Nikolaya Velitchkova | Bulgarian Academy of Sciences (original) (raw)

Papers by Nikolaya Velitchkova

Research paper thumbnail of Application of high-resolution 40.68 MHz radial-viewing inductively coupled plasma optical emission spectrometry in rhenium determination

Geologica Balcanica, 2017

The possibilities of 40.68 MHz radial-viewing inductively coupled plasma optical emission spectro... more The possibilities of 40.68 MHz radial-viewing inductively coupled plasma optical emission spectrometry equipped with a high-resolution spectrometer (spectral bandwidth = 5 pm) (HR-ICP-OES) were studied in the determination of rhenium in molybdenum and copper concentrates. By using equipment with a high spectral resolution, a hyperfine structure (HFS) of the most prominent lines of rhenium (i.e., Re II 197.248 nm, Re II 221.426 nm and Re II 227.525 nm) were registered. The HFS components, under high-resolution conditions, were used as separate prominent lines in order to circumvent spectral interferences in the presence of complex matrix containing Mo, Al, Ti, Fe, Mg, Ca and Cu. The Q-concept was applied for quantification of the spectral interferences and optimum line selection. Microwave acid digestion method was used as a sample dissolution procedure. The feasibility, accuracy and precision of the analytical results were experimentally demonstrated by certified reference materials...

Research paper thumbnail of Retention of Cs in Boom Clay: Comparison of data from batch sorption tests and diffusion experiments on intact clay cores

Physics and Chemistry of the Earth, Parts A/B/C, 2008

... 2) compares well with previous published data ([Baeyens, 1982], [Bradbury and Baeyens, 2000] ... more ... 2) compares well with previous published data ([Baeyens, 1982], [Bradbury and Baeyens, 2000] and [De Preter et al., 1991]) and can be approximated by a Freundlich isotherm (C ads = K f × View the MathML source , with K f the distribution coefficient in case of a Freundlich ...

Research paper thumbnail of Heavy metal and metalloid mobilisation and rates of contamination of water, soil and bottom sediments in the Chiprovtsi mining district, Northwestern Bulgaria

<jats:p>Geochemical studies of seasonally collected mine, stream and drinking waters, botto... more <jats:p>Geochemical studies of seasonally collected mine, stream and drinking waters, bottom sediments (mine and stream) and soil samples from all mining sections were carried out in order to assess the rates of pollution in the immediate proximity to underground mining facilities and related waste rock dumps. The determined concentrations of studied elements in water (As, Pb, Cu, Zn and Sb) show spatial distribution corresponding to ore mineralisation in different sections. Arsenic concentrations show gradual decrease in west-east direction, whereas Pb concentrations peak in the central and eastern sections. Arsenic and, to a lesser extent, Pb proved to be major pollutants in mine and surface waters, as well as in bottom sediments and soils. Detailed geochemical study of soils revealed strong spatial relation with host rocks and ore mineralogy. Comparisons with state guidelines for harmful elements revealed that alluvial and meadow soils in close proximity to waste dumps contain As, Pb, Cu, Zn and Cd above maximum permissible levels. It was also found that, compared to other Bulgarian and world alluvial (fluvisol) soils and the upper continental crust, the soils in Chiprovtsi mining district are enriched in Te, Re, W, Pd, Au, Ag, Mo, Ti, Mn, Co, Se, Sb, Bi and Cs. Since the processes of weathering and oxidation of mine waste remaining in the area continue naturally, the pollution with As and Pb will presumably carry on with decreasing effect.</jats:p>

Research paper thumbnail of Determination of arsenic, mercury, selenium, thallium, tin and bismuth in environmental materials by inductively coupled plasma emission spectrometry

Spectrochimica Acta Part B: Atomic Spectroscopy, 2004

Research paper thumbnail of Heavy Metal Mobility and Speciation in Coal Ash Reclaimed Hydrophobic Mine Soils

World Academy of Science, Engineering and Technology, International Journal of Agricultural and Biosystems Engineering, 2018

Research paper thumbnail of Spectral interferences in the determination of rhenium in molybdenum and copper concentrates by inductively coupled plasma optical emission spectrometry (ICP-OES)

Spectrochimica Acta Part B: Atomic Spectroscopy, 2016

Research paper thumbnail of Heavy metal mobility in soils under the application of sewage sludge

