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Application of SPE for selective fractionation of essential oils constituents from plant materials

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Szewczyk J., Dybowski M. P., Dawidowicz A. L.
Annales Universitatis Mariae Curie-Skłodowska, sectio AA – Chemia
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2015
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vol. 70
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issue 2
EN
Solid-phase extraction (SPE) is simple and inexpensive sample preparation procedure which can be applied for the isolation/fractionation of essential oil compounds from wide variety of samples, such as foodstuffs, biological and environmental. Due to the complex nature of the examined matrices and frequently low concentration level of target components, analytical procedures require the use of initial sample preparation stage. The paper shows the possibility of essential oil components fractionation from different plant materials using SPE method. The results presented in this paper shows that the proposed SPE procedure allows for easy and total fractionation of essential oil constituents (especially low-molecular oxygen compounds) from the sample matrix.
2
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Single-walled carbon nanotubes fractionation via electrophoresis

100%
Scheibe B., Lukaszczuk P., Rümmeli M., Kalenczuk R., Borowiak-Palen E.
Polish Journal of Chemical Technology
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2011
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vol. 13
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issue 3
1-4
EN
This work presents the influence of the sonication time on the efficiency of the metallic/semiconducting (M/S) fractionation of diazonium salt functionalized single-walled carbon nanotubes (SWCNTs) via free solution electrophoresis (FSE) method. The SWCNTs synthesized via laser ablation were purified from amorphous carbon and catalyst particles through high vacuum annealing and subsequent refluxing processes in aqua regia solutions, respectively. The purified material was divided into two batches. The SWCNTs samples were dispersed in 1% SDS solution in ultrasound bath for 2 and 12 hours. Both dispersed SWCNTs samples were functionalized with p-aminobenzoic acid diazonium salt and fractionated via free solution electrophoresis method. Afterwards, the fractionated samples were recovered, purified from surfactant/functionalities by annealing and investigated via UV-Vis-NIR optical absorption spectroscopy (OAS). The efficiency of the fractionation process was estimated through the comparison of the van Hove singularities (vHS) presented in the obtained fractions to the starting SWCNTs.
3
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Speciation of heavy metals during co-composting of livestock manure

88%
Gul S., Naz A., Fareed I., Khan A., Irshad M.
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EN
Heavy metals determination in manures provides beneficial information to predict the availability and the potential contamination of environment. Therefore, a study was carried out to investigate heavy metals changes in livestock manure during a co-composting process. The metals were stepwise fractionated into exchangeable, adsorbed, organically bound, carbonate precipitated and residual forms by extracting with 0.5M KNO3, de-ionized water, 0.5M NaOH, 0.05M Na2EDTA and 4M HNO3, respectively. During the extraction process, the amount of metals remained highly dependent on an extraction method and stage of manure composting. Extractions released heavy metals contents in the final composted manure as Zn > Cu > Pb > Cr > Ni > Cd. Irrespective of the days of composting, extracting agents differed in the order HNO3 > Na2EDTA > NaOH > KNO3 > H2O for all heavy metals. Higher concentrations of heavy metals were observed during the early stages of composting. Conversely, there was a progressive increase in the concentrations of K, Ca and Mg during composting of manure. Total C in the manure reduced with composting days.
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