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1.
Data Brief ; 55: 110563, 2024 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-38911138

RESUMEN

Dryingfish is a simple and economical way to process the catch. It creates a profitable business for coastal communities by providing a market for their catches, even during periods of abundance. It's a traditional method to preserve fish, especially valuable in regions where fresh fish isn't readily available or affordable throughout the year. This dataset provides a rich resource of 8290 images specifically designed for machine learning applications. It focuses on the five most popular types of dried seafood in India: prawns (shrimp), small anchovies (tingali), golden anchovies (mandeli), mackerel (bangada), and Bombay duck (bombil). To ensure high-quality data for machine learning applications for Identification and classification of different dried fish varieties, the dataset features a diverse set of images in singles and in bulk for each category. The dataset utilizes standardized lighting, background, and object pose for optimal machine learning performance. This rich dataset empowers researchers and data scientists to leverage machine learning for various applications in the Indian dried fish industry.Overall, the Dried Fish Dataset for Indian Seafood aims to leverage machine learning to improve the standardization, quality control, safety, and efficiency of the Indian dried fish industry.

2.
Chemosphere ; 351: 141197, 2024 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-38244866

RESUMEN

One of the main gaseous pollutants released by chemical production industries are benzene, toluene and xylene (BTX). These dangerous gases require immediate technology to combat them, as they put the health of living organisms at risk. The development of heterogeneous photocatalytic oxidation technology offers several viewpoints, particularly in gaseous-phase decontamination without an additional supply of oxidants in air at atmospheric pressure. However, difficulties such as low quantum efficiency, ability to absorb visible light, affinity towards CO2 and H2O synthesis, and low stability continue to limit its practical use. This review presents recent advances in dry-phase heterogeneous photodegradation as an advanced technology for the practical removal of BTX molecules. This review also examines the impact of low-cost light sources, the roles of the active sites of photocatalysts, and the feasible concentration range of BTX molecules. Numerous studies have demonstrated a significant improvement in the efficiency of the photodegradation of volatile organic compounds by enhancing the photocatalytic reactor system and other factors, such as humidity, temperature, and flow rate. The mechanism for BTX photodegradation based on density functional theory (DFT), electron paramagnetic resonance (EPR) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) investigations is also discussed. Finally, the present research complications and anticipated future developments in the field of heterogeneous photocatalytic oxidation technology are discussed.


Asunto(s)
Benceno , Xilenos , Benceno/química , Xilenos/química , Tolueno/química , Catálisis , Luz , Gases
3.
Electrophoresis ; 45(3-4): 212-217, 2024 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36695087

RESUMEN

A procedure to determine albendazole and ivermectin in veterinary formulations, like tablet, bolus, oral suspensions, and injections by micellar liquid chromatography, has been developed. Sample preparation was a batch solid-to-liquid extraction in mobile phase, consisting of a stirring step (15 min), followed by ultrasonication (15 min) and filtration of the obtained supernatant, to reach a target concentration of 2 mg/L for both analytes. Using a mobile phase of 0.15 M sodium dodecyl sulfate-6% 1-pentanol buffered at pH 3 with a 0.01 M phosphate salt, running at 1 mL/min through a C18 column, both drugs were resolved in less than 10 min. Absorbance detection wavelength was 292 nm. Procedure was validated by the guidelines of the International Council on Harmonization in terms of specificity, calibration range (0.025-5 mg/L), trueness (97.8%-102.6%), precision (<2.2%), and system suitability. The method was found easy-to-handle, low cost, safe, green, and with high sample-throughput, thus useful for routine analysis. Therefore, it represents a valuable alternative for quality control of veterinary formulations. It was applied to samples of veterinary formulations purchased from local chemists and veterinarians, and label claims were inside the acceptance criteria (95%-105%).