Bulgarian Journal of Agricultural Science

One of the main issues relating to sewage sludge (SS ) disposal is the introduction of heavy meta... more One of the main issues relating to sewage sludge (SS ) disposal is the introduction of heavy metals and organic pollutants. The aim of this research work was to assess the mobility of heavy metals via measurement of the soluble and easily exchangeable metals in soils on which sewage sludge had been deposited 10 years before analysis and clarify patterns and relationships between heavy metals in the amended soils as opposed to un-amended control soils. There are few studies on the leaching potential of heavy metals in sludge-amended soils through measurement of the soluble and easily exchangeable metal forms. Mobile heavy metals (soluble + easily exchangeable Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were measured via extraction with 0.05 M Ca(NO 3)2. We observed: (i) elevated Cd, Cr, Zn and Cu concentrations in the sludge treated soils; (ii) no effect of sludge application was found, as far as Pb, Mn, Fe, Ni and Co mobilities are concerned; (iii) the statistical analysis showed that sl...

Research paper thumbnail of Dynamics and evolution of heavy metal water pollution in the Plovdiv region (Bulgaria)

Research paper thumbnail of Determination of Y, Zr, Nb, Hf, Ta and Th in geological materials by inductively coupled plasma emission spectrometry

This paper deals with spectral interferences in radial - viewing Inductively Coupled Plasma Atomi... more This paper deals with spectral interferences in radial - viewing Inductively Coupled Plasma Atomic Emission Spectrometry (lCP-AES) in the determination of Y, Zr, Nb, Hf, Ta and Th in geological materials.The spectral interferences in the presence of Al, Ca, Mg, Fe, Ti, Mn, Na, K and P as maffix constituents around the prominent lines of analytes were studied. Q -values for line interference [QIJ (a)] and Q-values for wing background interference [QWJ(Δλa)] were obtained for quantification of spectral interferencesin the presence of multicomponent eological matrix. The prominent lines free or negligibly influenced by multicomponent line interference were selected for analyte determination. Q -values were used for optimum line selection and for calculation of the true detection limits. Comparison of the magnitude of the spectral interferences and the detection limits in the presence of geological samples by using ICP-AES equipmen with different ICP frequencies and the spectrometer ty...

Research paper thumbnail of Posibilities of Inductively Coupled Plasma Optical Emmission Spectrometry (Icp-Oes) in the Determination of Rare and Trace Elements

The economic and geological importance of Zr, Nb, Hf, Ta, Th, Pt, Pd, Rh and rare earth elements ... more The economic and geological importance of Zr, Nb, Hf, Ta, Th, Pt, Pd, Rh and rare earth elements has led to the development of analytical methods, which have to ensure their accurate quantification in different type of samples. Radial viewing 40.68 MHz inductively coupled plasma optical emission spectrometry (ICP-OES) and Q - concept for the quantification of spectral interference were used in the determination of these elements in materials with variable matrix constituents. The accuracy of the results was experimentally demonstrated by using certified reference materials. Improvement of the detection limits was achieved by optimization of the operating conditions. Keywords: ICP-OES, geological samples, Eu2O3, Zr, Nb, Hf, Ta, Th, Pt, Pd, Rh, Y, Sc, rare earth elements;

Research paper thumbnail of Determination of As, Zn, Pt, B, Hg, Cd, Tl and U in environmental materials by high resolution radial viewing 40.68 MHz inductively coupled plasma optical emission spectrometry (ICP - OES)

Bulgarian Chemical Communications

The possibilities and limitations of high resolution radial viewing 40.68 MHz inductively coupled... more The possibilities and limitations of high resolution radial viewing 40.68 MHz inductively coupled plasma optical emission spectrometry (ICP - OES) were shown in the determination of As, Zn, Pt, B, Hg, Cd, Tl and U in environmental materials. Improvement of the detection limits was achieved by optimization of the operating conditions. The lowest detection limits were obtained under robust conditions (excitation temperature ≈ 7200 K in pure solvent and in presence of Al, Ca, Fe, Mg and Ti as a complex environmental matrix). The detection limits in the determination of As, Zn, B, Hg, Cd, Tl and U satisfy the requirements for maximum permissible concentrations in soils and drinking waters. In the determination of Pt in road dust an improvement of the detection limit was achieved by the development of a new column method with 2-mercaptobenzimidazole immobilized on activated carbon for separation of the matrix elements Al, Ca, Fe, Mg and Ti and pre-concentration of platinum.

