticide presented linear adsorption isotherms in all of the three soils. Due to the low sorption of carbofuran in the soils tested and to its high water solubility, there is a risk of migration to water bodies through run off and consequent negative effects on aquatic organisms and soil biota.
Asunto(s)
Carbofurano/química , Modelos Químicos , Contaminantes del Suelo/química , Adsorción , Agricultura , Austria , Carbamatos , Carbofurano/análisis , Radioisótopos de Carbono/análisis , Inhibidores de la Colinesterasa , Arcilla , Insecticidas/análisis , Plaguicidas , Suelo/química , Contaminantes del Suelo/análisisRESUMEN
In order to contribute to the increase of the body of knowledge on the sensitivity of tropical indigenous species to pesticides, acute and chronic toxicity tests were conducted with the neotropical cladoceran Ceriodaphnia silvestrii. Tests were carried out with the active ingredients diuron and carbofuran and one of their commercial formulations, the Diuron Nortox® 500 SC and the Furadan® 350 SC, respectively. For carbofuran, the active ingredient was more toxic than the commercial product, whereas for diuron, the commercial product appeared more toxic. In addition, hormetic effects on fertility were recorded for intermediate diuron concentrations. Acute and chronic toxicity data indicated that C. silvestrii was among the most sensitive invertebrate species for both test compounds. Based on concentrations measured in Brazilian water bodies, these compounds represent ecological risks for causing direct and indirect toxic effects on C. silvestrii and other aquatic organisms. Our results support previous claims on the advantages of using native species to better tune ecological risk assessment of chemicals in tropical ecosystems.
Asunto(s)
Carbofurano/química , Cladóceros/efectos de los fármacos , Diurona/química , Plaguicidas/química , Animales , Brasil , Cladóceros/química , Ecología , Ecosistema , Plaguicidas/farmacologíaRESUMEN
Water quality assessment was conducted on the Ruiru River, a tributary of an important tropical river system in Kenya, to determine baseline river conditions for studies on the aquatic fate of N-methyl carbamate (NMC) pesticides. Measurements were taken at the end of the long rainy season in early June 2013. Concentrations of copper (0.21-1.51 ppm), nitrates (2.28-4.89 ppm) and phosphates (0.01-0.50 ppm) were detected at higher values than in uncontaminated waters, and attributed to surface runoff from agricultural activity in the surrounding area. Concentrations of dissolved oxygen (8-10 ppm), ammonia (0.02-0.22 ppm) and phenols (0.19-0.83 ppm) were found to lie within normal ranges. The Ruiru River was found to be slightly basic (pH 7.08-7.70) with a temperature of 17.8-21.2°C. The half-life values for hydrolysis of three NMC pesticides (carbofuran, carbaryl and propoxur) used in the area were measured under laboratory conditions, revealing that rates of decay were influenced by the electronic nature of the NMCs. The hydrolysis half-lives at pH 9 and 18°C decreased in the order carbofuran (57.8 h) > propoxur (38.5 h) > carbaryl (19.3 h). In general, a decrease in the electron density of the NMC aromatic ring increases the acidity of the N-bound proton removed in the rate-limiting step of the hydrolysis mechanism. Our results are consistent with this prediction, and the most electron-poor NMC (carbaryl) hydrolyzed fastest, while the most electron-rich NMC (carbofuran) hydrolyzed slowest. Results from this study should provide baseline data for future studies on NMC pesticide chemical fate in the Ruiru River and similar tropical water systems.