Asunto(s)
Albendazol , Ivermectina , Micelas , Cromatografía Liquida/métodos
4.
Dalton Trans ; 52(36): 12832-12844, 2023 Sep 19.
Artículo en Inglés | MEDLINE | ID: mdl-37622345

RESUMEN

Green energy production is becoming increasingly important in mitigating the effects of climate change, and the photocatalytic approach could be a potential solution. However, the main barriers to its commercialization are ineffective catalysis due to recombination, poor optical absorption, and sluggish carrier migration. Here, we fabricated a two-dimensional (2D) reduced niobium oxide photocatalyst synthesized by an in situ thermal method followed by copper incorporation. Compared to its counterparts, pure Nb2O5 (0.092 mmol g-1 CO) and r-Nb2O5 (0.216 mmol g-1 CO), the strongly bonded Cu/r-Nb2O5 (0.908 mmol g-1) sample produced an exceptional amount of CO. The separation of charge carriers and efficient use of light resulted in a remarkable photocatalytic performance. The acceptor levels were created by the Cu nanophase, and the carrier trapping states were created by the oxygen vacancies. This mechanism was supported by ESR and DRIFT analyses, which showed that enough free radicals were produced. This study opens up new possibilities for developing efficient photocatalysts that will generate green fuel.

5.
ACS Omega ; 6(2): 1523-1533, 2021 Jan 19.
Artículo en Inglés | MEDLINE | ID: mdl-33490812

RESUMEN

Copper manganese oxides (CMO) with CuMn2O4 composition are well-known catalysts, which are widely used for the oxidative removal of dangerous chemicals, e.g., enhancing the CO to CO2 conversion. Their catalytic activity is the highest, close to those of the pre-crystalline and amorphous states. Here we show an easy way to prepare a stable CMO material at the borderline of the amorphous and crystalline state (BAC-CMO) at low temperatures (<100 °C) followed annealing at 300 °C and point out its excellent catalytic activity in CO oxidation reactions. We demonstrate that the temperature-controlled decomposition of [Cu(NH3)4](MnO4)2 in CHCl3 and CCl4 at 61 and 77 °C, respectively, gives rise to the formation of amorphous CMO and NH4NO3, which greatly influences the composition as well as the Cu valence state of the annealed CMOs. Washing with water and annealing at 300 °C result in a BAC-CMO material, whereas the direct annealing of the as-prepared product at 300 °C gives rise to crystalline CuMn2O4 (sCMO, 15-40 nm) and ((Cu,Mn)2O3, bCMO, 35-40 nm) mixture. The annealing temperature influences both the quantity and crystallite size of sCMO and bCMO products. In 0.5% CO/0.5% O2/He mixture the best CO to CO2 conversion rates were achieved at 200 °C with the BAC-CMO sample (0.011 mol CO2/(m2 h)) prepared in CCl4. The activity of this BAC-CMO at 125 °C decreases to half of its original value within 3 h and this activity is almost unchanged during another 20 h. The BAC-CMO catalyst can be regenerated without any loss in its catalytic activity, which provides the possibility for its long-term industrial application.

6.
Curr Org Synth ; 17(5): 367-381, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-32264812

RESUMEN

BACKGROUND: The search for new antimicrobial drugs is a never-ending task due to microbial resistance to the existing drugs. Antioxidants are essential to prevent free radical reactions which lead to chronic diseases to humankind. OBJECTIVE: The present studies were aimed at synthesis, characterization, antimicrobial and antioxidant activities of pyridine and benzoisothiazole decorated chalcones. MATERIALS AND METHODS: FTIR spectra were recorded using KBr pellets on Shimadzu FT-IR spectrophotometer. 1H and 13C NMR spectra were recorded on Bruker 400 MHz spectrometer. Antimicrobial activity of the synthesized chalcones was found to be good against different bacterial and fungal strains. Antioxidant activity was studied in terms of 2,2-diphenyl-1-picrylhydrazyl, hydroxyI and superoxide radical scavenging activities. Molecular docking was studied using Discovery Studio Visualizer Software, version 16 whereas Autodock Vina program was used to predict the toxicity profile of the compounds using FAFDrugs2 predictor. RESULTS AND DISCUSSION: The compounds 5c, 5d & 6c showed good antioxidant activities. The insilico molecular docking study supports the experimental results and demonstrated that the chalcones 5d, 6a and 7a are the most active among the synthesized derivatives. CONCLUSION: Prediction of pharmacokinetic parameters and molecular docking studies suggest that the synthesized chalcones have good pharmacokinetic properties to act as lead molecules in the drug discovery process.

