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This research presents a novel method for measuring ethanol concentrations using a smartphone. The method involves an oxidation reaction with potassium dichromate and concentrated sulfuric acid, resulting in a green-blue color formation. The color intensity, corresponding to ethanol concentrations ranging from 0 to 100%, was captured using a smartphone camera within a specialized photography box. The images were then analyzed using a specific application, converting the color signal into an absorbance value. The calibration curve demonstrated excellent linearity in the range of 0-0.55 v/v % and its detection limit is 0.01 v/v%, with a correlation coefficient exceeding 0.995. The method was successfully applied to measure ethanol in real samples, including ordinary rose water and a bitter wheat drink.â¢The method is inexpensive.â¢The method is rapid.â¢The method is green.
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Background: Curcumin is an extract of rhizome turmeric (diferuloylmethane), with antioxidant, anti-inflammatory, antimicrobial, and anti-parasitic properties, which making it a potential candidate for the treatment of leishmaniasis. The aim of the presented study was to evaluate curcumin as possible candidate for treatment of cutaneous leishmaniasis. Methods: We investigated the physicochemical properties and anti-leishmanial effects of nanoliposomal curcumin (40, 80, and 120 µM) in Leishmania major (MRHO/IR/75/ER) infected BALB/c mice at the faculty of Veterinary Medicinem University of Tehran, Iran. For this aim, L. major promastigotes (MHROM/IR/75/ER) at stationary phase (2×106) were inoculated sub-cutaneously into the upper area of the tail in BALB/c mice (six groups, n= 10 per group). For evaluation of nanoliposomal curcumin, the zeta potential, particle size and stability of nanoliposomal curcumin was determined. Furthermore, the anti-leishmanial effects of nanoliposomal curcumin formulation on the lesion sizes was determined and the parasite burden in the leishmania induced lesion was performed using semi quantitative PCR. Results: Treatment of L. major infected BALB/c mice with nanoliposomal curcumin led to a reduction in the kinetic of the skin lesion size development. The semi quantitative PCR analysis of DNA extracted from the lesions showed reduction of parasite burden. The most effective treatment could be found in 80 µM nanoliposomal curcumin. Treatment with Glucantime, as a positive control, also showed a nearly similar effect compared to the effect of 80 µM nanoliposomal curcumin. Conclusion: Nanoliposomal curcumin could be considered as a potential drug against cutaneous leishmaniasis caused by L. major in susceptible animal models.
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In this study, a smartphone was used as the photometer for determination of iron (III) by forming a complex with thiocyanate. After color formation at concentrations of, image capture with mobile phone, signal analysis of each sample was performed by the application and converted to the absorption number. The calibration curve was completely linear in the range of 10 to 80 mg L-1 used and the linear coefficient was better than 0.9833. The limits of detection (LOD) and quantification (LOQ) were 0.1 and 0.3 mg L-1, respectively. Finally, this method was successfully used to measure iron in real samples.â¢A smartphone was used for the determination of iron (III), showcasing its potential in color compound analysis.â¢The method demonstrated superior performance in terms of calibration curve range and measurement speed compared to traditional atomic absorption devices.â¢The technique was successfully applied in the measurement of iron in real samples, indicating its practical applicability.