Asunto(s)
Carbamatos/análisis , Plaguicidas/análisis , Contaminantes Químicos del Agua/análisis , Calidad del Agua , Carbamatos/química , Carbaril/análisis , Carbaril/química , Carbofurano/análisis , Carbofurano/química , Semivida , Hidrólisis , Kenia , Propoxur/análisis , Propoxur/química , Lluvia , Ríos/química , Estaciones del Año , Relación Estructura-Actividad , Clima TropicalRESUMEN
Antibiotic-containing wastewaters produced in agricultural activities may depress the pesticide-degrading capacity of biomixtures contained in biopurification systems. This work aimed to assay the effect of oxytetracycline (OTC) on the removal of carbofuran (CFN) in an optimized biomixture, and to determine the capacity of the system to dissipate OTC. During co-application of CFN+OTC, CFN removal and its accelerated degradation were not negatively affected. Similarly, different doses of OTC (10-500mgkg-1) did not significantly affect CFN mineralization, and the process even exhibited a hormetic-like effect. Moreover, the biomixture was able to remove OTC with a half-life of 34.0 d. DGGE-cluster analyses indicated that fungal and bacterial communities remained relatively stable during OTC application and CFN+OTC co-application, with similarities of over 70% (bacteria) and 80% (fungi). Overall, these findings support the potential use of this matrix to discard OTC-containing wastewater in this system originally intended for CFN removal.
Asunto(s)
Carbofurano/química , Oxitetraciclina/química , Plaguicidas/análisis , Aguas Residuales/análisis , Biodegradación Ambiental , Carbofurano/metabolismo , Granjas , Oxitetraciclina/metabolismoRESUMEN
Agricultural pesticides used with the criminal intent to intoxicate domestic and wild animals are a serious concern in Veterinary Medicine. In order to identify the pesticide carbofuran and its metabolite 3- hydroxycarbofuran in animals suspected of exogenous intoxication a high pressure liquid chromatography with diode array detector (HPLC-DAD) method was developed and validated in stomach contents, liver, vitreous humor and blood. The method was evaluated using biological samples from seven different animal species. The following parameters of analytical validation were evaluated: linearity, precision, accuracy, selectivity, recovery and matrix effect. The method was linear at the range of 6.25-100µg/mL and the correlation coefficient (r2) values were >0.9811 for all matrices. The precision and accuracy of the method was determined by coefficient of variation (CV) and the relative standard deviation error (RSE), and both were less than 15%. Recovery ranged from 74.29 to 100.1% for carbofuran and from 64.72 to 100.61% for 3-hydroxycarbofuran. There were no significant interfering peaks or matrix effects. This method was suitable for detecting 25 positive cases for carbofuran amongst a total of 64 animal samples suspected of poisoning brought to the Toxicology Diagnostic Laboratory, School of Veterinary Medicine and Animal Sciences, University of Sao Paulo.
Asunto(s)
Carbofurano/análogos & derivados , Carbofurano/análisis , Cromatografía Líquida de Alta Presión/métodos , Medicina Legal/métodos , Intoxicación/diagnóstico , Intoxicación/veterinaria , Medicina Veterinaria/métodos , Animales , Carbofurano/sangre , Carbofurano/química , Gatos , Perros , Contenido Digestivo/química , Límite de Detección , Modelos Lineales , Hígado/química , Reproducibilidad de los Resultados , Cuerpo Vítreo/químicaRESUMEN
Carbofuran is a toxic carbamate pesticide, and its use has increased in recent years. While marketing information indicates stability in different chemical media, carbofuran exhibits relative photolability. The aim of this research was to decompose carbofuran and to identify the photoproducts achieved when two different doped titania photocatalysts were employed under UV irradiation. The iron-doped TiO2 materials were obtained (a) via a hydrothermal method and (b) by an ultrasound-assisted sol-gel method. The precursors were TiOSO4â xH2O and Fe3(NO3)·9H2O. X-ray studies confirmed that the anatase phase of the iron-doped TiO2 resulted from the two preparation methods. The photocatalytic performance of the prepared materials was monitored by LC/ESI-QTOF-MS, enabling the identification of photoproducts: oxo-carbamates, hydroxylated benzofuranes, a carboxamide, and one amine. By using the iron-doped TiO2 materials, 2,2-dimethyl-2,3-dihydrobenzofuran-3,7-diol was the most abundant photoproduct, and N,2,2-trimethyl-2,3-dihydrobenzofuran-7-amine was the only compound that had not been previously reported in the photolysis and photocatalysis of carbofuran. The product 3-hydroxy carbofuran, a cholinesterase inhibitor, was quantified and was found to be transformed into compounds that lack this inhibitive property.
