TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera S.
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5964
AB  - In the era of pollution and hazardous materials, new methods for the detection of pollutants
in the environment are urgently needed. Due to their specific features such as
photoluminescence (PL) in the visible part of the spectrum, dispersibility in water, and
organic solvents, nontoxicity, and biocompatibility, graphene quantum dots (GQDs) attract
attention in optical sensing of various ions and molecules. In this study, pristine graphene
quantum dots (p-GQDs) were produced in a simple single-step electrochemical top-down
approach using graphite electrodes as a starting material, and dispersion of sodiumhydroxide
in 96% ethanol as a medium for electrochemical reaction. These p-GQDs were
gamma-irradiated in a dose of 25 kGy in presence of ethylenediamine in Ar medium to
introduce amino groups in their crystal lattice. Results obtained from AFM microscopy
indicate the height-uniformity of irradiated GQDs. The presence of amino groups in GQDs
was confirmed by FTIR, XPS, and UV-Vis spectroscopies. According to results obtained
from PL spectroscopy, a significant narrowing of emission band in irradiated GQDs was
observed. In further research, these GQDs were investigated as a potential PL sensor for iron
which is one of the most abundant heavy metal in the environment. In the preliminary
investigation, a water dispersion of irradiated GQDs was mixed with Fe(III) solution in
concentrations of 50 and 100 μM. Using a PL spectroscopy the PL intensity of irradiated
GQDs in presence of Fe (III) was measured. From the obtained results, it can be seen that
Fe(III) ions lead to quenching of GQDs PL intensity. Then, PL intensities were measured in
presence of Fe(III) ions in concentration range 0-100 μM. With an increase of Fe(III)
concentration, the PL intensity of GQDs decreased. It can be concluded that gammairradiated
amino-doped GQDs have significant potential in the so-called ,,turn of“ detection
of Fe(III) ions in the aqueous medium.
PB  - Belgrade : Institute of Technical Sciences of SASA
C3  - Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia
T1  - Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions
SP  - 35
EP  - 35
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5964
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera S. and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "In the era of pollution and hazardous materials, new methods for the detection of pollutants
in the environment are urgently needed. Due to their specific features such as
photoluminescence (PL) in the visible part of the spectrum, dispersibility in water, and
organic solvents, nontoxicity, and biocompatibility, graphene quantum dots (GQDs) attract
attention in optical sensing of various ions and molecules. In this study, pristine graphene
quantum dots (p-GQDs) were produced in a simple single-step electrochemical top-down
approach using graphite electrodes as a starting material, and dispersion of sodiumhydroxide
in 96% ethanol as a medium for electrochemical reaction. These p-GQDs were
gamma-irradiated in a dose of 25 kGy in presence of ethylenediamine in Ar medium to
introduce amino groups in their crystal lattice. Results obtained from AFM microscopy
indicate the height-uniformity of irradiated GQDs. The presence of amino groups in GQDs
was confirmed by FTIR, XPS, and UV-Vis spectroscopies. According to results obtained
from PL spectroscopy, a significant narrowing of emission band in irradiated GQDs was
observed. In further research, these GQDs were investigated as a potential PL sensor for iron
which is one of the most abundant heavy metal in the environment. In the preliminary
investigation, a water dispersion of irradiated GQDs was mixed with Fe(III) solution in
concentrations of 50 and 100 μM. Using a PL spectroscopy the PL intensity of irradiated
GQDs in presence of Fe (III) was measured. From the obtained results, it can be seen that
Fe(III) ions lead to quenching of GQDs PL intensity. Then, PL intensities were measured in
presence of Fe(III) ions in concentration range 0-100 μM. With an increase of Fe(III)
concentration, the PL intensity of GQDs decreased. It can be concluded that gammairradiated
amino-doped GQDs have significant potential in the so-called ,,turn of“ detection
of Fe(III) ions in the aqueous medium.",
publisher = "Belgrade : Institute of Technical Sciences of SASA",
journal = "Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia",
title = "Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions",
pages = "35-35",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5964"
}

Dorontić, S., Marković, O. S., Kleut, D.,& Jovanović, S.. (2021). Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions. in Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia
Belgrade : Institute of Technical Sciences of SASA., 35-35.
https://hdl.handle.net/21.15107/rcub_cherry_5964

Dorontić S, Marković OS, Kleut D, Jovanović S. Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions. in Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia. 2021;:35-35.
https://hdl.handle.net/21.15107/rcub_cherry_5964 .