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BACKGROUND: Side effects associated with antimicrobial drugs, as well as their high cost, have prompted a search for low-cost herbal medicinal substances with fewer side effects. These substances can be used as supplements to medicine or to strengthen their effects. The current study investigated the effect of oleuropein on the inhibition of fungal and bacterial biofilm in-vitro and at the molecular level. MATERIALS AND METHODS: In this experimental study, antimicrobial properties were evaluated using microbroth dilution method. The effect of oleuropein on the formation and eradication of biofilm was assessed on 96-well flat bottom microtiter plates and their effects were observed through scanning electron microscopy (SEM). Its effect on key genes (Hwp1, Als3, Epa1, Epa6, LuxS, Pfs) involved in biofilm formation was investigated using the quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) method. RESULTS: The minimum inhibitory concentration (MIC) and minimum fungicidal/bactericidal concentration (MFC/MBC) for oleuropein were found to be 65 mg/ml and 130 mg/ml, respectively. Oleuropein significantly inhibited biofilm formation at MIC/2 (32.5 mg/ml), MIC/4 (16.25 mg/ml), MIC/8 (8.125 mg/ml) and MIC/16 (4.062 mg/ml) (p < 0.0001). The anti-biofilm effect of oleuropein was confirmed by SEM. RT-qPCR indicated significant down regulation of expression genes involved in biofilm formation in Candida albicans (Hwp1, Als3) and Candida glabrata (Epa1, Epa6) as well as Escherichia coli (LuxS, Pfs) genes after culture with a MIC/2 of oleuropein (p < 0.0001). CONCLUSIONS: The results indicate that oleuropein has antifungal and antibacterial properties that enable it to inhibit or destroy the formation of fungal and bacterial biofilm.
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Antifúngicos , Biopelículas , Candida albicans , Candida glabrata , Escherichia coli , Fluconazol , Glucósidos Iridoides , Iridoides , Pruebas de Sensibilidad Microbiana , Biopelículas/efectos de los fármacos , Biopelículas/crecimiento & desarrollo , Glucósidos Iridoides/farmacología , Candida glabrata/efectos de los fármacos , Candida glabrata/fisiología , Candida glabrata/genética , Candida albicans/efectos de los fármacos , Candida albicans/genética , Candida albicans/fisiología , Escherichia coli/efectos de los fármacos , Escherichia coli/genética , Iridoides/farmacología , Fluconazol/farmacología , Antifúngicos/farmacología , Farmacorresistencia Fúngica , Antibacterianos/farmacología , Microscopía Electrónica de RastreoRESUMEN
In this study, effect of some solvents (ethanol, acetonitrile and water) for the extraction of phenolic compounds was investigated. Solvent volume, temperature and duration of the extraction process have a positive correlation with the amounts of phenolic compounds and antioxidant activity. The amounts of phenolic compounds, especially oleuropein in the leaf extract is higher than the fruit extract, and the concentration of oleuropein content in leaves and fruits extract was 4900 and 1800 mg/L, respectively. The oleuropein extracted from olive leaves was purified with liquid-liquid extraction to above 98%, and its concentration in leaves was 9.8 w/w/% in dried leaves.
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This paper introduces a novel, sensitive, and rapid method for the quantification of oxytetracycline, tetracycline, tilmicosin, and tylosin residues in cow's milk. The method involves a two-step process of extraction and detection. The extraction process uses acetonitrile and salting-out assisted liquid-liquid extraction to isolate the antibiotics from the milk. The detection process employs Liquid Chromatography coupled with photo-diode array detector (PDA) to quantify the antibiotics. The method has been successfully applied to milk samples, demonstrating its effectiveness and potential for widespread use in residue analysis.â¢The calibration curves for the antibiotics were found to be linear within the range of 0.06-3.0 µg/mL to 0.1-3.0 µg/mL.â¢The limits of detection for oxytetracycline, tetracycline, tilmicosin, and tylosin were 0.03 µg/mL, 0.02 µg/mL, 0.04 µg/mL, and 0.02 µg/mL respectively.â¢The method demonstrated an average recovery rate of over 90% from milk samples with peak values reaching up to 0.100-0.200 µg/mL.