7.
Antibiotics (Basel) ; 9(2)2020 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-32075155

RESUMEN

Mebendazole is an anthelmintic drug used in cattle production. However, residues may occur in produced food and in excretions, jeopardizing population health. A method based on micellar liquid chromatography (MLC) was developed to determine mebendazole in dairy products (milk, cheese, butter, and curd) and nitrogenous waste (urine and dung) from bovine animals. Sample treatment was expedited to simple dilution or solid-to-liquid extraction, followed by filtration and direct injection of the obtained solution. The analyte was resolved from matrix compounds in less than 8 min, using a C18 column and a mobile phase made up of 0.15 M sodium dodecyl sulfate (SDS)-6% 1-pentanol phosphate buffered at pH 7, and running at 1 mL/min under isocratic mode. Detection was performed by absorbance at 292 nm. The procedure was validated according to the guidelines of the EU Commission Decision 2002/657/EC in terms of: specificity, method calibration range (from the limit of quantification to 25-50 ppm), sensitivity (limit of detection 0.1-0.2 ppm; limit of quantification, 0.3-0.6 ppm), trueness (92.5-102.3%), precision (<7.5%, expressed at RSD), robustness, and stability. The method is reliable, sensitive, easy-to-handle, eco-friendly, safe, inexpensive, and provides a high sample-throughput. Therefore, it is useful for routine analysis as a screening or quantification method in a laboratory for drug-residue control.

8.
Bioanalysis ; 11(8): 713-726, 2019 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-30994011

RESUMEN

Aim: The macrolide antibiotic rifampicin is prescribed against several infections, like tuberculosis disease. This drug decays to rifampicin quinone. Results/methodology: The biological fluids were diluted in a micellar solution and directly injected. Using a C18 column and a mobile phase of 0.15 M SDS-6% 1-pentanol phosphate-buffered at pH 7, running at 1 ml/min, the analytes were resolved in less than 15 min. The detection was by absorbance at 337 nm. Method was validated by the guidelines of the European Medicines Agency. Decomposition of rifampicin to rifampicin quinone was also studied. Discussion/conclusion: Procedure is rapid, easy-to-handle, economic, eco-friendly and with a high sample throughput. It was successfully used to monitor rifampicin in the plasma and urine of tubercular patients.


Asunto(s)
Antibióticos Antituberculosos/uso terapéutico , Rifampin/uso terapéutico , Tuberculosis/sangre , Tuberculosis/orina , Antibióticos Antituberculosos/farmacología , Europa (Continente) , Guías como Asunto , Humanos , Rifampin/farmacología , Tuberculosis/patología
9.
Curr Org Synth ; 16(2): 288-293, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31975678