Dorontić, Slađana, Marković, Olivera S., Kleut, Duška, Jovanović, Svetlana, "Graphene quantum dots with amino groups as a potential photoluminescent probe for Fe(III) ions" in Nineteenth Young Researchers’ Conference Materials Science and Engineering, December 1-3, 2021, Belgrade, Serbia (2021):35-35,
https://hdl.handle.net/21.15107/rcub_cherry_5964 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera S.
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5966
AB  - We produced Graphene Quantum Dots (GQDs) by electrochemical oxidation of graphite rods and exposed them to gamma irradiation at a dose of 200 kGy, in the presence of ethylene-diamine. Before irradiation, oxygen was removed from the GQDs dispersion by purging with Ar. These conditions induced both chemical reduction as well as the incorporation of N atoms in the structure of GQDs. Thus, N-doped GQDs were produced. The morphology of dots was investigated using atomic force microscopy. UV-Vis and photoluminescence spectroscopy were used to investigate the optical properties of modified GQDs. The changes in the intensities of PL emission spectra were studied in the presence of different concentrations of Pd2+ and pesticide carbofuran. We observed promising results for the application of N-doped GQDs for non-enzymatic PL detection of selected metal ions and molecules of pesticide.
PB  - Szeged : University of Szeged
C3  - 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021
T1  - N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran
SP  - 143
EP  - 147
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5966
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera S. and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "We produced Graphene Quantum Dots (GQDs) by electrochemical oxidation of graphite rods and exposed them to gamma irradiation at a dose of 200 kGy, in the presence of ethylene-diamine. Before irradiation, oxygen was removed from the GQDs dispersion by purging with Ar. These conditions induced both chemical reduction as well as the incorporation of N atoms in the structure of GQDs. Thus, N-doped GQDs were produced. The morphology of dots was investigated using atomic force microscopy. UV-Vis and photoluminescence spectroscopy were used to investigate the optical properties of modified GQDs. The changes in the intensities of PL emission spectra were studied in the presence of different concentrations of Pd2+ and pesticide carbofuran. We observed promising results for the application of N-doped GQDs for non-enzymatic PL detection of selected metal ions and molecules of pesticide.",
publisher = "Szeged : University of Szeged",
journal = "27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021",
title = "N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran",
pages = "143-147",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5966"
}

Dorontić, S., Marković, O. S., Kleut, D.,& Jovanović, S.. (2021). N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran. in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021
Szeged : University of Szeged., 143-147.
https://hdl.handle.net/21.15107/rcub_cherry_5966

Dorontić S, Marković OS, Kleut D, Jovanović S. N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran. in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021. 2021;:143-147.
https://hdl.handle.net/21.15107/rcub_cherry_5966 .

Dorontić, Slađana, Marković, Olivera S., Kleut, Duška, Jovanović, Svetlana, "N-doped graphene quantum dots for detection of palladium(II) ions and carbofuran" in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021 (2021):143-147,
https://hdl.handle.net/21.15107/rcub_cherry_5966 .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera S.
AU  - Kleut, Duška
AU  - Jovanović, Svetlana
PY  - 2021
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5967
AB  - Graphene quantum dots (GQDs) were fabricated by simple electrochemical oxidation of graphite electrodes. Modified GQDs were obtained by gamma irradiation of GQDs, EDA, and IPA mixture at a dose of 25 kGy. In this approach, GQDs with the amino groups were produced (25γ-GQDs). These GQDs have shown a high uniformity, good dispersibility in water, and strong photoluminescence in the blue part of the electromagnetic spectrum. Modified GQDs were studied in the optical detection of Co2+ ions. The PL intensities of GQDs were measured in the presence of Co2+ ions in the concentration range 0-7.5 μmol L-1. It was demonstrated that PL intensities decreased linearly in the concentration range 0-2.5 μmol L-1. The value of the coefficient of determination (R2= 0.95949) indicates the potential of 25γ-GQDs for application in optical sensing of Co2+ ions.
PB  - Szeged : University of Szeged
C3  - 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021
T1  - Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions
SP  - 107
EP  - 111
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5967
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera S. and Kleut, Duška and Jovanović, Svetlana",
year = "2021",
abstract = "Graphene quantum dots (GQDs) were fabricated by simple electrochemical oxidation of graphite electrodes. Modified GQDs were obtained by gamma irradiation of GQDs, EDA, and IPA mixture at a dose of 25 kGy. In this approach, GQDs with the amino groups were produced (25γ-GQDs). These GQDs have shown a high uniformity, good dispersibility in water, and strong photoluminescence in the blue part of the electromagnetic spectrum. Modified GQDs were studied in the optical detection of Co2+ ions. The PL intensities of GQDs were measured in the presence of Co2+ ions in the concentration range 0-7.5 μmol L-1. It was demonstrated that PL intensities decreased linearly in the concentration range 0-2.5 μmol L-1. The value of the coefficient of determination (R2= 0.95949) indicates the potential of 25γ-GQDs for application in optical sensing of Co2+ ions.",
publisher = "Szeged : University of Szeged",
journal = "27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021",
title = "Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions",
pages = "107-111",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5967"
}