Research paper thumbnail of Possibilities of High Resolution Inductively Coupled Plasma Optical Emission Spectrometry in the Determination of Trace Elements in Environmental Materials

Journal of Spectroscopy, 2013

This paper presents new quantitative data for the spectral interferences obtained by high resolut... more This paper presents new quantitative data for the spectral interferences obtained by high resolution 40.68 MHz radial viewing inductively coupled plasma optical emission spectrometry (HR-ICP-OES) in the determination of Zn, Cd, Sb, Cu, Mn, Pb, Sn, Cr, U, and Ba in environmental materials in the presence of a complex matrix, containing Al, Ca, Fe, Mg, and Ti. The-concept for quantification of spectral interferences was used. The optimum line selection for trace analysis of a variety of multicomponent matrices requires the choice of prominent lines, which are free or negligibly influenced by line interference problems. The versatility of-concept as basic methodology was experimentally demonstrated in the determination of trace of elements in soil and drinking water. The detection limits are lower in comparison with corresponding threshold concentration levels for soil and drinking water in accordance with environmental regulations. This paper shows the possibilities of present day ICP-OES equipment in the direct determination of trace elements (without preconcentration of impurities) in environmental samples.

Research paper thumbnail of Problems, possibilities and limitations of inductively coupled plasma atomic emission spectrometry in the determination of platinum, palladium and rhodium in samples with different matrix composition

Spectrochimica Acta Part B: Atomic Spectroscopy, 2010

The economic and geological importance of platinum group of elements has led to the development o... more The economic and geological importance of platinum group of elements has led to the development of analytical methods to quantify them in different types of samples. In the present paper the quantitative information for spectral interference in radial viewing 40.68 MHz inductively coupled plasma atomic emission spectrometry in the determination of Pt, Pd and Rh in the presence of complex matrix, containing Al, Ca, Fe, Mg, Mn, P and Ti as matrix constituents was obtained. The database was used for optimum line selections. By using the selected analysis lines the following detection limits in ng g − 1 were obtained: Pt 1700, Pd-1440, Rh-900. The reached detection limits determine the possibilities and limitation of the direct ICP-AES method in the determination of Pt, Pd and Rh in geological and environmental materials. The database for spectral interferences in the presence of aluminum can be used for the determination of platinum group of elements in car catalysts. The accuracy of the analytical results was experimentally demonstrated by two certified reference materials that were analyzed: SARM 7, Pt ore and recycled auto-catalyst certified reference material SRM 2556.

Research paper thumbnail of Inductively Coupled Plasma-Atomic Emission Spectroscopy: Two Laboratory Activities for the Undergraduate Instrumental Analysis Course

Journal of Chemical Education, 2003

Research paper thumbnail of Heavy metal and metalloid concentrationdynamics in mine and surface waters in the vicinity of Chiprovtsi and Martinovo, mines, northwestern Bulgaria

Chiprovtsi silver-lead and Martinovo iron mines represent the biggest mining area in Northwestern... more Chiprovtsi silver-lead and Martinovo iron mines represent the biggest mining area in Northwestern Bulgaria, which was operated till 1999. Their long-lived operation leads to proved pollution of the environment in the vicinity of the mines, especially water and soil. Seasonal monitoring of heavy metal (Cu, Zn, Cd and Pb) and metalloid (As and Sb) concentrations in mine, surface (river) and drinking waters was carried out during May and August 2006 to determine the level of contamination of the Chiprovska Ogosta river basin resulting from the long-lived mining activity and whether these abandoned mines continue to be potential source for water pollution. This study proves significant As concentrations in mine (up to 170 μg/l) and surface waters (between 50 and 621 μg/l). The presence of other heavy metals, such as Cu, Cd, Zn and Pb, and metalloid-Sb is also recorded. Among them, Pb was found in considerable concentrationsup to 1456 pg/l during May 2006 sampling exhibiting great concentration variability between dry and wet sampling seasons. Sb is also determined in mine waters (up to 25 pg/l), but not exists in surface and drinking waters. Drinking waters are proved to be free of heavy metals and metalloids.