RESUMEN

AIM AND OBJECTIVE: The present study was performed with the aim to develop an efficient and environmentally benign protocol for the synthesis of biologically siginifcant 3, 4-dihydropyrano[c]chromenes using a new catalytic material. The protocol involves the use of a reusable, environment friendly materials and solvents with operational simplicity. MATERIALS AND METHODS: Carbon microsphere supported copper nanoparticles (Cu-NP/C) prepared from loaded cation exchange resin were synthesized, characterized with well versed analytical techniques such as XRD, SEM and Raman spectroscopy and the synthesized material was used as a catalyst for the environmentally benign synthesis of 3,4-dihydropyrano[c]chromenes. RESULTS: The formation of carbon microsphere supported copper nanoparticles (Cu-NP/C) prepared from loaded cation exchange resin was confirmed by XRD, SEM and Raman spectroscopy which was employed as a heterogeneous material for the synthesis of 3,4-dihydropyrano[c]chromenes. The products formed were characterized by the analysis of spectroscopic data - NMR, IR and mass. The safe catalytic system offers several advantages including operational simplicity, environmental friendliness, high yield, and reusability of catalyst and green chemical transformation. CONCLUSION: Herein we report an easy and efficient protocol for the one-pot synthesis of dihydropyrano[ c]chromenes using environmentally benign MCR approach in ethanol as the green solvent. The method developed herein constitutes a valuable addition to the existing methods for the synthesis of titled compounds.

10.
Sensors (Basel) ; 18(10)2018 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-30322092

RESUMEN

Quinoxaline-based novel acid-responsive probe Q1 was designed on the basis of a conjugated donor-acceptor (D-A) subunit. Q1 shows colorimetric and fluorometric changes through protonation and deprotonation in dichloromethane. With the addition of the trifluoroacetic acid (TFA), UV-vis absorption spectral changes in peak intensity of Q1 was observed. Moreover, the appearance of a new peaks at 284 nm 434 nm in absorption spectra with the addition of TFA indicating protonation of quinoxaline nitrogen and form Q1.H⁺ and Q1.2H⁺. The emission spectra display appearance of new emission peak at 515 nm. The optical property variations were supported by time resolved fluorescence studies. The energy band gap was calculated by employing cyclic voltammetry and density functional calculations. Upon addition of triethylamine (TEA) the fluorescence emission spectral changes of Q1 are found to be reversible. Q1 shows color changes from blue to green in basic and acidic medium, respectively. The paper strip test was developed for making Q1 a colorimetric and fluorometric indicator.


Asunto(s)
Colorimetría/métodos , Quinoxalinas/química , Espectrometría de Fluorescencia/métodos , Espectrofotometría Ultravioleta/métodos , Color , Colorimetría/instrumentación , Electroquímica/métodos , Etilaminas/química , Colorantes Fluorescentes/química , Concentración de Iones de Hidrógeno , Nitrilos/química , Protones , Quinoxalinas/síntesis química , Tiras Reactivas/química , Espectrometría de Fluorescencia/instrumentación , Ácido Trifluoroacético/química
11.
Dalton Trans ; 47(21): 7237-7244, 2018 May 29.
Artículo en Inglés | MEDLINE | ID: mdl-29756147

RESUMEN

We report the coating of metal-free graphitic carbon nitride (g-C3N4) onto titanium dioxide (TiO2) nanorods via a thermal evaporation method. Prior to g-C3N4 coating, TiO2 nanoclusters were grown on TiO2 nanorods to enhance the surface area by dipping in a TiCl3 solution for 12, 24 and 36 h. The prepared films were analyzed to assess the improvement in absorbance and reduction in recombination losses. Nanoclustered TiO2 grown for 24 h and then coated with a g-C3N4 film (i.e., TC_24h_CN) had the highest photocurrent of 235 and 290 µA, respectively, when measured by transient photocurrent and linear sweep voltammetry techniques. The enhanced performance resulted from a reduced recombination of electron-hole pairs. The TC_24h_CN film displayed an excellent photoresponse over 15 h of exposure to visible light and hence could potentially be used in water purification device technology.

