Elisaveta Mladenova

Dr. Elisaveta Mladenova

Sofia University "St. Kliment Ohridski" Faculty of Chemistry and Pharmacy
orcid

Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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26 June 2012 in Journal of Separation Science
Verified
Journal Article
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EMElisaveta Mladenova
Elisaveta Mladenova
IKIrina B. Karadjova
Irina B. Karadjova
DTDimiter L. Tsalev
Dimiter L. Tsalev

1 March 2012 in Microchemical Journal
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Journal Article
Closed access
EMElisaveta Mladenova
Elisaveta Mladenova
IDIvanka Dakova
Ivanka Dakova
IKIrina B. Karadjova
Irina B. Karadjova
MKMethody Karadjov
Methody Karadjov

25 May 2011 in Environmental Science and Pollution Research
Verified
Journal Article
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EMElisaveta Mladenova
Elisaveta Mladenova
IDIvanka Dakova
Ivanka Dakova
IKIrina B. Karadjova
Irina B. Karadjova

28 November 2021 in Molecules
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Journal Article
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TVTsvetomil Voyslavov
Tsvetomil Voyslavov
EMElisaveta Mladenova
Elisaveta Mladenova
Ralitsa BalkanskaRalitsa Balkanska
Ralitsa Balkanska
A new approach for the botanical origin determination of monofloral bee honey is developed. The methodology combines mineral content and physicochemical parameters determination with intelligent statistics such as self-organizing maps (SOMs). A total of 62 monofloral bee honey samples were analysed, including 31 linden, 14 rapeseed, 13 sunflower, and 4 acacia. All of them were harvested in 2018 and 2019 from trusted beekeepers, after confirming their botanical origin, using melissopalynological analysis. Nine physicochemical parameters were determined, including colour, water content, pH, electrical conductivity, hydroxymethylfurfural content, diastase activity, specific optical rotation, invertase activity, and proline. The content of thirty chemical elements (Ag, Al, As, B, Ba, Bi, Ca, Cd, Co, Cr, Cs, Cu, Fe, Ga, In, K, Li, Mg, Mn, Na, Ni, P, Pb, Rb, S, Se, Sr, Te, V, and Zn) was measured using ICP-OES, ICP-MS, and FAAS as instrumental techniques. The visualisation of the SOMs shows an excellent separation of honey samples in five well-defined clusters—linden, rapeseed, acacia, sunflower, and polyfloral honey—using the following set of 16 descriptors: diastase activity, hydroxymethylfurfural content, invertase activity, pH, specific optical rotation, water content, Al, B, Cr, Cs, K, Na, Ni, Rb, V, and Zn.

29 May 2012 in Open Chemistry
Verified
Journal Article
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EMElisaveta Mladenova
Elisaveta Mladenova
IDIvanka G. Dakova
Ivanka G. Dakova
DTDimiter L. Tsalev
Dimiter L. Tsalev
IKIrina B. Karadjova
Irina B. Karadjova
A sorbent L-cysteine grafted silica gel has been evaluated for separation and enrichment of dissolved inorganic i-Hg(II) and methylmercury CH3Hg(I) from surface waters at sub-µg L−1 concentrations. Chemical parameters for mercury species enrichment and separation have been optimized. Analytical schemes for the determination of Hg species, using selective column solid phase extraction (SPE) with continuous flow chemical vapor generation atomic absorption spectrometry (CF-CVG-AAS) or inductively coupled plasma-mass spectrometry (ICP-MS) were developed. Possibilities for on-site SPE enrichment were demonstrated as well. The limits of quantification were 1.5 and 5 ng L−1 for dissolved i-Hg(II) and CH3Hg(I) by CF-CVG-AAS and 1 and 2.5 ng L−1 by ICP-MS with relative standard deviations between 7–12% and 7–14%, respectively. The chemically modified SPE sorbent has demonstrated high regeneration ability, chemical and mechanical stability, acceptable capacity and good enrichment factors. Results for total dissolved mercury were in reasonable agreement with those from independent analyses by direct ICP-MS determinations for river waters and for estuarine water certified reference material.

1 December 2017 in Journal of Apicultural Science
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Journal Article
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RBRalitsa Balkanska
Ralitsa Balkanska
EMElisaveta Mladenova
Elisaveta Mladenova
IKIrina Karadjova
Irina Karadjova
The objective of the present study was to investigate selected trace and mineral elements in Royal Jelly (RJ) from Bulgaria. A total of 30 RJ samples were included in the study. The analytical procedure consisted of the microwave digestion of the RJ samples with nitric acid followed by instrumental measurement. Concentrations of Al, Ba, Ca, Cr, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn were determined using inductively coupled plasma optical emission spectroscopy (ICP-OES), while As, Cd, Co, Ni and Pb were determined by electrothermal atomic absorption spectrometry (ETAAS). Our results showed that elements K, Mg, Ca represented 96% from the total mineral content of the RJ samples from Bulgaria, while the most abundant trace element was Na, followed by Zn. The elements Ba, Cr, Cu, Fe, Mn and Sr were found in trace concentration levels and elements As, Pb, Cd, Co and Ni in microconcentration levels. Selected mineral and trace elements were found in relatively constant concentration levels in all of the analyzed RJ samples. It was concluded that chemical element content did not depend on geographical origin and was under homeostatic adjustment in RJs.