Chemical composition and biological potential of seed oil and leaf extracts of Henophyton deserti Coss. & Durieu

Henophyton deserti was characterized in respect to its chemical composition, antioxidant potential and antimicrobial activity. Fourteen compounds were identified by LC/MS, GC/MS, and GC in leaf and seed extracts. Total flavonoids ranged between 45.66 and 181.2 mg QE g^?1 and 2.03 and 38.95 mg QE g^?1 dry weight (dw) in leaf and seed polar extracts, respectively. Rutin, Kaempferol 3-rutinoside, Diosmetin 7-O-Glucoside, and Acacetin 7-O-Glucoside flavonoids were tentatively identified in this plant. The profile of seed fatty acids revealed oleic acid (C18:1, 27%), linoleic acid (C18:2, 12%) and linolenic acid (C18:3, 17%). The highest antioxidant activities of 85.2% and 67.5% were obtained with methanol and ethyl acetate leaf extracts. All H. deserti extracts were active against at least one of the tested bacteria, leaf ethyl acetate extract showed the lowest MIC of 0.156 mg ml^?1. Only seed ethyl acetate extract showed antifungal activity with a MIC of 2.5 mg ml^?1.     

Copper(II)–neocuproine reagent for spectrophotometric determination of captopril in pure form and pharmaceutical formulations

A simple, rapid, sensitive and accurate spectrophotometric method for the determination of captopril in pure form and pharmaceutical formulations is developed. The procedure is based on the reaction of copper(II) with captopril in the presence of neocuproine (NC) (2,9-dimethyl-1,10-phenanthroline) reagent in acetate buffer at pH 5.0. Copper(II) is reduced easily by captopril to Cu(I)–neocuproine complex, which shows an absorption maximum at 448 nm. Beer’s law was obeyed in the concentration range 0.3–3.0 μg mL^?1 with a minimum detection limit (LOD) of 0.039 μg mL^?1 and a quantification limit (LOQ) of 0.129 μg mL^?1. For more accurate results, Ringbom optimum concentration ranges was 0.5–2.7 μg mL^?1. The apparent molar absorbtivity and Sandell sensitivity were calculated. The validity of the proposed method was tested by analyzing the pure and pharmaceutical formulations and compared well with those obtained by the official method and demonstrated good accuracy and precision.     

Nano TiO2-based preconcentration for the speciation analysis of inorganic selenium by using ion chromatography with conductivity detection

A simple, sensitive, and cost-effective analytical method was developed for the speciation analysis of inorganic selenium by combining a nano-TiO₂ preconcentration with an ion chromatography-conductivity detection (IC-CD) system. The experimental conditions for the simultaneous adsorption and desorption of Se(IV) and Se(VI) were carefully investigated. Under the established optimum condition, the Se(IV) and Se(VI) ions could been simultaneously adsorbed onto the nano-TiO₂ surface at pH 4.0, and then effectively desorbed by 0.1 M sodium hydroxide eluent. The adsorption process was fast and reached adsorption equilibrium within 10 min. The nano-TiO₂ also exhibited high adsorption capacity with 11.3 mg g^? 1 for Se(IV) and 8.34 mg g^? 1 for Se(VI). The enrichment factors for Se(IV) and Se(VI) were calculated to be 39 and 30, respectively, with sample volume of 50 mL. The detection limits (3σ) were 0.8 μg L^? 1 for Se(IV) and 0.4 μg L^? 1 for Se(VI), which were sensitive enough for the routine analysis of water and drink samples. The relative standard deviation was calculated to be < 4% (n = 6) for detection of 30 μg L^? 1 Se(IV) and 30 μg L^? 1 Se(VI). The results of the present work confirmed that our developed nano-TiO₂-IC-CD method could be applied for the detection of inorganic selenium species in tap water and drink samples with good recoveries in the range of 82%–108%.     

Kinetic spectrophotometric determination of pravastatin in drug formulations via derivatization with 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl)

A simple and sensitive kinetic spectrophotometric method for the quantitative analysis of pravastatin sodium (PVS) in pure and pharmaceutical formulations has been described. The method is based on the formation of colored product between PVS and 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) in acetone medium at 55 ± 2 °C. The reaction is followed spectrophotometrically by measuring the increase in absorbance at 462 nm as a function of time. The initial rate and fixed time methods were adopted for constructing the calibration curves. The linearity ranges were found to be 15.0–50.0 and 10.0–70.0 μg mL^?1 for initial rate and fixed time methods, respectively. The limits of detection for initial rate and fixed time methods are 0.029 and 0.086 μg mL^?1, respectively. Both methods have been applied successfully for the estimation of PVS in commercial dosage forms with no interference from the excipients. The results are compared with the HPLC pharmacopoeial method.     