Dorontić, S., Marković, O. S., Kleut, D.,& Jovanović, S.. (2021). Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions. in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021
Szeged : University of Szeged., 107-111.
https://hdl.handle.net/21.15107/rcub_cherry_5967

Dorontić S, Marković OS, Kleut D, Jovanović S. Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions. in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021. 2021;:107-111.
https://hdl.handle.net/21.15107/rcub_cherry_5967 .

Dorontić, Slađana, Marković, Olivera S., Kleut, Duška, Jovanović, Svetlana, "Amino functionalized graphene quantum dots - new fluorescent sensor for CO2+ ions" in 27th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 22-23, 2021 (2021):107-111,
https://hdl.handle.net/21.15107/rcub_cherry_5967 .

TY  - JOUR
AU  - Jovanović, Svetlana
AU  - Dorontić, Slađana
AU  - Jovanović, Dragana
AU  - Ciasca, Gabriele
AU  - Budimir, Milica D.
AU  - Bonasera, Aurelio
AU  - Scopelliti, Michelangelo
AU  - Marković, Olivera S.
AU  - Todorović Marković, Biljana
PY  - 2020
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5466
AB  - Due to the low consumption of chemicals, the absence of toxic residual side products, the procedure simplicity
and time-saving aspects, gamma irradiation offers advantages over the classical chemical protocols. We suc cessfully employed gamma irradiation in order to introduce N-atoms in Graphene Quantum Dots (GQDs). By
irradiating GQDs water dispersions in the presence of isopropyl alcohol and ethylenediamine, at doses of 25, 50
and 200 kGy, we attached amino groups onto GQDs in a single synthetic step. At the same time, a chemical
reduction is achieved, too. Selected conditions induced incorporation of N-atoms within GDQs atomic lattice
(around 3 at%), at all applied doses. Additionally, the C-atoms percentage was highly increased, from 63 to 79 at
% or higher. The zeta potential of dots changed from −34.6 to +9.1 mV, due to the modification of functio nalizing groups localized at the surface. Produced chemical changes lead to the desired alteration of the GQDs
optical properties, such as an increased photoluminescence intensity, a higher photoluminescence quantum
yields (from 2.07 to 18.40%) and a narrowing of the spectral features in the emission spectra. The ability of
gamma-irradiated GQDs to quench free radical species was investigated and positively assessed; additionally,
non-enzymatic optical detection of Cu(II) ions using GQDs as a sensor was studied and the detection limits are
herein reported. These results suggest that GQDs can be potentially applied as smart photoluminescent sensors
for metal cations.
PB  - Elsevier
T2  - Ceramics International
T1  - Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing
VL  - 46
SP  - 23611
EP  - 23622
DO  - 10.1016/j.ceramint.2020.06.133
ER  - 

@article{
author = "Jovanović, Svetlana and Dorontić, Slađana and Jovanović, Dragana and Ciasca, Gabriele and Budimir, Milica D. and Bonasera, Aurelio and Scopelliti, Michelangelo and Marković, Olivera S. and Todorović Marković, Biljana",
year = "2020",
abstract = "Due to the low consumption of chemicals, the absence of toxic residual side products, the procedure simplicity
and time-saving aspects, gamma irradiation offers advantages over the classical chemical protocols. We suc cessfully employed gamma irradiation in order to introduce N-atoms in Graphene Quantum Dots (GQDs). By
irradiating GQDs water dispersions in the presence of isopropyl alcohol and ethylenediamine, at doses of 25, 50
and 200 kGy, we attached amino groups onto GQDs in a single synthetic step. At the same time, a chemical
reduction is achieved, too. Selected conditions induced incorporation of N-atoms within GDQs atomic lattice
(around 3 at%), at all applied doses. Additionally, the C-atoms percentage was highly increased, from 63 to 79 at
% or higher. The zeta potential of dots changed from −34.6 to +9.1 mV, due to the modification of functio nalizing groups localized at the surface. Produced chemical changes lead to the desired alteration of the GQDs
optical properties, such as an increased photoluminescence intensity, a higher photoluminescence quantum
yields (from 2.07 to 18.40%) and a narrowing of the spectral features in the emission spectra. The ability of
gamma-irradiated GQDs to quench free radical species was investigated and positively assessed; additionally,
non-enzymatic optical detection of Cu(II) ions using GQDs as a sensor was studied and the detection limits are
herein reported. These results suggest that GQDs can be potentially applied as smart photoluminescent sensors
for metal cations.",
publisher = "Elsevier",
journal = "Ceramics International",
title = "Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing",
volume = "46",
pages = "23611-23622",
doi = "10.1016/j.ceramint.2020.06.133"
}