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2,2-Dibromo-3-nitrilopropionamide (DBNPA) is a widely used biocide with potential environmental implications due to its toxicity. This study aimed to investigate the in vivo toxicity of DBNPA in zebrafish (Danio rerio), a model organism in environmental toxicology. Both adult and larval zebrafish were exposed to varying concentrations of DBNPA, and significant morphological changes and mortality rates were observed. The study found that even relatively low concentrations of DBNPA can have detrimental effects on zebrafish embryonic development, and high concentrations resulted in rapid mortality in adult zebrafish and larvae. The LC50 values calculated from this study were 9.3 ppm for adults and 9.1 ppm for larvae, indicating the high toxicity of DBNPA to these organisms. These findings underscore the potential environmental impact of DBNPA and highlight the need for further research into its effects on aquatic ecosystems.
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Desinfectantes , Contaminantes Químicos del Agua , Animales , Desinfectantes/toxicidad , Pez Cebra , Contaminantes Químicos del Agua/toxicidad , Larva , Ecosistema , Embrión no MamíferoRESUMEN
AIM: This study aimed to compare the elemental composition of traditional and flavored hookah tobacco, with a focus on heavy metals. METHODS: We used inductively coupled plasma mass spectrometry (ICP-MS) to analyze the concentrations of 29 elements in the raw tobacco, tobacco ash, hookah water after smoking, and tobacco smoke. RESULTS: The results showed that the traditional tobacco had significantly higher metal concentrations than the flavored tobacco in all samples. Most of the toxic metals (more than 98 %) remained in the smoke of both types of tobacco. The tobacco and hookah smoke contained high levels of harmful metals that can pose health risks to hookah users.â¢ICP-MS provides a comprehensive analysis of multiple elements simultaneously and it allows for precise quantification of metal concentrations in different samples.â¢ICP-MS requires specialized equipment and trained personnel and it may not detect elements present in extremely low concentrations.
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Resistance to synthetic antifungals has become one of the leading public health challenges around the world. Accordingly, novel antifungal products like naturally occurring molecules can be one of the potential ways to reach efficient curative approaches to control candidiasis. This work evaluated the effect of menthol on cell surface hydrophobicity (CSH), biofilm formation, growth, and ergosterol content of Candida glabrata, a yeast with a high resistance against antifungal agents. Disc diffusion method (susceptibility to synthetic antifungals), broth micro-dilution method (Susceptibility to menthol), 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide reduction assay (biofilm formation), High-performance liquid chromatography (HPLC) technique (ergosterol content), and adherence to n-hexadecane (CSH) were employed to determine the influence of menthol against C. glabrata isolates. The minimum inhibitory concentration (MIC) range of menthol versus C. glabrata was 1250-5000 µg/mL (mean ± SD: 3375 ± 1375 µg/mL). The mean rate of C. glabrata biofilm formation was decreased up to 97.67%, 81.15%, 71.21%, 63.72%, 47.53%, 26.31%, and 0.051% at 625, 1250, 2500, 5000, 10 000, 20 000, and 40 000 µg/mL concentrations, respectively. The percentages of CSH were significant in groups treated with MIC/2 (17.51 ± 5.52%) and MIC/4 (26 ± 5.87%) concentrations of menthol. Also, the percentage changes in membrane ergosterol were 15.97%, 45.34%, and 73.40% at 0.125, 0.25, and 0.5 mg/mL concentrations of menthol, respectively, in comparison with untreated control. The results showed the menthol impact versus sessile and planktonic C. glabrata cells, and the interference with ergosterol content, CSH, and biofilm formation, which made it a potent natural antifungal.
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Antifúngicos , Candida glabrata , Antifúngicos/farmacología , Mentol/farmacología , Ergosterol , Pruebas de Sensibilidad Microbiana , Interacciones Hidrofóbicas e Hidrofílicas , BiopelículasRESUMEN
In this study, the degradation of two organophosphate pesticides, namely, propetamphos and azamethiphos, in the presence of Ag+ at different mole ratios was investigated. Moreover, the kinetic and degradation pathways of both chemicals in the range of 0-60 min were explored. Gas chromatography equipped with a thermionic specific detector was used to investigate the pesticide degradation kinetics and mechanism. The results show that the degradation rate of both pesticides follows first-order kinetic. The first-order rate constant and the half-life of reaction were in the range of 0.002-0.143 min-1, 187-2.1 min, and 0.005-0.164 min-1 and 60-1.8 min, for propetamphos and azamethiphos, respectively, at ambient temperature (25 ºC). Because group containing sulfur atom is a better leaving group than group containing nitrogen, the rate of degradation of azamethiphos is higher than propetamphos. In a higher mole ratio of Ag+ to pesticides, the degradation rate was increased, and it is possible to predict the rate of degradation of pesticides according to the chemical composition of leaving group.