An activated carbon with high capacitance from carbonization of a resorcinol–formaldehyde resin

A polymeric activated carbon (PAC) was synthesized from the carbonization of a resorcinol–formaldehyde resin with KOH served as an activation agent. The nitrogen adsorption–desorption at 77 K, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to characterize the prepared PAC. Compared with the commercial activated carbon (Maxsorb: Kansai, Japan), PAC shows superior capacitive performance in terms of specific capacitance, power output and high energy density as electrode materials for supercapacitors. PAC presents a high specific capacitance of 500 F g^?1 in 6 mol l^?1 KOH electrolyte at a current density of 233 mA g^?1 which remained 302 F g^?1 even at a high current density of 4.6 A g^?1. The good electrochemical performance of the PAC was ascribed to well-developed micropores smaller than 1.5 nm, the presence of electrochemically oxygen functional groups and low equivalent series resistance.     

Worm-like mesoporous carbon synthesized from metal–organic coordination polymers for supercapacitors

A green and efficient route has been employed to synthesize a worm-like mesoporous carbon with high specific surface area (2587 m² g^?1) and large pore volume (3.14 cm³ g^?1). Three electrochemical methods have been used to measure its electrochemical performance. Worm-like mesoporous carbon performs the high specific capacitance (344 F g^?1) at constant-current densities of 50 mA g^?1.     

Ion-pairing and reversed phase liquid chromatography for the determination of three different quinolones: Enrofloxacin,lomefloxacin and ofloxacin

Two simple and sensitive high performance liquid chromatographic (HPLC) methods have been developed for the simultaneous determination of three different quinolones: enrofloxacin, lomefloxacin and ofloxacin in their pure and dosage forms, one with reversed phase HPLC and the other with ion-pair HPLC. In reversed phase HPLC, method (A), the mobile phase consists of 2.18% aqueous solution of KH₂PO₄ with pH adjusted to 2.4 ± 0.2 with acetonitrile (80:20; v/v), the mobile phase pumped at flow rate of 1.2 ml min^?1. A Neucleosil C₁₈ column (10 μm, 100 Å), 250 mm length × 4.6 mm diameter was utilized as stationary phase. Detection was affected spectrophotometrically at 294 nm. While in ion-pair HPLC, method (B), the mobile phase was aqueous solution of 0.65% sodium perchlorate and 0.31% ammonium acetate adjusted to pH 2.2 ± 0.2 with orthophosphoric acid: acetonitrile (81:19; v/v), the mobile phase pumped at flow rate of 1.5 ml min^?1. A μ bondapack C₁₈ column (10 μm, 100 Å), 250 mm length × 4.6 mm diameter was utilized as stationary phase. Detection was affected spectrophotometrically at 294 nm. Linearity ranges for enrofloxacin, lomefloxacin and ofloxacin were 4.0–108, 7.0–112 and 8.0–113 μg ml^?1, respectively using method A and 8.0–112, 7.0–112 and 5.0–105 μg ml^?1, respectively applying method B. Minimum detection limits obtained were 0.013, 0.023 and 0.035 μg ml^?1 for enrofloxacin, lomefloxacin and ofloxacin, respectively using method A, and 0.028, 0.023 and 0.011 μg ml^?1 using method B. The proposed methods were further applied to the analysis of enrofloxacin in injection and tablets containing the ofloxacin and lomefloxacin drugs, and the results were satisfied.     

Structural characterization of dodecyltrimethylammonium (DTMA) bromide modified sepiolite and its adsorption isotherm studies

In this study, dodecyltrimethylammonium (DTMA) bromide was used to modify natural sepiolite via an ion exchange reaction to form DTMA-sepiolite. Sepiolite and DTMA-sepiolite were then characterized by using Brunauer–Emmett–Teller (BET), elemental analysis, XRD, FT-IR, thermogravimetric (TG) and zeta potential analysis techniques. The BET surface area of sepiolite significantly decreased from 152.14 m² g^–1 to 88.63 m² g^–1, after the modification, due to the coverage of the pores of sepiolite. DTMA was located onto sepiolite according to the differential thermogravimetric (dTG) peaks of DTMA-sepiolite. XRD results confirmed the interaction between DTMA⁺ cations and sepiolite. FT-IR spectra indicated the existence of DTMA functional groups on sepiolite surface. After the characterization was accomplished, adsorption isotherm studies of naphthalene, which is the first member of the polycyclic aromatic hydrocarbons (PAHs), were carried out. The maximum adsorption capacity of DTMA-sepiolite for naphthalene was determined from Langmuir isotherm equation at pH 6 and 20 °C as 1.88 × 10^–4 mol g^?1 or 24.09 mg g^?1.     