12.
RSC Adv ; 8(59): 33600-33613, 2018 Sep 28.
Artículo en Inglés | MEDLINE | ID: mdl-35548797

RESUMEN

We engineered high aspect ratio Fe2O3 nanorods (with an aspect ratio of 17 : 1) coated with g-C3N4 using a sequential solvothermal method at very low temperature followed by a thermal evaporation method. Here, the high aspect ratio Fe2O3 nanorods were directly grown onto the FTO substrate under relatively low pressure conditions. The g-C3N4 was coated onto a uniform Fe2O3 nanorod film as the heterostructure, exhibiting rational band conduction and a valence band that engaged in surface photoredox reactions by a direct z-scheme mechanism. The heterostructures, particularly 0.75g-C3N4@Fe2O3 nanorods, exhibited outstanding photocatalytic activities compared to those of bare Fe2O3 nanorods. In terms of 4-nitrophenol degradation, 0.75g-C3N4@Fe2O3 nanorods degraded all of the organic pollutant within 6 h under visible irradiation at a kinetic constant of 12.71 × 10-3 min-1, about 15-fold more rapidly than bare Fe2O3. Further, the hydrogen evolution rate was 37.06 µmol h-1 g-1, 39-fold higher than that of bare Fe2O3. We suggest that electron and hole pairs are efficiently separated in g-C3N4@Fe2O3 nanorods, thus accelerating surface photoreaction via a direct z-scheme under visible illumination.

13.
Phys Chem Chem Phys ; 19(41): 28207-28215, 2017 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-29026899

RESUMEN

Titanium dioxide (TiO2) with exposed (001) facets (TiO2(001)) has attractive photocatalytic properties. However, the high recombination rate of the photo-excited charge carriers on this surface often limits its application. Here, we report that a few-layered 1T-MoS2 coating on TiO2(001) nanosheets (abbreviated as MST) can be a promising candidate that overcomes some of the challenges of TiO2(001). Computational and experimental results demonstrate that MST as a photocatalyst exhibits a significantly low-charge recombination rate as well as excellent long-term durability. The synthesized MST 2D nanocomposites show a 31.9% increase in photocatalytic activity for hydrogen (H2) production relative to the counterpart TiO2(001). MST offers a new route for further improvement of the photocatalytic activity of TiO2 with exposed high energy facets.

14.
Bioorg Med Chem Lett ; 27(16): 3891-3896, 2017 08 15.
Artículo en Inglés | MEDLINE | ID: mdl-28676272

RESUMEN

Some thiazolyl hydrazones were synthesized by one pot reaction of thiophene-2-carbaldehyde or 2, 4-dichlorobenzaldehyde, thiosemicarbazide and various phenacyl bromides which were preliminarily screened for in vitro antioxidant and antifungal activities. Excellent DPPH and H2O2 radical scavenged antioxidant activities were observed with almost all the tested compounds. Compounds 4a, 4b, 4c, 4e, 4f and 4i showed comparable DPPH scavenged antioxidant potential (90.26-96.56%) whereas H2O2 scavenged antioxidant activity (90.98-92.08%) was noticeable in case of 4a and 4f; showing significant antioxidant potential comparable with the standard ascorbic acid (95.3%). In vitro antifungal activity of synthesized compounds against fungal species Candida albicance, Aspergillus niger and Aspergillus flavus was found to be moderate to good as compared with the standard fluconazole and MIC values were found in the range of 3.12-25µg/mL. Molecular docking studies revealed that the compounds 4a, 4b and 4c have a potential to become lead molecules in drug discovery process. In silico ADMET study was also performed for predicting pharmacokinetic and toxicity profile of the synthesized antioxidants which expressed good oral drug like behaviour and non-toxic nature.


Asunto(s)
Antifúngicos/farmacología , Antioxidantes/farmacología , Simulación por Computador , Hidrazonas/farmacología , Antifúngicos/síntesis química , Antifúngicos/química , Antioxidantes/síntesis química , Antioxidantes/química , Aspergillus flavus/efectos de los fármacos , Aspergillus niger/efectos de los fármacos , Candida/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Hidrazonas/síntesis química , Hidrazonas/química , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Relación Estructura-Actividad
15.
Sci Rep ; 6: 31147, 2016 08 08.
Artículo en Inglés | MEDLINE | ID: mdl-27498979