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Plaguicidas , Plata , Monitoreo del AmbienteRESUMEN
The drop immerses calcium chloride aqueous solution was utilized to prepare the zero valent iron-doped polyethersulfone beads (PES/ZVI) for the efficient removal of arsenic from apatite-soil treated waters. The proposed beads can assist in promoting uptake efficiency by hindering ZVI agglomeration due to a high porosity and different active sites. The PES/ZVI beads were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and vibrating sample magnetism (VSM). The main objective of this study was to investigate the function of new PES/ZVI beads with an increased removal efficiency for the remediation of arsenic ions from the apatite-soil treated waters. A maximum adsorption removal of 82.39% was achieved when the experiment was performed with 80 mg of adsorbent for a contact time of 180 min. Based on the results, a removal efficiency >90% was obtained after 300 min of shaking time with an arsenic concentration of 20 mg·L-1. The experimental process was fitted with the Langmuir model due to the high R2 (0.99) value compared to the Freundlich model (0.91) with an adsorption capacity of 41.32 mg·g-1. The adsorption process speed was limited by pseudo-second-order (R2 = 0.999) and the adsorption mechanism nature was endothermic and physical.
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Arsénico , Contaminantes Químicos del Agua , Adsorción , Apatitas , Arsénico/análisis , Cloruro de Calcio , Concentración de Iones de Hidrógeno , Iones , Hierro/química , Cinética , Fenómenos Magnéticos , Suelo , Espectroscopía Infrarroja por Transformada de Fourier , Agua/análisis , Contaminantes Químicos del Agua/análisisRESUMEN
Pesticides application is expanding globally as the worldwide population increases demanding a secure and safe food supply. Organophosphorus (OP) pesticides, as a group, are widely used because they are rapidly degraded in the environment and because they have excellent efficacy and an acceptable price point. However, the chemical fate of organophosphorus pesticides is influenced by several factors, including their chemistry in aquatic environments. Among many degradation choices, hydrolysis by metal ions appears to be a good approach. Dissolved metal ions have been shown to promote the hydrolysis of organophosphorus pesticides. Using silver ion, we showed the effectiveness under in vitro and in vivo conditions for this metal ion to decontaminate water polluted by the organophosphorus phosalone. Phosalone was completely degraded in the presence of silver ions in a mole ratio of 7:1 in 20 min. Rainbow trout were divided into experimental groups to investigate the most effective ratio of silver/phosalone for pesticide degradation. Silver ion (2%) at a concentration of 0.75 and 0.1 mL removed phosalone (2%) at concentrations of 0.4 and 0.5 mL. All the rainbow trout survived in these two groups. This experiment suggested that silver ions can be beneficial at ratios in the range of 1:4 to 1:6 by hydrolyzing phosalone by attacking the electron-deficient phosphorus atom in the pesticide.
