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61.
Epiphytic lichens have long been considered to be reliable bioindicators of air pollution. In the present study only one lichen species, Hypogymnia physodes (L.) Nyl., was chosen; this species is very often used for biomonitoring in Europe. Total mercury and methylmercury were determined in lichens taken from various polluted and unpolluted locations in Slovenia, including a mercury mining area around Idrija. Additionally, total gaseous mercury in air was also determined at several sampling points. 相似文献
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Sample preparation in analysis of pharmaceuticals 总被引:1,自引:0,他引:1
Dragana Mutavdi Pavlovi Sandra Babi Alka J.M. Horvat Marija Katelan-Macan 《Trends in analytical chemistry : TRAC》2007,26(11):1062-1075
Sample preparation is a very important and essential step in environmental analysis. This article presents an overview of extraction methods for environmental samples, focusing especially on pharmaceuticals as there is great concern about them as pollutants. 相似文献
65.
Novel Inorganic Ring Systems. 34. Derivatives of the Cyclo-1-thiaIV- and of the Cyclo-1-thia VI-3,4-disila-2,5-diazane Variations of fivemembered “hetero” cyclosilazanes of the type Si2N2El could be enlarged to the systems with El = SO and SO2. They are obtained by the formation principles 4 + 1 and 2 + 3 respectively, according to the equation (1), (4) and (5). The prepared compound are described in their properties and confirmed in their structure (Tables 1–2). 相似文献
66.
The synthetically interesting processes available for indolization reactions are discussed and illustrated in tabular form and particular emphasis is placed on the more recent methods. 相似文献
67.
Ti7Cl16 and Ti7Br16 and Further Investigations with Titanium Halides. Al2X6 as a Complex Forming Agent TiCl3,s can be transported with Al2Cl6 via TiAlCl6,g in a temperature gradient. The equilibrium of this reaction was studied by mass spectroscopy. There is no indication of the existence of a TiAl2Cl9 molecule as assumed in the literature. β-TiBr3 was prepared from the elements in the presence of the transporting agent Al2Br6,g. The transport of TiCl2 with Al2Cl6,g involves, as an important step, the disproportionation which is favoured by the reaction of Ti with the glass wall. If the disproportionation is made impossible by addition of Ti the novel compound Ti7Cl16 is obtained. Independent of Ti7Cl16, a phase TiCl(2 + x) with a broad range of homogeneity exists. The compound Ti7Br16, being isostructural with Ti7Cl16, was also prepared. Results of magnetic measurements and observations on the thermal decomposition of the compounds are reported. 相似文献
68.
A simple modification of the West?? extraction procedure for methylmercury and its determination by gas chromatography (GC) is presented. The cysteine clean-up step has been modified, with use of cysteine-impregnated paper instead of cysteine solution. Methylmercury bromide is extracted from the sample into toluene and is selectively adsorbed on the cysteine paper. Interfering compounds are washed from the paper with toluene. The isolated methylmercury is set free with sulphuric acid containing bromide, extracted into benzene and determined by GC. The modification of the extraction procedure results in good recovery and reproducibility for various biological and environmental samples, good sensitivity with a detection limit of 0.1 ng/g, avoidance of difficulties arising from emulsion formation, cleaner chromatograms, and faster analysis. It is particularly suitable for determination of low levels of MeHg. 相似文献
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Frank C Sottmann T Stubenrauch C Allgaier J Strey R 《Langmuir : the ACS journal of surfaces and colloids》2005,21(20):9058-9067
In ternary water-oil-nonionic alkyl polyglycol ether (C(i)E(j)) microemulsions, an increase in efficiency is always accompanied by the formation of a lamellar (L(alpha)) phase. The addition of an amphiphilic block copolymer to the ternary base system increases the efficiency of the microemulsion drastically while suppressing--at least partly--the formation of the L(alpha) phase. However, amphiphilic block copolymers can be used not only to suppress the formation of lyotropic liquid crystals but also for the opposite effect, namely, to induce their formation. To understand to what extent the increase in efficiency is accompanied by the formation of lyotropic liquid crystals, we studied phase diagrams of water-n-alkane-n-alkyl polyglycol ethers (C(i)E(j))-PEPX-PEOY at a constant volume fraction of oil in the water/oil mixture. Using polymers of the poly(ethylene propylene)-copoly(ethylene oxide) type, with M(PEP) = X kg mol(-1) and M(PEO) = Y kg mol(-1), we determined phase diagrams as a function of the polymer concentration, size, and symmetry. Moreover, the influence of a particular polymer mixture was studied, which turned out to be the best system if both a high efficiency and a low tendency to form an L(alpha) phase are needed. 相似文献