TY  - JOUR
AU  - Pastor, Ferenc
AU  - Dejmkova, Hana
AU  - Zima, Jiri
AU  - Barek, Jiri
PY  - 2011
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/1334
AB  - The possibility of determination of chloramphenicol by differential pulse voltammetry at four different carbon paste electrodes, in the full pH range (2-12) of Britton-Robinson (BR) buffer was investigated. Electrodes were prepared by mixing spectroscopic graphite powder or glassy carbon microbeads with mineral oil (Nujol) or tricresyl phosphate. Under optimal conditions (BR buffer pH 12, the electrode prepared from glassy carbon microbeads and tricresyl phosphate), linear calibration graph was obtained only in 10-5 M chloramphenicol concentration range. Determination of lower concentrations of chloramphenicol was complicated by irreproducible peak of oxygen from the carbon paste which overlapped with peak of chloramphenicol. Addition of sodium sulfite removed the oxygen peak without influence on the peak of chloramphenicol. Under optimal conditions (electrode paste made from glassy carbon microbeads, BR buffer pH 10 and 0.5 M sodium sulfite), straight calibration line was obtained in the 10(-6) and 10(-5) M chloramphenicol concentration range. Limit of determination was 5 x 10(-7) mol/l.
PB  - Inst Organic Chem And Biochem, Prague 6
T2  - Collection of Czechoslovak Chemical Communications
T1  - Determination of Chloramphenicol by Differential Pulse Voltammetry at Carbon Paste Electrodes - the Use of Sodium Sulfite for Removal of Oxygen from  Electrode Surface
VL  - 76
IS  - 5
SP  - 383
EP  - 397
DO  - 10.1135/cccc2011011
ER  - 

@article{
author = "Pastor, Ferenc and Dejmkova, Hana and Zima, Jiri and Barek, Jiri",
year = "2011",
abstract = "The possibility of determination of chloramphenicol by differential pulse voltammetry at four different carbon paste electrodes, in the full pH range (2-12) of Britton-Robinson (BR) buffer was investigated. Electrodes were prepared by mixing spectroscopic graphite powder or glassy carbon microbeads with mineral oil (Nujol) or tricresyl phosphate. Under optimal conditions (BR buffer pH 12, the electrode prepared from glassy carbon microbeads and tricresyl phosphate), linear calibration graph was obtained only in 10-5 M chloramphenicol concentration range. Determination of lower concentrations of chloramphenicol was complicated by irreproducible peak of oxygen from the carbon paste which overlapped with peak of chloramphenicol. Addition of sodium sulfite removed the oxygen peak without influence on the peak of chloramphenicol. Under optimal conditions (electrode paste made from glassy carbon microbeads, BR buffer pH 10 and 0.5 M sodium sulfite), straight calibration line was obtained in the 10(-6) and 10(-5) M chloramphenicol concentration range. Limit of determination was 5 x 10(-7) mol/l.",
publisher = "Inst Organic Chem And Biochem, Prague 6",
journal = "Collection of Czechoslovak Chemical Communications",
title = "Determination of Chloramphenicol by Differential Pulse Voltammetry at Carbon Paste Electrodes - the Use of Sodium Sulfite for Removal of Oxygen from  Electrode Surface",
volume = "76",
number = "5",
pages = "383-397",
doi = "10.1135/cccc2011011"
}

Pastor, F., Dejmkova, H., Zima, J.,& Barek, J.. (2011). Determination of Chloramphenicol by Differential Pulse Voltammetry at Carbon Paste Electrodes - the Use of Sodium Sulfite for Removal of Oxygen from  Electrode Surface. in Collection of Czechoslovak Chemical Communications
Inst Organic Chem And Biochem, Prague 6., 76(5), 383-397.
https://doi.org/10.1135/cccc2011011

Pastor F, Dejmkova H, Zima J, Barek J. Determination of Chloramphenicol by Differential Pulse Voltammetry at Carbon Paste Electrodes - the Use of Sodium Sulfite for Removal of Oxygen from  Electrode Surface. in Collection of Czechoslovak Chemical Communications. 2011;76(5):383-397.
doi:10.1135/cccc2011011 .

Pastor, Ferenc, Dejmkova, Hana, Zima, Jiri, Barek, Jiri, "Determination of Chloramphenicol by Differential Pulse Voltammetry at Carbon Paste Electrodes - the Use of Sodium Sulfite for Removal of Oxygen from  Electrode Surface" in Collection of Czechoslovak Chemical Communications, 76, no. 5 (2011):383-397,
https://doi.org/10.1135/cccc2011011 . .

