Determination of europium(III) in environmental samples using a flow injection analysis system with on-line preconcentration and spectrophotometric detection

A simple and accurate flow injection analysis system coupled with spectrophotometric detector was developed for preconcentration and determination of europium(III) in aqueous samples. The developed flow system includes a europium preconcentration step in a column packed with Amberlite XAD-4 resin impregnated with nalidixic acid at pH 7.0. The europium complex was desorbed from the resin by 0.1 mol L^?1 HCl and mixed with arsenazo-III solution (0.05 % solution in 0.1 mol L^?1 HCl) and taken to the flow through cell of spectrophotometer where its absorbance was measured at 661 nm. The optimum preconcentration system, chemical and FIA variables were investigated. The preconcentration factors obtained were 115 and 500, detection limits of 0.43 and 0.1 μg L^?1, sample throughputs of 40 and 10 were obtained for preconcentration time of 60 and 300 s respectively. The proposed system showed good precision and accuracy with relative standard deviation of 1.5 %. The method has been applied to the determination of europium(III) in real water samples and certified reference material IAEA-SL-1 (Lake sediment).     

Adjuvants that Empower the Action of Photodynamic Therapy

Compounds have been devised whose supportive actions make them important adjuvants in the priming of photosensitization to selectively target cancer cells. Here, we highlight the paper by Maytin and Hasan in this issue of Photochemistry & Photobiology, which describes adjuvants methotrexate, 5-fluorouracil, vitamin D and its analogs leading to improved photodynamic therapy outcome. These small molecule adjuvants act by different mechanisms to enhance the cytotoxicity in tumor cells and the therapeutic effect in cancers. These findings add to the list of strategies for enhancement of photodynamic therapy.     

Anti-glycating and anti-oxidant compounds from traditionally used anti-diabetic plant Geigeria alata(DC) Oliv. & Hiern.

Abstract

A new sesquiterpene lactone geigerianoloide (1) and four known flavonoids axillarin (2), quercetin (3), 3-methoxy-5,7,3',4'-tetrahydroxy-flavone (4) and hispidulin (5) were isolated from Geigeria alata (DC) Oliv. & Hiern. (Asteraceae). Structures were deduced using ¹H- and ¹³C- NMR spectroscopy, mass spectrometry, while the structure of compound 1 was also deduced using X-ray crystallography technique.

Geigeria alata is traditionally used for diabetes, therefore compounds were tested for anti-glycation activity, in which compounds 2 and 3 showed potent activities (IC₅₀ values of 246.97?±?0.83 and 262.37?±?0.22 µM, respectively) compared to IC₅₀ value 294.50?±?1.5 µM of rutin. Moreover, compound 4 exhibited a comparable activity to rutin (IC₅₀?=?293.28?±?1.34 µM). Compound 5 showed a weak activity.

Compounds 2, 3, and 4 exhibited potent DPPH radical scavenging activity (IC₅₀?=?0.1?±?0.00, 0.13?±?0.00 and 0.15?±?0.01 µM, respectively). Compounds 2, 3, and 4 demonstrated significant superoxide anion scavenging activity with IC₅₀ values of 0.14?±?0.001, 0.17?±?0.00, and 0.11?±?0.006 µM, respectively.     

Biofortification—A Frontier Novel Approach to Enrich Micronutrients in Field Crops to Encounter the Nutritional Security