RESUMEN

A one-dimensional (1D) nanostructure having a porous network is an exceptional photocatalytic material to generate hydrogen (H2) and decontaminate wastewater using solar energy. In this report, we synthesized nanoporous 1D microrods of graphitic carbon nitride (g-C3N4) via a facile and template-free chemical approach at room temperature. The use of concentrated acids induced etching and lift-off because of strong oxidation and protonation. Compared with the bulk g-C3N4, the porous 1D microrod structure showed five times higher photocatalytic degradation performance toward methylene blue dye (MB) under visible light irradiation. The photocatalytic H2 evolution of the 1D nanostructure (34 µmol g(-1)) was almost 26 times higher than that of the bulk g-C3N4 structure (1.26 µmol g(-1)). Additionally, the photocurrent stability of this nanoporous 1D morphology over 24 h indicated remarkable photocorrosion resistance. The improved photocatalytic activities were attributed to prolonged carrier lifetime because of its quantum confinement effect, effective separation and transport of charge carriers, and increased number of active sites from interconnected nanopores throughout the microrods. The present 1D nanostructure would be highly suited for photocatalytic water purification as well as water splitting devices. Finally, this facile and room temperature strategy to fabricate the nanostructures is very cost-effective.

16.
Mol Divers ; 20(3): 763-70, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-27222148

RESUMEN

An ethylene glycol promoted catalyst-free practically efficient and sustainable approach has been developed for the synthesis of several benzylidene-bis-(4-hydroxycoumarin)s and 4,[Formula: see text]-(arylmethylene)-bis(3-methyl-1-phenyl-1H-pyrazol-5-ol)s by the pseudo three-component reaction of an aldehyde with 4-hydroxycoumarin and 3-methyl-1-phenylpyrazol-5-one, respectively. Inexpensive, non-toxic, and easily available ethylene glycol used as the reaction solvent and promoter renders an efficient protocol in terms of catalyst-free reaction conditions, short reaction time, high yield, practical utility, and green approach.


Asunto(s)
Cumarinas/síntesis química , Glicol de Etileno/química , Pirazoles/síntesis química , Catálisis , Cumarinas/química , Tecnología Química Verde/métodos , Estructura Molecular , Pirazoles/química , Estereoisomerismo
17.
Phytother Res ; 30(3): 412-7, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26648323

RESUMEN

The present study was carried out to evaluate anti-Helicobacter pylori and its associated urease activity of labdane diterpenoids isolated from Andrographis paniculata. A molecular docking analysis was performed by using ArgusLab 4.0.1 software. The results obtained indicate that compound A possesses strong inhibition to H. pylori, 28 ± 2.98 (minimum inhibitory concentration, 9 µg/mL), and its urease, 85.54 ± 2.62% (IC50 , 20.2 µg/mL). Compounds B, C, and D also showed moderate inhibition to H. pylori and its urease. The obtained results were in agreement with the molecular docking analysis of compounds. The phytochemicals under investigation were found to be promising antibacterial agents. Moreover, the isolated compounds can be considered as a resource for searching novel anti-H. pylori agents possessing urease inhibition.


Asunto(s)
Andrographis/química , Antibacterianos/farmacología , Diterpenos/farmacología , Helicobacter pylori/efectos de los fármacos , Extractos Vegetales/farmacología , Ureasa/antagonistas & inhibidores , Antibacterianos/aislamiento & purificación , Proteínas Bacterianas/antagonistas & inhibidores , Diterpenos/aislamiento & purificación , Helicobacter pylori/enzimología , Helicobacter pylori/crecimiento & desarrollo , Pruebas de Sensibilidad Microbiana , Simulación del Acoplamiento Molecular , Extractos Vegetales/química
18.
Eur J Med Chem ; 90: 707-31, 2015 Jan 27.
Artículo en Inglés | MEDLINE | ID: mdl-25506810

RESUMEN

Indazoles is an important class of heterocyclic compounds having a wide range of biological and pharmaceutical applications. There is enormous potential in the synthesis of novel heterocyclic systems to be used as building blocks for the next generation of pharmaceuticals as anti-bacterial, anti-depressant and anti-inflammatory. Fused aromatic 1H and 2H-indazoles are well recognized for anti-hypertensive and anti-cancer properties. The present review focuses on novel routes of their synthesis and various biological activities.