The removal of uranium (VI) from aqueous solutions onto natural sepiolite

The adsorption of uranium (VI) from aqueous solutions onto natural sepiolite has been studied using a batch adsorber. The parameters that affect the uranium (VI) sorption, such as contact time, solution pH, initial uranium(VI) concentration, and temperature, have been investigated and optimized conditions determined. Equilibrium isotherm studies were used to evaluate the maximum sorption capacity of sepiolite and experimental results showed this to be 34.61 mg · g^?1. The experimental results were correlated reasonably well by the Langmuir adsorption isotherm and the isotherm parameters (Q_o and b) were calculated. Thermodynamic parameters (ΔH° = ?126.64 kJ · mol^?1, ΔS° = ?353.84 J · mol^?1 · K^?1, ΔG° = ?21.14 kJ · mol^?1) showed the exothermic heat of adsorption and the feasibility of the process. The results suggested that sepiolite was suitable as sorbent material for recovery and adsorption of uranium (VI) ions from aqueous solutions.     

On-line preconcentration/separation of inorganic arsenic and antimony by poly (aryl ether ketone) containing pendant carboxyl groups prior to microwave plasma atomic spectrometry determinations

A flow injection-column adsorption preconcentration-microwave plasma atomic emission spectrophotometric (FI-column-MP-AES) method is developed for on-line determining trace levels of inorganic arsenic and antimony released from packaging glass containers. The developed methodology involves a micro-column packed with poly (aryl ether ketone) containing pendant carboxyl groups (PEK-L) for adsorption preconcentration procedure before the determination by MP-AES. The main parameters affecting the preconcentration/separation are investigated in details. Under the optimized conditions, the detection limit of the proposed technique is 0.27 μg L^? 1 for As and 0.38 μg L^? 1 for Sb. Precisions, evaluated as repeatability of results (relative standard deviation with n = 7), are 2.8 and 1.8% respectively for As and Sb. The proposed method has been applied to different reference materials and glass bottle packaging samples with satisfactory results.     

Advanced oxidation of aromatic VOCs using a pilot system with electron beam–catalyst coupling

The decomposition of volatile organic compounds (VOCs) using a pilot system of electron beam (EB)–catalyst coupling was investigated. Two aromatic VOCs, toluene (1800 ppmC) and o-xylene (1500 ppmC), were irradiated with a dose range of 0–10 kGy at room temperature. The removal efficiencies for toluene and o-xylene were 92.4% and 94.5%, respectively, under a 10 kGy absorbed dose condition, which were higher than the results of 45.7% and 52.3% when EB-only was used, respectively. The CO₂ selectivity approached 100% for both toluene and o-xylene using the EB-catalyst coupling system, while the concentrations of O₃ formed were 0.02 ppm (toluene) and 0.003 ppm (o-xylene) at 10 kGy. The aerosol concentration was also measured as 43.2 μg/m³ (toluene) and 53.4 μg/m³ (o-xylene) at 10 kGy absorbed dose.     

Thermodynamic analysis of sorption isotherms of chromium(VI) anionic species on reed biomass

A new sorbent material for removing Cr(VI) anionic species from aqueous solutions has been investigated. Adsorption equilibrium and thermodynamics of Cr(VI) anionic species onto reed biomass were studied at different initial concentrations, sorbent concentrations, pH levels, temperatures, and ionic strength. Equilibrium isotherm was analyzed by Langmuir model. The experimental sorption data fit the model very well. The maximum sorption capacity of Cr(VI) onto reed biomass was found to be 33 mg · g^?1. It was noted that the Cr(VI) adsorption by reed biomass decreased with increase in pH. An increase in temperature resulted in a higher Cr(VI) loading per unit weight of the adsorbent. Removal of Cr(VI) by reed biomass seems to be mainly by chemisorption. The change in entropy (ΔS^°) and heat of adsorption (ΔH^°) for Cr(VI) adsorption on reed biomass were estimated as 2205 kJ · kg^?1 · K^?1 and 822 kJ · kg^?1, respectively. The values of isosteric heat of adsorption varied with the surface loading of Cr(VI).     