Research paper thumbnail of Application of inductively-coupled plasma atomic emission spectrometry with an internal reference to the determination of sulfate and calcium in waters and brines

Analytica Chimica Acta, 1985

Research paper thumbnail of ICP-AES investigation on heavy metal water and soil pollution in Plovdiv Region (Bulgaria)

ABSTRACT The aim of this environmental study is to establish the distribution and the interaction... more ABSTRACT The aim of this environmental study is to establish the distribution and the interaction of heavy metal water and soil pollution in Plovdiv - Assenovgrad region due to mining and metallurgical activities. The main pollution source is the smelter factory “KCM”, situated south of the town of Plovdiv. The dynamics and the evolution of concentration levels of a large number of major and trace elements as impurities in various water (underground, surface, wastewaters) and soil were investigated. The measurements were performed with high-resolution inductively coupled plasma atomic emission spectrometer (ICP – AES) ULTIMA 2, Jobin Yvon France. ISO 11885 – “Water quality. Determination of 33 elements by ICP-AES” was used as a basis in the analysis of water samples. The “best” analysis lines in the determination of elements in soils were chosen by the Q-concept as proposed by P.W.J.M. Boumans and J.J.A.M. Vrakking. Comparative data were obtained by solid sampling with direct current arc - atomic emission spectrometry and atomic absorption spectrometry (AAS). The observed nature and magnitude of the hazards in Plovdiv region appears to be depending on the complex combination of many factors. The hydrogeochemical monitoring carried out is especially important giving possibilities for limitation of the industrial pollution and recovery of the environmental equilibrium.

Research paper thumbnail of Retention of Cs in Boom Clay: Comparison of data from batch sorption tests and diffusion experiments on intact clay cores

Physics and Chemistry of the Earth, Parts A/B/C, 2008

... 2) compares well with previous published data ([Baeyens, 1982], [Bradbury and Baeyens, 2000] ... more ... 2) compares well with previous published data ([Baeyens, 1982], [Bradbury and Baeyens, 2000] and [De Preter et al., 1991]) and can be approximated by a Freundlich isotherm (C ads = K f × View the MathML source , with K f the distribution coefficient in case of a Freundlich ...

Research paper thumbnail of Application of high-resolution 40.68 MHz radial-viewing inductively coupled plasma optical emission spectrometry in rhenium determination

Geologica Balcanica, 2017

The possibilities of 40.68 MHz radial-viewing inductively coupled plasma optical emission spectro... more The possibilities of 40.68 MHz radial-viewing inductively coupled plasma optical emission spectrometry equipped with a high-resolution spectrometer (spectral bandwidth = 5 pm) (HR-ICP-OES) were studied in the determination of rhenium in molybdenum and copper concentrates. By using equipment with a high spectral resolution, a hyperfine structure (HFS) of the most prominent lines of rhenium (i.e., Re II 197.248 nm, Re II 221.426 nm and Re II 227.525 nm) were registered. The HFS components, under high-resolution conditions, were used as separate prominent lines in order to circumvent spectral interferences in the presence of complex matrix containing Mo, Al, Ti, Fe, Mg, Ca and Cu. The Q-concept was applied for quantification of the spectral interferences and optimum line selection. Microwave acid digestion method was used as a sample dissolution procedure. The feasibility, accuracy and precision of the analytical results were experimentally demonstrated by certified reference materials...

Research paper thumbnail of Retention of Cs in Boom Clay: Comparison of data from batch sorption tests and diffusion experiments on intact clay cores

Physics and Chemistry of the Earth, Parts A/B/C, 2008

... 2) compares well with previous published data ([Baeyens, 1982], [Bradbury and Baeyens, 2000] ... more ... 2) compares well with previous published data ([Baeyens, 1982], [Bradbury and Baeyens, 2000] and [De Preter et al., 1991]) and can be approximated by a Freundlich isotherm (C ads = K f × View the MathML source , with K f the distribution coefficient in case of a Freundlich ...

