1,721,172 research outputs found
ANALYSIS OF POLYCHLOROBIPHENYLS (PCBS) IN CONTAMINATED SOIL SAMPLES BY SUPERCRITICAL FLUID EXTRACTION SUPERCRITICAL FLUID CHROMATOGRAPHY COUPLED WITH FT-IR SPECTROMETRY
No full textA supercritical fluid extraction-supercritical fluid chromatography system coupled off-line with FT-IR spectrometry is described. The effects of pressure, temperature and time on the efficiency of the extraction of PCBs in certified and spiked soil samples were studied. A typical recovery of 75 % with a relative standard deviation of 7 % was obtained. The identity of chromatographic peaks was found by comparing their infrared spectra with reference spectra obtained from standard Aroclor solutions
Rivelazione e determinazione indivuale di cromo(VI) e cromo(III), insieme a rame, piombo, nichel e zinco - in acqua potabile a livello di ppb.
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Individual detection and determination of Cr(VI) and Cr (III) - together with Cu, Pb, Cd, Ni and Zn - in tap water at ppb level.
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Polychlorobiphenyls (PCBs) in the environment: analytical procedures and data evaluation
No full textPolychlorobiphenyls (PCBs) have been produced since 1930 and exploited for a variety of purposes, including use in transformers, capacitors, paints, pesticides, and many other highly developed industrial activities. The high chemical and physical stability and the lipophilic characteristics of these compounds are responsible for their long-term persistence in the environment and for their ability to bioaccumulate. These reasons, along with the discovery of the widespread environmental occurrence of these pollutants and the possible connection of their presence to carcinogenesis, has led in the past few years to PCBs being included in the list of priority pollutants, thus making their monitoring in the environment and studies of their toxic effects on living organisms of prime importance. This paper describes analytical methodologies, interference elimination procedures, and quantitation criteria for PCB analysis in several different environmental matrices. The individual determination of non-ortho chlorinated congeners, whose toxicity factors are comparable with those of tetrachlorodibenzo-p-dioxins, and the application of supercritical fluid extraction and chromatography for their separation, and Fourier-transform infrared spectrometry for their identification are also discussed
Interfacciamento di tecniche cromatografiche diverse con la spettrometria FT-IR e relative applicazioni
No full textTecniche voltammetriche moderne: la misura del segnale ed il calcolo della concentrazione
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