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...

a chelating resin of polystyrene divinylbenzene resin functionalized by 1-(2-pyridylazo) 2- naphtol (psdvb-pan) has been synthesized and its sorption properties have been investigated for preconcentration and determination of cadmium at μg/l level by flame atomic absorption spectrometry. the procedure is based on the sorption of cd(ii) ions on a minicolumn of synthesized chelating resin. the re...

This paper describes four recent applications of analytical pyrolysis in environmental science and engineering. In all applications, samples were analyzed in order to provide information about the origin of organic matter or changes to an organic matrix. In the first application, pyrolysis-gas chromatography/mass spectrometry (GC/MS) and pyrolysis-GC/flame ionization detection (FID) were used t...

Comprehensive two-dimensional gas chromatography (GCxGC) offers an interesting tool for profiling bacterial fatty acids. Flow modulated GCxGC using a commercially available system was evaluated, different parameters such as column flows and modulation time were optimized. The method was tested on bacterial fatty acid methyl esters (BAMEs) from Stenotrophomonas maltophilia LMG 958T by using para...