Asunto(s)
Indazoles/síntesis química , Indazoles/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Antineoplásicos/síntesis química , Antineoplásicos/química , Antineoplásicos/farmacología , Antipsicóticos/síntesis química , Antipsicóticos/química , Antipsicóticos/farmacología , Proliferación Celular/efectos de los fármacos , Dolor Crónico/tratamiento farmacológico , Humanos , Indazoles/química , Estructura Molecular , Narcóticos/síntesis química , Narcóticos/química , Narcóticos/farmacología
19.
Dalton Trans ; 43(33): 12514-27, 2014 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-25001639

RESUMEN

Graphitic carbon nitride (g-C3N4) was hybridized with CdS nanoparticles and reduced graphene oxide (RGO) sheets using a facile chemical method, for the application of catalytic photodegradation of Rhodamine B and Congo red dyes under irradiation with UV and visible light. Fourier-transform infrared (FTIR) spectroscopy and X-ray photoemission spectroscopy (XPS) analyses confirmed the formation of pure g-C3N4, as well as g-C3N4/CdS, g-C3N4/RGO, and g-C3N4/CdS/RGO composites. The large surface area of the g-C3N4/CdS/RGO composite (70.42 m(2) g(-1)) resulted in rapid dye adsorption onto the surface of the photocatalyst, leading to effective photodegradation of organic pollutants. The addition of CdS and RGO increased the photocatalytic activity of g-C3N4 by a factor of approximately twenty compared with that of the commercially available TiO2 catalyst under visible light, and the g-C3N4/CdS/RGO composite was found to significantly enhance the catalytic effect compared with pure g-C3N4 and with the g-C3N4/CdS and g-C3N4/RGO composites. The superior photocatalytic activity of the g-C3N4/CdS/RGO composite is attributed to enhanced separation of the photogenerated electron-hole pairs, as well as increased visible-light absorption. The improved transport of photoelectrons was consistent with the results of transient photocurrent measurements. Therefore, g-C3N4/CdS/RGO composites using a facile method are applicable to the development of high-efficiency photocatalytic devices for industrial applications.

20.
Sci Pharm ; 80(2): 379-91, 2012.
Artículo en Inglés | MEDLINE | ID: mdl-22896824

RESUMEN

A simple, rapid and precise method was developed for the quantitative estimation of prasugrel hydrochloride in pharmaceutical dosage form. A chromatographic separation of prasugrel and its degradants was achieved with Zorbax XDB C(8), 150 × 4.6 mm, 3.5µm analytical column using aqueous solution of 0.05 M ammonium acetate pH 4.5 with acetic acid-acetonitrile (40:60 v/v). The instrumental settings include flow rate of 1.0 ml/min, column temperature at 30°C and detector wavelength of 254 nm using a photodiode array detector. Theoretical plates for prasugrel were 7023. Tailing factor for prasugrel was 1.11. Prasugrel was exposed to thermal, photolytic, hydrolytic and oxidative stress conditions, and the stressed samples were analyzed by the proposed method. Peak homogeneity data of prasugrel was obtained using photodiode array detector in the stressed sample chromatograms, which demonstrated the specificity of the method for the estimation in presence of degradants. The described method showed excellent linearity over a range of 10-300 µg/ml for prasugrel. The correlation coefficient is 0.999. The relative standard deviation of peak area for six measurements is always less than 2%. Overall, the proposed method was found to be suitable and accurate for quantitative determination and stability study of prasugrel in pharmaceutical dosage form.

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