Asunto(s)
Carbofurano/química , Hierro/química , Titanio/química , Carbofurano/análogos & derivados , Catálisis , Colinesterasas , Fotólisis , Rayos UltravioletaRESUMEN
A comparative study on photocatalytic degradation of the pesticide carbofuran and its commercial product Furadan 35-ST in an aqueous suspension of ZnO, irradiated by long-wave light (315-400 nm), is presented in this study. In order to assess the effects of inert ingredients present in the commercial product Furadan 35-ST, non-competitive and competitive adsorption and kinetic studies of carbofuran degradation processes were conducted. A higher photochemical degradation rate was found for pure carbofuran in comparison to a two-component system, carbofuran and single addition of ingredients at appropriate concentrations, and the commercial product Furadan 35-ST. The overall effect of inert ingredients was evaluated from a competitive study using the model system of Furadan 35-ST. The results of a mineralization study, obtained by ion chromatography (IC) and total organic carbon (TOC) analyses, revealed the formation of acetate, oxalate, and formate ions. Photodegradation products of carbofuran, three of them detected for the first time, were identified based on high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and gas chromatography-mass spectrometry (GC-MS) results, and their photodegradation pathways were proposed.
Asunto(s)
Carbofurano/química , Espectrometría de Masas en Tándem , Cromatografía de Gases y Espectrometría de Masas , Insecticidas , Cinética , FotólisisRESUMEN
Carbofuran (CBF) removal in a continuous-flow photocatalytic reactor with granular activated carbon supported titanium dioxide (GAC-TiO2) catalyst was investigated. The effects of feed flow rate, TiO2 concentration and addition of supplementary oxidants on CBF removal were investigated. The central composite design (CCD) was used to design the experiments and to estimate the effects of feed flow rate and TiO2 concentration on CBF removal. The outcome of CCD experiments demonstrated that reactor performance was influenced mainly by feed flow rate compared to TiO2 concentration. A second-order polynomial model developed based on CCD experiments fitted the experimental data with good correlation (R2 â¼ 0.964). The addition of 1 mL min-1 hydrogen peroxide has shown complete CBF degradation and 76% chemical oxygen demand removal under the following operating conditions of CBF â¼50 mg L-1, TiO2 â¼5 mg L-1 and feed flow rate â¼82.5 mL min-1. Rate constant of the photodegradation process was also calculated by applying the kinetic data in pseudo-first-order kinetics. Four major degradation intermediates of CBF were identified using GC-MS analysis. As a whole, the reactor system and GAC-TiO2 catalyst used could be constructive in cost-effective CBF removal with no impact to receiving environment through getaway of photocatalyst.
Asunto(s)
Carbofurano/aislamiento & purificación , Contaminantes Ambientales/aislamiento & purificación , Análisis de la Demanda Biológica de Oxígeno , Carbofurano/química , Carbofurano/metabolismo , Catálisis , Carbón Orgánico , Contaminantes Ambientales/química , Contaminantes Ambientales/metabolismo , Diseño de Equipo , Cromatografía de Gases y Espectrometría de Masas , Peróxido de Hidrógeno/química , Cinética , Fotobiorreactores , Fotólisis , Titanio/química , Rayos UltravioletaRESUMEN
In this research, a sensitive and selective method for detecting one of the most toxic insecticides, "carbofuran", in rice and soybean is presented. This method is based on the coupling reaction of diazonium ion combined with a surface-enhanced Raman scattering technique. Diazonium ion produced from p-aminothiophenol reacts specifically with carbofuran phenol from the hydrolysis of carbofuran. The generated azo compounds attach to the surface of silver nanoparticles via the Ag-S bond. Therefore, a strong Raman intensity can be obtained. The concentration of carbofuran can be determined by following the intensity of the peak at 1201 cm-1, attributed to the C-N stretching vibration of the azo compound. The result shows a good linear correlation (R2 = 0.9786) against carbofuran concentrations (0.1 - 5 ppm) with a detection limit of 0.452 ppm. Our proposed protocol is insignificantly influenced by various common interferences. Moreover, this method has been successfully validated to determine carbofuran concentrations in rice and soybean with detection limits of 0.446 and 0.520 ppm, respectively.