TY  - JOUR
AU  - Stevic, Milica C.
AU  - Ignjatovic, Ljubisa M.
AU  - Ćirić-Marjanović, Gordana
AU  - Stanišić, Svetlana M.
AU  - Stanković, Dalibor
AU  - Zima, Jiri
PY  - 2011
UR  - https://cherry.chem.bg.ac.rs/handle/123456789/1171
AB  - The 8-Hydroxyquinoline (8HQ) oxidation process has been investigated by Cyclic Voltammetry using a Glassy Carbon Paste Electrode (GCPE) as a working electrode. The theoretical study of the mechanism of electrochemical oxidation of 8HQ has been based on the AM1 semi-empirical quantum chemical computations of the heats of formation of the reaction intermediates, taking into account the influence of pH and solvation effects. We proposed that a two-electron irreversible process, controlled by diffusion of electroactive species, is responsible for an oxidation peak of 8HQ that appears in all cyclic voltammograms recorded on a clean electrode in the solutions of pH in the range 2-12 with a supporting electrolyte of Britton-Robinson Buffer/methanol. A single-electron oxidation of 8HQ leads, depending on pH, to the formation of various free radical species that combine to make dimers which, after being oxidized once more, give quinonoid-type compounds. Recording continuous cyclic voltammograms on the GCPE, pre-peaks appear as a consequence of dimer and quinonoid compounds formation. By applying Differential Pulse Voltammetry for 8HQ determination it was calculated that the limit of detection was 5.2x10(-8) mol/L. For more sensitive quantitative determination of the investigated substance Adsorptive Stripping Differential Pulse Voltammery can be used since it was found that after 300s-deposition time at 0.0 V vs. Saturated Calomel Electrode, a 2.1 times higher peak current than without deposition was obtained.
PB  - Electrochemical Science Group, Belgrade
T2  - International Journal of Electrochemical Science
T1  - Voltammetric Behaviour and Determination of 8-Hydroxyquinoline Using a Glassy Carbon Paste Electrode and the Theoretical Study of its Electrochemical Oxidation Mechanism
VL  - 6
IS  - 7
SP  - 2509
EP  - 2525
UR  - https://hdl.handle.net/21.15107/rcub_cherry_1171
ER  - 

@article{
author = "Stevic, Milica C. and Ignjatovic, Ljubisa M. and Ćirić-Marjanović, Gordana and Stanišić, Svetlana M. and Stanković, Dalibor and Zima, Jiri",
year = "2011",
abstract = "The 8-Hydroxyquinoline (8HQ) oxidation process has been investigated by Cyclic Voltammetry using a Glassy Carbon Paste Electrode (GCPE) as a working electrode. The theoretical study of the mechanism of electrochemical oxidation of 8HQ has been based on the AM1 semi-empirical quantum chemical computations of the heats of formation of the reaction intermediates, taking into account the influence of pH and solvation effects. We proposed that a two-electron irreversible process, controlled by diffusion of electroactive species, is responsible for an oxidation peak of 8HQ that appears in all cyclic voltammograms recorded on a clean electrode in the solutions of pH in the range 2-12 with a supporting electrolyte of Britton-Robinson Buffer/methanol. A single-electron oxidation of 8HQ leads, depending on pH, to the formation of various free radical species that combine to make dimers which, after being oxidized once more, give quinonoid-type compounds. Recording continuous cyclic voltammograms on the GCPE, pre-peaks appear as a consequence of dimer and quinonoid compounds formation. By applying Differential Pulse Voltammetry for 8HQ determination it was calculated that the limit of detection was 5.2x10(-8) mol/L. For more sensitive quantitative determination of the investigated substance Adsorptive Stripping Differential Pulse Voltammery can be used since it was found that after 300s-deposition time at 0.0 V vs. Saturated Calomel Electrode, a 2.1 times higher peak current than without deposition was obtained.",
publisher = "Electrochemical Science Group, Belgrade",
journal = "International Journal of Electrochemical Science",
title = "Voltammetric Behaviour and Determination of 8-Hydroxyquinoline Using a Glassy Carbon Paste Electrode and the Theoretical Study of its Electrochemical Oxidation Mechanism",
volume = "6",
number = "7",
pages = "2509-2525",
url = "https://hdl.handle.net/21.15107/rcub_cherry_1171"
}

Stevic, M. C., Ignjatovic, L. M., Ćirić-Marjanović, G., Stanišić, S. M., Stanković, D.,& Zima, J.. (2011). Voltammetric Behaviour and Determination of 8-Hydroxyquinoline Using a Glassy Carbon Paste Electrode and the Theoretical Study of its Electrochemical Oxidation Mechanism. in International Journal of Electrochemical Science
Electrochemical Science Group, Belgrade., 6(7), 2509-2525.
https://hdl.handle.net/21.15107/rcub_cherry_1171

Stevic MC, Ignjatovic LM, Ćirić-Marjanović G, Stanišić SM, Stanković D, Zima J. Voltammetric Behaviour and Determination of 8-Hydroxyquinoline Using a Glassy Carbon Paste Electrode and the Theoretical Study of its Electrochemical Oxidation Mechanism. in International Journal of Electrochemical Science. 2011;6(7):2509-2525.
https://hdl.handle.net/21.15107/rcub_cherry_1171 .

Stevic, Milica C., Ignjatovic, Ljubisa M., Ćirić-Marjanović, Gordana, Stanišić, Svetlana M., Stanković, Dalibor, Zima, Jiri, "Voltammetric Behaviour and Determination of 8-Hydroxyquinoline Using a Glassy Carbon Paste Electrode and the Theoretical Study of its Electrochemical Oxidation Mechanism" in International Journal of Electrochemical Science, 6, no. 7 (2011):2509-2525,
https://hdl.handle.net/21.15107/rcub_cherry_1171 .