Globally, many developing countries are facing silent epidemics of nutritional deficiencies in human beings and animals. The lack of diversity in diet, i.e., cereal-based crops deficient in mineral nutrients is an additional threat to nutritional quality. The present review accounts for the significance of biofortification as a process to enhance the productivity of crops and also an agricultural solution to address the issues of nutritional security. In this endeavor, different innovative and specific biofortification approaches have been discussed for nutrient enrichment of field crops including cereals, pulses, oilseeds and fodder crops. The agronomic approach increases the micronutrient density in crops with soil and foliar application of fertilizers including amendments. The biofortification through conventional breeding approach includes the selection of efficient genotypes, practicing crossing of plants with desirable nutritional traits without sacrificing agricultural and economic productivity. However, the transgenic/biotechnological approach involves the synthesis of transgenes for micronutrient re-translocation between tissues to enhance their bioavailability. Soil microorganisms enhance nutrient content in the rhizosphere through diverse mechanisms such as synthesis, mobilization, transformations and siderophore production which accumulate more minerals in plants. Different sources of micronutrients viz. mineral solutions, chelates and nanoparticles play a pivotal role in the process of biofortification as it regulates the absorption rates and mechanisms in plants. Apart from the quality parameters, biofortification also improved the crop yield to alleviate hidden hunger thus proving to be a sustainable and cost-effective approach. Thus, this review article conveys a message for researchers about the adequate potential of biofortification to increase crop productivity and nourish the crop with additional nutrient content to provide food security and nutritional quality to humans and livestock.     

Determination of lithium isotopic composition by thermal ionization mass spectrometry in seawater

The isotopic composition of lithium in seawater has been determined by thermal ionization mass spectrometry (TIMS) based on the use of lithium hydroxide as the ion source. Isotopic measurements in a reference material supplied by IAEA (L-SVEC Li₂CO₃) were made to check the reproducibility of the method and ⁶Li indicates mobilization of light isotope of lithium form the sediment.     

Linear and nonlinear fluctuations of electron-temperature-gradient driven mode and electron acoustic mode in a two-electron temperature nonthermal magnetized plasma

Nonlinear vortical structures and soliton formation are investigated for electron temperature gradient instability in a two-electron temperature non-Maxwellian magnetoplasma. The inhomogeneity in magnetic field is also considered. A new set of nonlinear equations, using transport equations of Braginskii”s model, are formulated to study the nonlinear structures. A modified linear dispersion relation of coupled electron temperature gradient (ETG) mode and electron acoustic wave is derived. The ETG instability is found to increase with increase in η_ec value that increases with sharp density gradients. The results are applied to auroral region of earth's magnetosphere and the calculated values of the nonlinear electric field of fast solitary waves are found to be in agreement with the Viking satellite observations.     

Online thorium determination after preconcentration in a minicolumn having XAD-4 resin impregnated with N-benzoylphenylhydroxylamine by FI-spectrophotometry

A very sensitive and selective flow injection on-line determination method of thorium (IV) after preconcentration in a minicolumn having XAD-4 resin impregnated with N-benzoylphenylhydroxylamine is described. Thorium (IV) was selectively adsorbed from aqueous solution of pH 4.5 in a minicolumn at a flow rate of 13.6 mL min^?1, eluted with 3.6 mol dm^?3 HCl (5.6 mL min^?1), mixed with arsenazo-III (0.05% in 3.6 mol dm^?3 HCl stabilized with 1% Triton X-100, 5.6 mL min^?1) at confluence point and taken to the flow through cell of spectrophotometer where its absorbance was measured at 660 nm. Peak height was used for data analyses. The preconcentration factors obtained were 32 and 162, detection limits of 0.76 and 0.150 ??g L^?1, sample throughputs of 40 and 11 h^?1 for preconcentration times of 60 and 300 s, respectively. The tolerance levels for Zr(IV) and U(VI) metal ions is increased to 50-folds higher concentration to Th(IV). The proposed method was applied on different spiked tap water, sea water and biological sample and good recovery was obtained. The method was also applied on certified reference material IAEA-SL1 (Lake Sediment) for the determination of thorium and the results were in good agreement with the reported value.     

Soil Thin-Layer Chromatography of Heavy Metal Cations with Surfactant-Modified Mobile Phases: Mutual Separation of Zinc(II), Cadmium(II), and Mercury(II)

JPC – Journal of Planar Chromatography – Modern TLC - Thin-layer chromatography of ten metal ions has been performed on pure soil layers; the mobile phases were aqueous organic and...