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Compuestos Organotiofosforados/química , Plaguicidas , Hidrólisis , Iones , Compuestos Organofosforados , PlataRESUMEN
The senescence is proposed as a defense mechanism against many anticancer drugs. This complication is marked by differences in cell appearance and inner structures underlying the impairment in function. In this experiment, doxorubicin-induced senescence was assessed in mesenchymal stem cells (MSCs) isolated from the bone marrow of different-aged Balb/c mice (1, 8, and 16 months old). In addition, doxorubicin kinetics in culture medium were investigated to compare the drug absorption rate by different-aged MSCs. Several methods were exerted including Sandwich ELISA for NF-κB activation, propidium iodide staining for cell cycle analysis, Flow-fluorescent in-situ hybridization (Flow-FISH) assay for telomere length measurement, and specific staining for evaluation of ß-galactosidase. Determination of doxorubicin in a medium was performed by high-performance liquid chromatography technique. Following doxorubicin exposure, cells underwent substantial telomere shortening, cell cycle arresting in G2 phase, and increased ß-galactosidase activity. Interestingly, the enhanced level of NF-κB was observed in all age groups. The highest and lowest sensitivity to telomere shortening attributed to 1- and 8-month-old MSCs, respectively. In consistent with Flow-FISH results, the ß-galactosidase activity was higher in young-aged MSCs after treatment. Statistical analysis indicated a correlation between the reduction of telomere length and cessation in G2 phase. Regarding the obtained kinetics equations, the rate of doxorubicin absorption by all aged MSCs followed the same trend. In conclusion, the changing of some elements involved in doxorubicin-induced senescence can be affected by the age of the cells significantly in young MSCs than two other age groups. Hereupon, these changing patterns can open new insights to develop anticancer therapeutic strategies.
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Senescencia Celular/efectos de los fármacos , Doxorrubicina/farmacología , Células Madre Mesenquimatosas/efectos de los fármacos , Células Madre Mesenquimatosas/metabolismo , FN-kappa B/metabolismo , Animales , Antineoplásicos/farmacología , Puntos de Control del Ciclo Celular/efectos de los fármacos , Diferenciación Celular/efectos de los fármacos , Femenino , Fase G2/efectos de los fármacos , Ratones , Ratones Endogámicos BALB C , Transducción de Señal/efectos de los fármacos , Acortamiento del Telómero/efectos de los fármacos , beta-Galactosidasa/metabolismoRESUMEN
The aim of the present study was to evaluate the acute toxicity as lethal dose 50% (LD50) and sub-acute toxicity of the black caraway Bunium persicum (Bioss) seed essential oil in male Wistar rats. The compounds of B. persicum were identified by GC/MS and amount of each compound was evaluated. 21 different compounds were determined in the essential oil and the main components were: carvone, p-cymene, gamma-terpinene, p-cymene-8-ol, limonene, isoterpinolene, and 2-beta pinene. For acute toxicity evaluation, the animals were randomly divided into nine group (nâ¯=â¯6) and received 500, 1000, 1500, 2000, 2500, 3000, 3500 and 4000â¯mg/kg seed essential oil, respectively and the LD50 value for black caraway seed essential oil was obtained above 4000â¯mg/kg body weight. According to data, treatment with the black caraway seed essential oil sub-acute toxicity study attenuated histopathological changes in lung, liver, kidney, testes and spleen tissues and the results of this study show that the black caraway essential oil can not affect the immune and blood system, important enzymes and vital organs of the body..
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BACKGROUND: Graphene is considered as a wonder material; it is the strongest material on the planet, super-elastic, and conductive. Its application in biomedicine is huge, with a multibillion-dollar industry, and will revolutionize the diagnostic and treatment of diseases. However, its safety and potential toxicity is the main challenge. METHODS: This study assessed the potential toxicity of graphene oxide nanoplatelets (GONs) in an in vivo animal model using systemic, hematological, biochemical, and histopathological examinations. Normal saline (control group) or GONs (3-6 layers, lateral dimension=5-10 µm, and thickness=0.8-2 nm) at dose rate of 50, 150, or 500 mg/kg were intraperitoneally injected into adult male Wistar rats (n=5) every 48 hours during 1 week to receive each animal a total of four doses. The animals were allowed 2 weeks to recover after the last dosing. Then, animals were killed and the blood was collected for hematological and biochemical analysis. The organs including the liver, kidney, spleen, lung, intestine, brain, and heart were harvested for histopathological evaluations. RESULTS: The results showed GONs prevented body weight gain in animals after 21 days, treated at 500 mg/kg, but not in the animals treated at 150 or 50 mg/kg GONs. The biochemical analysis showed a significant increase in total bilirubin, with a significant decrease in triglycerides and high-density lipoprotein in animals treated at 500 mg/kg. Nonetheless, other hematological and biochemical parameters remained statistically insignificant in all GONs treated animals. The most common histopathological findings in the visceral organs were granulomatous reaction with giant cell formation and accumulation of GONs in capsular regions. Also, small foci of neuronal degeneration and necrosis were the most outstanding findings in the brain, including the cerebellum. CONCLUSION: In conclusion, this study shows that GONs without functionalization are toxic. The future study is a comparison of the functionalized with non-functionalized GONs.