Research paper thumbnail of Heavy metal and metalloid mobilisation and rates of contamination of water, soil and bottom sediments in the Chiprovtsi mining district, Northwestern Bulgaria

<jats:p>Geochemical studies of seasonally collected mine, stream and drinking waters, botto... more <jats:p>Geochemical studies of seasonally collected mine, stream and drinking waters, bottom sediments (mine and stream) and soil samples from all mining sections were carried out in order to assess the rates of pollution in the immediate proximity to underground mining facilities and related waste rock dumps. The determined concentrations of studied elements in water (As, Pb, Cu, Zn and Sb) show spatial distribution corresponding to ore mineralisation in different sections. Arsenic concentrations show gradual decrease in west-east direction, whereas Pb concentrations peak in the central and eastern sections. Arsenic and, to a lesser extent, Pb proved to be major pollutants in mine and surface waters, as well as in bottom sediments and soils. Detailed geochemical study of soils revealed strong spatial relation with host rocks and ore mineralogy. Comparisons with state guidelines for harmful elements revealed that alluvial and meadow soils in close proximity to waste dumps contain As, Pb, Cu, Zn and Cd above maximum permissible levels. It was also found that, compared to other Bulgarian and world alluvial (fluvisol) soils and the upper continental crust, the soils in Chiprovtsi mining district are enriched in Te, Re, W, Pd, Au, Ag, Mo, Ti, Mn, Co, Se, Sb, Bi and Cs. Since the processes of weathering and oxidation of mine waste remaining in the area continue naturally, the pollution with As and Pb will presumably carry on with decreasing effect.</jats:p>

Research paper thumbnail of Determination of arsenic, mercury, selenium, thallium, tin and bismuth in environmental materials by inductively coupled plasma emission spectrometry

Spectrochimica Acta Part B: Atomic Spectroscopy, 2004

Research paper thumbnail of Heavy Metal Mobility and Speciation in Coal Ash Reclaimed Hydrophobic Mine Soils

World Academy of Science, Engineering and Technology, International Journal of Agricultural and Biosystems Engineering, 2018

Research paper thumbnail of Spectral interferences in the determination of rhenium in molybdenum and copper concentrates by inductively coupled plasma optical emission spectrometry (ICP-OES)

Spectrochimica Acta Part B: Atomic Spectroscopy, 2016

Research paper thumbnail of Heavy metal mobility in soils under the application of sewage sludge

Bulgarian Journal of Agricultural Science

One of the main issues relating to sewage sludge (SS ) disposal is the introduction of heavy meta... more One of the main issues relating to sewage sludge (SS ) disposal is the introduction of heavy metals and organic pollutants. The aim of this research work was to assess the mobility of heavy metals via measurement of the soluble and easily exchangeable metals in soils on which sewage sludge had been deposited 10 years before analysis and clarify patterns and relationships between heavy metals in the amended soils as opposed to un-amended control soils. There are few studies on the leaching potential of heavy metals in sludge-amended soils through measurement of the soluble and easily exchangeable metal forms. Mobile heavy metals (soluble + easily exchangeable Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn) were measured via extraction with 0.05 M Ca(NO 3)2. We observed: (i) elevated Cd, Cr, Zn and Cu concentrations in the sludge treated soils; (ii) no effect of sludge application was found, as far as Pb, Mn, Fe, Ni and Co mobilities are concerned; (iii) the statistical analysis showed that sl...

Research paper thumbnail of Dynamics and evolution of heavy metal water pollution in the Plovdiv region (Bulgaria)

Research paper thumbnail of Determination of Y, Zr, Nb, Hf, Ta and Th in geological materials by inductively coupled plasma emission spectrometry

This paper deals with spectral interferences in radial - viewing Inductively Coupled Plasma Atomi... more This paper deals with spectral interferences in radial - viewing Inductively Coupled Plasma Atomic Emission Spectrometry (lCP-AES) in the determination of Y, Zr, Nb, Hf, Ta and Th in geological materials.The spectral interferences in the presence of Al, Ca, Mg, Fe, Ti, Mn, Na, K and P as maffix constituents around the prominent lines of analytes were studied. Q -values for line interference [QIJ (a)] and Q-values for wing background interference [QWJ(Δλa)] were obtained for quantification of spectral interferencesin the presence of multicomponent eological matrix. The prominent lines free or negligibly influenced by multicomponent line interference were selected for analyte determination. Q -values were used for optimum line selection and for calculation of the true detection limits. Comparison of the magnitude of the spectral interferences and the detection limits in the presence of geological samples by using ICP-AES equipmen with different ICP frequencies and the spectrometer ty...