Adsorption of Cr(VI) using cellulose microsphere-based adsorbent prepared by radiation-induced grafting

Cellulose microsphere (CMS) adsorbent was prepared by radiation-induced grafting of dimethylaminoethyl methacrylate (DMAEMA) onto CMS followed by a protonation process. The FTIR spectra analysis proved that PDMAEMA was grafted successfully onto CMS. The adsorption of Cr(VI) onto the resulting adsorbent was very fast, the equilibrium adsorption could be achieved within 15 min. The adsorption capacity strongly depended on the pH of the solution, which was attributed to the change of both the existed forms of Cr(VI) and the tertiary-ammonium group of PDMAEMA grafted CMS with the pH. A maximum Cr(VI) uptake (ca. 78 mg g^?1) was obtained as the pH was in the range of 3.0–6.0. However, even in strong acid media (pH 1.3), the adsorbents still showed a Cr(VI) uptake of 30 mg g^?1. The adsorption behavior of the resultant absorbent could be described with the Langmuir mode. This adsorbent has potential application for removing heavy metal ion pollutants (e.g. Cr(VI)) from wastewater.     

An understanding of anomalous capacity of nano-sized CoO anode materials for advanced Li-ion battery

Nanostructured transition metal oxides are of great interest as a new generation of anode materials for high energy density lithium-ion batteries. In this work, research has been focused on the nano-sized (grain size ～7 nm) CoO anode material and this material delivers charge capacity of 900 mAh g^?1 that exceeds the theoretical value of 715 mAh g^?1. Possible reason for this unaccounted and unexplained anomalous capacity of the nano-sized CoO material has been suggested by thermogravimetric analysis. A mechanism for this interesting behavior has been systematically evaluated by using X-ray absorption spectroscopy. The anomalous capacity is proposed to be associated with the formation of oxygen-rich CoO material. The results obtained from the nano-sized CoO material have been compared with relatively larger-sized material (grain size ～32 nm).     

Column solid phase extraction and determination of ultra-trace Au,Pd and Pt in environmental and geological samples

A new sorbent based on cysteine modified silica gel (SiG-cys) was prepared and studied for preconcentration and separation of noble metals Au(III), Pd(II), Pt(II), Pt(IV). Its extraction efficiency was examined by batch and column solid phase extraction procedures. Laboratory experiments performed showed that sorbent is characterized with high selectivity, permiting quantitative sorption (93–97%) of noble metals Au, Pd and Pt from acidic media 0.1–2 mol L^? 1 HCl and unsignificant sorption (less than 2%) for common base metals like Cu, Fe, Mn and Zn. The analytes retained on the sorbent are effectively eluted with 0.1 mol L^? 1 thiourea in 0.1 mol L^? 1 HCl and measured by ETAAS or ICP OES under optimal instrumental parameters. The sorbent showed high mechanical and chemical stability and extraction efficiency was not changed after 500 cycles of sorption/desorption. The sorbent was successfully applied in analyticals procedures for preconcentration and determination of Au, Pd and Pt in geological and soil samples. Detection limits (3σ criteria) achieved, depending on the instrumental methods used are: ETAAS (0.005 μg L^? 1 for Au in river and sea water, 0.002 μg g^? 1 for Au in copper ore and copper concentrate); ICP OES (0.03 μg L^? 1 for Pd and 0.06 μg L^? 1 for Pt in river and sea water, 0.006 μg g^? 1 for Pd in copper ore and copper concentrate and 0.002 μg g^? 1 for soluble Pt in soil). The accuracy of the procedures developed was confirmed by added/found method for sea and river water; by the analysis of national certified materials (copper ore and copper concentrate for Au and Pd) and by determination of the sum of soluble Pt(II) + Pt(IV) in spiked soil samples.     

Contribution enthalpic in the interaction of activated carbon with polar and apolar solvents

A method is presented for calculating the contribution that enthalpies make for every component of mixtures of activated carbon–water and activated carbon–hexane to the immersion enthalpy using the concepts that are used in the solution enthalpies. The immersion enthalpies of microporous activated carbon in water and in hexane have values from ?18.97 to ?27.21 and ?25.23 to ?47.89 J g^?1, respectively. From the immersion enthalpies and mass relation of the activated carbon in each of the solvents, the differential enthalpies are calculated for the activated carbon in water, Hw_DIFac, with values between ?15.95 and ?26.81 J g^?1, as are the differential enthalpies for the activated carbon in hexane, ΔHh_DIFac, with values between ?6.86 and ?46.97 J g^?1. For a low mass relation of the mixture components the contributions to the immersion enthalpy of the activated carbon and water differ by 3.20 J g^?1, while the difference between the contributions of the activated carbon and hexane is 19.41 J g^?1.     