Jovanović, S., Dorontić, S., Jovanović, D., Ciasca, G., Budimir, M. D., Bonasera, A., Scopelliti, M., Marković, O. S.,& Todorović Marković, B.. (2020). Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing. in Ceramics International
Elsevier., 46, 23611-23622.
https://doi.org/10.1016/j.ceramint.2020.06.133

Jovanović S, Dorontić S, Jovanović D, Ciasca G, Budimir MD, Bonasera A, Scopelliti M, Marković OS, Todorović Marković B. Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing. in Ceramics International. 2020;46:23611-23622.
doi:10.1016/j.ceramint.2020.06.133 .

Jovanović, Svetlana, Dorontić, Slađana, Jovanović, Dragana, Ciasca, Gabriele, Budimir, Milica D., Bonasera, Aurelio, Scopelliti, Michelangelo, Marković, Olivera S., Todorović Marković, Biljana, "Gamma irradiation of graphene quantum dots with ethylenediamine: Antioxidant for ion sensing" in Ceramics International, 46 (2020):23611-23622,
https://doi.org/10.1016/j.ceramint.2020.06.133 . .

TY  - CONF
AU  - Dorontić, Slađana
AU  - Marković, Olivera S.
AU  - Bonasera, Aurelio
AU  - Jovanović, Svetlana
PY  - 2020
UR  - http://cherry.chem.bg.ac.rs/handle/123456789/5961
AB  - Graphene Quantum Dots (GQDs) were produced using electrochemical oxidation of graphite rods. Obtained GQDs were gamma-irradiated in the presence of the N atoms source, ethylenediamine. Both structural and morphological changes were investigated using UV-Vis, X-ray photoelectron and photoluminescence (PL) spectroscopy as well as atomic force microscopy. The ability of both types of dots to change PL intensity in the presence of pesticides such as malathion and glyphosate, as well as copper (II) ions was detected. These preliminary results indicated a high potential of produced GQDs to be applied as non-enzymatic PL sensors for the detection of selected pesticides and metal ions.
PB  - Szeged : University of Szeged
C3  - The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020
T1  - Application of graphene quantum dots in heavy metals and pesticides detection
SP  - 179
EP  - 182
UR  - https://hdl.handle.net/21.15107/rcub_cherry_5961
ER  - 

@conference{
author = "Dorontić, Slađana and Marković, Olivera S. and Bonasera, Aurelio and Jovanović, Svetlana",
year = "2020",
abstract = "Graphene Quantum Dots (GQDs) were produced using electrochemical oxidation of graphite rods. Obtained GQDs were gamma-irradiated in the presence of the N atoms source, ethylenediamine. Both structural and morphological changes were investigated using UV-Vis, X-ray photoelectron and photoluminescence (PL) spectroscopy as well as atomic force microscopy. The ability of both types of dots to change PL intensity in the presence of pesticides such as malathion and glyphosate, as well as copper (II) ions was detected. These preliminary results indicated a high potential of produced GQDs to be applied as non-enzymatic PL sensors for the detection of selected pesticides and metal ions.",
publisher = "Szeged : University of Szeged",
journal = "The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020",
title = "Application of graphene quantum dots in heavy metals and pesticides detection",
pages = "179-182",
url = "https://hdl.handle.net/21.15107/rcub_cherry_5961"
}

Dorontić, S., Marković, O. S., Bonasera, A.,& Jovanović, S.. (2020). Application of graphene quantum dots in heavy metals and pesticides detection. in The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020
Szeged : University of Szeged., 179-182.
https://hdl.handle.net/21.15107/rcub_cherry_5961

Dorontić S, Marković OS, Bonasera A, Jovanović S. Application of graphene quantum dots in heavy metals and pesticides detection. in The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020. 2020;:179-182.
https://hdl.handle.net/21.15107/rcub_cherry_5961 .

Dorontić, Slađana, Marković, Olivera S., Bonasera, Aurelio, Jovanović, Svetlana, "Application of graphene quantum dots in heavy metals and pesticides detection" in The 26th International Symposium on Analytical and Environmental Problems, Szeged, Hungary November 23-24, 2020 (2020):179-182,
https://hdl.handle.net/21.15107/rcub_cherry_5961 .