Research paper thumbnail of Posibilities of Inductively Coupled Plasma Optical Emmission Spectrometry (Icp-Oes) in the Determination of Rare and Trace Elements

The economic and geological importance of Zr, Nb, Hf, Ta, Th, Pt, Pd, Rh and rare earth elements ... more The economic and geological importance of Zr, Nb, Hf, Ta, Th, Pt, Pd, Rh and rare earth elements has led to the development of analytical methods, which have to ensure their accurate quantification in different type of samples. Radial viewing 40.68 MHz inductively coupled plasma optical emission spectrometry (ICP-OES) and Q - concept for the quantification of spectral interference were used in the determination of these elements in materials with variable matrix constituents. The accuracy of the results was experimentally demonstrated by using certified reference materials. Improvement of the detection limits was achieved by optimization of the operating conditions. Keywords: ICP-OES, geological samples, Eu2O3, Zr, Nb, Hf, Ta, Th, Pt, Pd, Rh, Y, Sc, rare earth elements;

Research paper thumbnail of Determination of As, Zn, Pt, B, Hg, Cd, Tl and U in environmental materials by high resolution radial viewing 40.68 MHz inductively coupled plasma optical emission spectrometry (ICP - OES)

Bulgarian Chemical Communications

The possibilities and limitations of high resolution radial viewing 40.68 MHz inductively coupled... more The possibilities and limitations of high resolution radial viewing 40.68 MHz inductively coupled plasma optical emission spectrometry (ICP - OES) were shown in the determination of As, Zn, Pt, B, Hg, Cd, Tl and U in environmental materials. Improvement of the detection limits was achieved by optimization of the operating conditions. The lowest detection limits were obtained under robust conditions (excitation temperature ≈ 7200 K in pure solvent and in presence of Al, Ca, Fe, Mg and Ti as a complex environmental matrix). The detection limits in the determination of As, Zn, B, Hg, Cd, Tl and U satisfy the requirements for maximum permissible concentrations in soils and drinking waters. In the determination of Pt in road dust an improvement of the detection limit was achieved by the development of a new column method with 2-mercaptobenzimidazole immobilized on activated carbon for separation of the matrix elements Al, Ca, Fe, Mg and Ti and pre-concentration of platinum.

Research paper thumbnail of Possibilities of High Resolution Inductively Coupled Plasma Optical Emission Spectrometry in the Determination of Trace Elements in Environmental Materials

Journal of Spectroscopy, 2013

This paper presents new quantitative data for the spectral interferences obtained by high resolut... more This paper presents new quantitative data for the spectral interferences obtained by high resolution 40.68 MHz radial viewing inductively coupled plasma optical emission spectrometry (HR-ICP-OES) in the determination of Zn, Cd, Sb, Cu, Mn, Pb, Sn, Cr, U, and Ba in environmental materials in the presence of a complex matrix, containing Al, Ca, Fe, Mg, and Ti. The-concept for quantification of spectral interferences was used. The optimum line selection for trace analysis of a variety of multicomponent matrices requires the choice of prominent lines, which are free or negligibly influenced by line interference problems. The versatility of-concept as basic methodology was experimentally demonstrated in the determination of trace of elements in soil and drinking water. The detection limits are lower in comparison with corresponding threshold concentration levels for soil and drinking water in accordance with environmental regulations. This paper shows the possibilities of present day ICP-OES equipment in the direct determination of trace elements (without preconcentration of impurities) in environmental samples.

Research paper thumbnail of Problems, possibilities and limitations of inductively coupled plasma atomic emission spectrometry in the determination of platinum, palladium and rhodium in samples with different matrix composition

Spectrochimica Acta Part B: Atomic Spectroscopy, 2010

The economic and geological importance of platinum group of elements has led to the development o... more The economic and geological importance of platinum group of elements has led to the development of analytical methods to quantify them in different types of samples. In the present paper the quantitative information for spectral interference in radial viewing 40.68 MHz inductively coupled plasma atomic emission spectrometry in the determination of Pt, Pd and Rh in the presence of complex matrix, containing Al, Ca, Fe, Mg, Mn, P and Ti as matrix constituents was obtained. The database was used for optimum line selections. By using the selected analysis lines the following detection limits in ng g − 1 were obtained: Pt 1700, Pd-1440, Rh-900. The reached detection limits determine the possibilities and limitation of the direct ICP-AES method in the determination of Pt, Pd and Rh in geological and environmental materials. The database for spectral interferences in the presence of aluminum can be used for the determination of platinum group of elements in car catalysts. The accuracy of the analytical results was experimentally demonstrated by two certified reference materials that were analyzed: SARM 7, Pt ore and recycled auto-catalyst certified reference material SRM 2556.