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Grafito/toxicidad , Nanopartículas/toxicidad , Pruebas de Toxicidad , Animales , Peso Corporal/efectos de los fármacos , Grafito/administración & dosificación , Inyecciones , Masculino , Nanopartículas/administración & dosificación , Nanopartículas/ultraestructura , Especificidad de Órganos , Ratas Wistar , Espectrometría Raman , Difracción de Rayos XRESUMEN
The authors describe a zinc-based metal-organic framework/polyethersulfone nanocomposite (TMU-4/PES) coating deposited on a stainless steel wire via a single-phase inversion method. The nanocomposite represents a novel fiber coating for headspace solid-phase microextraction of organophosphorous pesticides (OPPs) from environmental water and soil samples. The synergistic effects of the high surface area and unique porous structure of TMU-4 as well as the rich π electron stacking and mechanical attributes of the PES polymer result in a high affinity of the composite for OPPs. Following thermal desorption, the OPPS were quantified by gas chromatography with a nitrogen-phosphorus detector. The preparation of the coating is simple, and the coated fiber is highly stable and reusable in that it can be used in about 100 consecutive extractions/desorption cycles. A central composite design was used for assessing the effect of the experimental parameters on the extraction process. Under optimized conditions, the limits of detection are in the 5-8 ng mL-1 range for the OPPs diazinon, fenitrothion, malathion and chlorpyrifos. The average repeatability and fiber-to-fiber reproducibility are 6.5% and 8.7%, respectively. The method was applied to the trace determination of OPPs in (spiked) water and soil samples where it gave good recovery (88-108%) and satisfactory reproducibility (5.9-10.1%). Graphical abstract A zinc-based metal-organic framework/polyethersulfone nanocomposite coating was prepared on a stainless steel wire via phase inversion. It was used as a novel fiber coating for headspace solid phase microextraction of organophosphorous pesticides from water and soil samples.
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The concentrations of polychlorinated biphenyls (PCBs) were assessed at four sites in Khour-e-Mousa (Mah-Shahr), Iran. Sea water, sediment and fish (cynoglossus bilineatus) samples were taken at each site and were analysed for PCB levels. To investigate the possible source of PCBs found in fish samples, sediments and waters were collected from four sites (D1, D2, D3, and D4) and studied. The relationship between PCB concentrations in sediment, water and fish is discussed. The results indicate that PCBs are detected in all fish samples and its concentration range from 3.2 to 102.7 µg kg(-1) dry weight and 5.4-149.7 µg kg(-1) dry weight in cold and warm seasons, respectively. The D2 and D4 sites were found to have the highest and lowest levels of PCB concentrations, respectively. Total congener PCB (CB, 28, 52, 44, 101, 149, 118, 153, 138, and 180) concentrations at the sediment samples for D1, D2, D3, and D4 sites ranged from 1.6 to 30.9 µg kg(-1) dry weight and 2.3-47.1 µg kg(-1) dry weight in cold and warm seasons, respectively. The total PCB concentrations for D2 site were found to be significantly higher than other three sites. Total water congener PCB (CB, 28, 52, 44, 101, 149, 118, 153, 138, and 180) concentrations ranged from 0.01 to 0.25 µg L(-1) and 0.02-0.39 µg L(-1) in cold and warm seasons, respectively.