Synthesis and application of some novel fluorescent heterocyclic disperse dyestuffs based on phenothiazine on polyester

A series of novel heterocyclic disperse dyestuffs derived from phenothiazine were prepared by standard reactions from phenothiazine as the starting material. Phenothiazine was nitrated and oxidized then reduced to obtain synthesized disperse dyestuffs. The reaction conditions were varied in order to obtain optimal yields for each stage of the preparation to obtain the corresponding derivative and final disperse dyestuffs. All intermediates and disperse dyestuffs were purified and characterized by DSC, FTIR, ¹H NMR, ¹³C NMR, elemental analysis and UV–Visible spectroscopic techniques. The molar extinction coefficients (ε), wavelengths of maximum absorption (λ_max) and solvatochromism effects were studied in solvents as toluene, acetone and N,N-dimethylformamide (DMF). Results represented that the dyestuffs had extinction coefficients of 2011–28189 L mol⁻¹ cm⁻¹, wavelengths of maximum absorption of 448–475 nm in acetone and positive solvatochromism by changing solvent from toluene to DMF. The disperse dyestuffs were applied to locally manufactured polyester fibers and their dyeing properties were investigated. Results showed that the buildup of dyestuffs was acceptable and dyed fibers had very good heat and wash fastness and medium light fastness on polyester fibers.     

Development of a solid phase extraction method for the multielement determination of trace metals in natural waters including sea-water by FI-ICP-MS

An automated solid phase extraction method by flow analysis on-line inductively coupled plasma mass spectrometry (FI-ICP-MS) for the determination of cobalt, chromium, nickel, cadmium, manganese, zinc, copper and lead in sea-water and other natural waters is described. The system is based on retention of the analytes onto a minicolumn packed with a chelating resin, 1,5-bis (2-pyridyl)-3-sulphophenyl methylene thiocarbonohydrazide immobilized on aminopropyl-controlled pore glass, placed in the injection valve of a simple flow manifold. The effects of chemical and flow variables were investigated and selected as a compromise between sensitivity and sampling frequency. So, the sample solutions (adjusted to pH 8.0 ± 0.5) were passed through the column. After washing the column with water, the adsorbed metals were subsequently eluted into the plasma with 4% m/m nitric acid. Detection limits of the trace metals (180 s sample loading time at a sample flow rate of 0.7 mL min^? 1; sampling frequency 8.6 h^? 1) were 0.002 μg L^? 1 for Co, 0.057 μg L^? 1 for Cr, 0.117 μg L^? 1 for Ni, 0.004 μg L^? 1 for Cd, 0.210 μg L^? 1 for Mn, 0.260 μg L^? 1 for Zn, 0.030 μg L^? 1 for Cu and 0.020 μg L^? 1 for Pb, with enrichment factors between 2.2 and 6.8. The accuracy of the proposed method was checked with certified reference materials (CRMs) of sea-water SLEW 3, LGC6016 and CASS-5, river water SLRS-5 and fortified lake water TMDA-54.4. The results from the determination of these metals were in agreement with the certified values and recovery values ranged between 92.2 and 110.6%. The method was applied to the determination of these metal ions in sea-water samples collected in the Málaga Bay in order to realize a pilot study necessary to generate preliminary information on which to base a more detailed pollution study by heavy metals of the Bay.     

Macroporous Co3O4 platelets with excellent rate capability as anodes for lithium ion batteries

This paper reports the microwave-assisted synthesis of Co₃O₄ nanomaterials with different morphologies including nanoparticles, rod-like nanoclusters and macroporous platelets. The new macroporous platelet-like Co₃O₄ morphology was found to be the best suitable for reversible lithium storage properties. It displayed superior cycling performances than nanoparticles and rod-like nanoclusters. More interestingly, excellent high rate capabilities (811 mAh g^?1 at 1780 mA g^?1 and 746 mAh g^?1 at 4450 mA g^?1) were observed for macroporous Co₃O₄ platelet. The good electrochemical performance could be attributed to the unique macroporous platelet structure of Co₃O₄ materials.     

Determination of gallium at trace levels using a spectrofluorimetric method in synthetic U–Ga and Ga–As solutions

A simple, easy to use and selective spectrofluorimetric method for the determination of trace levels of gallium has been developed. A new Schiff base, N-o-vanillidine-2-amino-p-cresol (OVAC) was synthesized and its fluorescence activity with gallium investigated. Based on this chelation reaction, a spectrofluorimetric method has been developed for the determination of gallium in synthetically prepared Ga–U and Ga–As samples buffered at pH 4.0 using acetic acid–sodium acetate. The chelation reaction between Ga(III) and N-o-vanillidine-2-amino-p-cresol was very fast, requiring only 30 min at room temperature to complex completely. The limit of detection (LOD) (3σ) for Ga(III) was 7.17 nM (0.50 μg L^?1), determined from the analysis of 11 different solutions of 20 μg L^?1 Ga(III).