Research paper thumbnail of Inductively Coupled Plasma-Atomic Emission Spectroscopy: Two Laboratory Activities for the Undergraduate Instrumental Analysis Course

Journal of Chemical Education, 2003

Research paper thumbnail of Heavy metal and metalloid concentrationdynamics in mine and surface waters in the vicinity of Chiprovtsi and Martinovo, mines, northwestern Bulgaria

Chiprovtsi silver-lead and Martinovo iron mines represent the biggest mining area in Northwestern... more Chiprovtsi silver-lead and Martinovo iron mines represent the biggest mining area in Northwestern Bulgaria, which was operated till 1999. Their long-lived operation leads to proved pollution of the environment in the vicinity of the mines, especially water and soil. Seasonal monitoring of heavy metal (Cu, Zn, Cd and Pb) and metalloid (As and Sb) concentrations in mine, surface (river) and drinking waters was carried out during May and August 2006 to determine the level of contamination of the Chiprovska Ogosta river basin resulting from the long-lived mining activity and whether these abandoned mines continue to be potential source for water pollution. This study proves significant As concentrations in mine (up to 170 μg/l) and surface waters (between 50 and 621 μg/l). The presence of other heavy metals, such as Cu, Cd, Zn and Pb, and metalloid-Sb is also recorded. Among them, Pb was found in considerable concentrationsup to 1456 pg/l during May 2006 sampling exhibiting great concentration variability between dry and wet sampling seasons. Sb is also determined in mine waters (up to 25 pg/l), but not exists in surface and drinking waters. Drinking waters are proved to be free of heavy metals and metalloids.

Research paper thumbnail of Application of inductively-coupled plasma atomic emission spectrometry with an internal reference to the determination of sulfate and calcium in waters and brines

Analytica Chimica Acta, 1985

Research paper thumbnail of ICP-AES investigation on heavy metal water and soil pollution in Plovdiv Region (Bulgaria)

ABSTRACT The aim of this environmental study is to establish the distribution and the interaction... more ABSTRACT The aim of this environmental study is to establish the distribution and the interaction of heavy metal water and soil pollution in Plovdiv - Assenovgrad region due to mining and metallurgical activities. The main pollution source is the smelter factory “KCM”, situated south of the town of Plovdiv. The dynamics and the evolution of concentration levels of a large number of major and trace elements as impurities in various water (underground, surface, wastewaters) and soil were investigated. The measurements were performed with high-resolution inductively coupled plasma atomic emission spectrometer (ICP – AES) ULTIMA 2, Jobin Yvon France. ISO 11885 – “Water quality. Determination of 33 elements by ICP-AES” was used as a basis in the analysis of water samples. The “best” analysis lines in the determination of elements in soils were chosen by the Q-concept as proposed by P.W.J.M. Boumans and J.J.A.M. Vrakking. Comparative data were obtained by solid sampling with direct current arc - atomic emission spectrometry and atomic absorption spectrometry (AAS). The observed nature and magnitude of the hazards in Plovdiv region appears to be depending on the complex combination of many factors. The hydrogeochemical monitoring carried out is especially important giving possibilities for limitation of the industrial pollution and recovery of the environmental equilibrium.

Research paper thumbnail of Retention of Cs in Boom Clay: Comparison of data from batch sorption tests and diffusion experiments on intact clay cores

Physics and Chemistry of the Earth, Parts A/B/C, 2008

... 2) compares well with previous published data ([Baeyens, 1982], [Bradbury and Baeyens, 2000] ... more ... 2) compares well with previous published data ([Baeyens, 1982], [Bradbury and Baeyens, 2000] and [De Preter et al., 1991]) and can be approximated by a Freundlich isotherm (C ads = K f × View the MathML source , with K f the distribution coefficient in case of a Freundlich ...