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Peces/metabolismo , Sedimentos Geológicos/química , Bifenilos Policlorados/análisis , Agua de Mar/química , Contaminantes Químicos del Agua/análisis , Animales , Monitoreo del Ambiente , Irán , Bifenilos Policlorados/metabolismo , Estaciones del Año , Contaminantes Químicos del Agua/metabolismo , Contaminación Química del Agua/estadística & datos numéricosRESUMEN
This study reports the feasibility of applying directly suspended liquid-phase microextraction (DSLPME)-gas chromatography detection for the pre-concentration and determination of low levels of eight polychlorinated biphenyls (PCBs) in aqueous samples. The technique requires minimal sample preparation, analysis time and solvent consumption and represents significant advantages over conventional analytical methods. The experimental parameters such as salt content, sample temperature, stirring rate, extraction time, micro-drop volume and breakthrough volume were investigated and found to have significant influences on DSLPME. Under the optimal experimental conditions, the enrichment factor ranged from 578 to 729, and the recovery was above 93 %. Calibration curves possessed good linearity (R(2) > 0.99) over a wide concentration range of 0.1-10.0 µg L(-1) with limits of detection ranging from 0.01 to 0.07 µg L(-1). The relative standard deviations for 1.0 µg L(-1) of PCBs in water by using internal standard were in the range 2-14 % (n = 3). The proposed simple, accurate and sensitive analytical method was applied successfully to the determination of trace amounts of PCBs in water samples.
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Monitoreo del Ambiente/métodos , Bifenilos Policlorados/análisis , Contaminantes Químicos del Agua/análisis , Cromatografía de Gases , Microextracción en Fase LíquidaRESUMEN
The degradation of some organophosphorus pesticides (OPPs) in the presence of metal ions was studied by (31)P-NMR spectroscopy. Both (31)P-NMR and gas chromatography/mass spectroscopy results were used in order to determine the nature of metabolites formed after degradation. The degraded organophosphorus pesticide were investigated for chlorpyrifos and phoxim in the presence of several metal ions including Hg(2+), Cu(2+), Cd(2+), Ni(2+), Pb(2+), and Ag(+). (31)P-NMR results indicated Ag(+) and Hg(2+) ion promoted degradation of OPPs and other metal ions formed complex with OPPs and cannot degrade OPPs. We found that the degradation of chlorpyrifos and phoxim with Ag(+) or Hg(2+) led to the formation of O,O-diethyl-O-methyl phosphorothionate, (C(2)H(5)O)(2)(CH(3)O)PS, at metal ion/pesticide mole ratios ≤1.0 and completely decomposed at a higher mole ratio of 10. Finally, the method was successfully applied to the degradation study of a number of technical and formulated pesticides in the presence of Ag(+) ion at a metal ion/pesticide mole ratio of 10.
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Metales/química , Compuestos Organofosforados/química , Plaguicidas/química , Hidrólisis , Iones/química , Espectroscopía de Resonancia MagnéticaRESUMEN
A simple and rapid method based on homogeneous liquid-liquid extraction coupled to HPLC with fluorescence detection was developed for the determination of aflatoxin B1 (AFB1) in the rice and grain samples after post-column derivatization. The proposed method eliminated the use of immunoaffinity columns for clean-up in the determination of AFB1. The parameters affecting recovery and preconcentration such as type and volume of organic solvent, volume ratio of water/methanol, concentration of phase separator reagent and extraction time were optimized. Under the optimized conditions, the calibration graph was linear in the concentration range of 0.01-1.0 ng/g with the detection limit of 0.003 ng/g. This method was successfully applied for the analysis of AFB1 in different cereal samples.