a novel and selective method for the fast determination of trace amounts of zn(ii)ions in water samples has been developed.  the first additional carbonyl and carboxyl functionalized-nano graphene (spfnano graphene). the presence of additional carbonyl and carboxyl groups located at the edge of the sheets makes go sheets strongly hydrophilic, allowing them to readily swell and disperse in water...

A modeling study of benzene and phenyl radical formation was performed for three low-pressure premixed laminar flat flames having an unsaturated C2 or C3 hydrocarbon fuel (acetylene, ethylene, and propene). Predictions using three published detailed elementary-step chemical kinetics mechanisms were tested against molecular beam mass spectrometry (MBMS) species profile data for all three flames....

With more stringent legislation on brominated flame retardants, it is expected that increasing amounts of substitutes would replace polybrominated diphenylethers (PBDEs). Therefore, the development and optimization of analytical methodologies that allow their identification and quantification are of paramount relevance. This work describes the optimization of an analytical procedure to determin...

Two retention time locked methods for the analysis of essential oil compounds are described. The first method is a gas chromatography/flame ionization detector method using a 50 m × 320 μm id × 1.05 μm HP-5 column. The second method is a gas chromatography/mass spectrometry method using a 30 m × 250 μm id × 0.25 μm HP-5MS column. Retention times of approximately 400 essential compounds were mea...

Because cholesterol and its oxide products (COPs) are used as standards during analysis, their stability and autoxidation were assessed under typical storage conditions. Individual toluene solutions of cholesterol; cholesterol5β, 6β-epoxide; cholesta-3,5-dien-7-one; and 5α-cholestane were prepared and aliquots were stored at 23 ± 2°C, 4°C, and -20°C for 7 days. Samples were removed from storage...

A procedure for separation and preconcentration of trace amounts of Zn(II) from aqueous media is proposed. The procedure is based on the adsorption of Zn2+ on octadecyl bonded silica membrane disk modified with N,N’-disalicylidene-1,2-phenylendiamine at pH 7. The retained zinc ions were then stripped from the disk with a minimal amount of 1.5 mol L-1 hydrochloric acid solution as eluent, and de...

The control of Na(+) and Cl(-) uptake from soils, and the partitioning of these ions within plants, is an essential component of salinity tolerance. Genetic variation in the ability of roots to exclude Na(+) and Cl(-) from the transpiration stream flowing to the shoot has been associated with salinity tolerance in many species. The maintenance of a high uptake of K(+) is also essential, so meas...

Flame-retardant polyvinyl alcohol (PVA) membranes with high transparency and flexibility were prepared by mixing an aqueous solution of a phosphorus-containing acrylic acid (AOPA) with PVA. The reaction between AOPA and PVA, the transparency, the crystallinity and the flexibility of the membrane were investigated with Fourier transform infrared spectrometry (FTIR), UV-vis light transmittance, X...

The aim of this work was to determine the heavy metal content of the fruiting bodies of four species of wild edible mushrooms and their respective substrates. The samples were collected from Dambovita County, Romania, at various distances from of a metal smelter, to asses the concentration of Cr, Mn, Fe, Ni, Cu, Zn, Se and Cd in the wild edible mushrooms and their substrate using Energy Dispers...