Determination of Enalapril in Pharmaceuticals using Electrochemical Sensing with Amperometric Detection

In this work a new electrochemical method will be presented for the determination of enalapril in pharmaceutical tablets using unmodified screen printed electrode (SPE). The studies were done using amperommetric detection. Enalapril provides well defined, ovalshape oxidation peak at +1.05 V (vs. Ag/AgCl, 3.0 M KCl) in Britton-Robinson buffer solution (BRBS) at pH 5.0. After optimization of the experimental conditions, the influence of most common interferent compounds was tested. Under optimized experimental conditions, the signals were linearly proportional to the concentration of enalapril in the range from 2.5 to 90 mu M with a detection limit of 0.9 mu M. Repeatability of ten replicate measurements of 5 mu M enalapril was estimated to be 1.5%. Proposed method was successfully applied for the determination of the total amount of enalapril content in pharmaceutical preparations. Nevertheless, proposed method could be beneficial for the quick quantifications of enalapril in drugs using unmodified SPE electrode without any further treatment

Supplementary data for article: Stanković, D. M.; Mehmeti, E.; Svorc, L.; Kalcher, K. Simple, Rapid and Sensitive Electrochemical Method for the Determination of the Triketone Herbicide Sulcotrione in River Water Using a Glassy Carbon Electrode. Electroanalysis 2015, 27 (7), 1587–1593. https://doi.org/10.1002/elan.201400729

Supporting information for: [https://doi.org/10.1002/elan.201400729]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1731

Trends of the Contraceptive Medicine Consumption in Kosovo

One of the main objectives of this research is to obtain data about the consumption of contraceptive medicines in Kosovo, compare to other European countries with drug utilization studies and try to understand the rationale about the obtained results while also measuring progress towards the WHO Millennium Development Goals and Kosovo Health Sectorial Strategy 2017-2021.Regarding the contraceptive medicine consumption it is used the ATC classification of and the Defined Daily Doses per inhabitant per day (DID) as a numeric tool of the analysis. As for the perception of contraceptive dispensing in retail pharmacies are conducted interviews with pharmacists and for the prescription with doctors as part of the qualitative research with predefined questioners with open ended questions. There are analyzed all drugs of the G Group (Genitourinary system and sex hormones) in Kosovo from 2011 to 2015. From the medicines consumption data, it is seen that for the G-Group there is in general increasing trend of the total consumption in DID from 4.26 DID in 2011 to 10.52 DID in 2015. In the detailed analysis for the contraceptives subgroup G03A - Hormonal contraceptives for systemic use and G03D – Progestogens are the most consumed with 2.78 DID respectively 2.91 DID for the five year period 2011-2015.Kosovo is among the countries with very low contraception medicine consumption compared to other European and neighboring countries, which have much more consumption of this class of medicines as in Croatia with annual average of 36.12 DID, Montenegro 24.2 DID, Serbia 40.5 DID, Estonia 52.17 DID, Latvia 32.67 DID, Lithuania 28.72 DID. These data show the entire group G, however also the subgroup analysis show similar comparison. From the interviews with pharmacists and doctors it can be concluded that there is a low budget for providing and covering all the needs, there is lack of education for the benefits of the contraception use although the UNFPA has done a lot on this regard, but there are also a cultural, economic, and social factors for which Ministry of Health should make more awareness campaigns and fulfill the requirements from the health sectorial strategy

Supplementary data for article: Mehmeti, E.; Stanković, D. M.; Ortner, A.; Zavašnik, J.; Kalcher, K. Highly Selective Electrochemical Determination of Phlorizin Using Square Wave Voltammetry at a Boron-Doped Diamond Electrode. Food Analytical Methods 2017, 10 (11), 3747–3752. https://doi.org/10.1007/s12161-017-0935-x

Supplementary material for: [https://doi.org/10.1007/s12161-017-0935-x]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2531

Supplementary data for article: Mehmeti, E.; Stanković, D. M.; Chaiyo, S.; Zavasnik, J.; Žagar, K.; Kalcher, K. Wiring of Glucose Oxidase with Graphene Nanoribbons: An Electrochemical Third Generation Glucose Biosensor. Microchimica Acta 2017, 184 (4), 1127–1134. https://doi.org/10.1007/s00604-017-2115-5

Supplementary material for: [https://doi.org/10.1007/s00604-017-2115-5]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/2438

Supplementary data for article: Stanković, D. M.; Mehmeti, E.; Svorc, L.; Kalcher, K. Simple, Rapid and Sensitive Electrochemical Method for the Determination of the Triketone Herbicide Sulcotrione in River Water Using a Glassy Carbon Electrode. Electroanalysis 2015, 27 (7), 1587–1593. https://doi.org/10.1002/elan.201400729

Supporting information for: [https://doi.org/10.1002/elan.201400729]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1731

Supplementary data for the article: Kunpatee, K.; Chamsai, P.; Mehmeti, E.; Stankovic, D. M.; Ortner, A.; Kalcher, K.; Samphao, A. A Highly Sensitive Fenobucarb Electrochemical Sensor Based on Graphene Nanoribbons-Ionic Liquid-Cobalt Phthalocyanine Composites Modified on Screen-Printed Carbon Electrode Coupled with a Flow Injection Analysis. Journal of Electroanalytical Chemistry 2019, 855. https://doi.org/10.1016/j.jelechem.2019.113630

Supplementary material for: [https://doi.org/10.1016/j.jelechem.2019.113630]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3821

Determination of pyridoxine (vitamin B-6) in pharmaceuticals and urine samples using unmodified boron-doped diamond electrode

Pyridoxine (vitamin B-6, VB6) was detected in pharmaceutical preparation and human urine samples by employing differential pulse voltammetry (DPV) at unmodified boron doped electrode. In Britton-Robinson buffer solution (BRBS) at pH 6, VB6 provides well defined oxidation peak at around +1.05 V vs. Ag/AgCl (3 M KCl). The influence of most of the interferents present in real samples, supporting electrolyte and DPV parameters was investigated. A VB6 sensor with and linear range from 7 to 47 and a detection limit of 3.76 was obtain after optimization. Repeatability of the proposed procedure calculated after 7 measurements of 9 and 30 mu M of VB6 was 3.6 and 2.4%, respectively. Proposed methodology was successfully applied for the determination of VB6 in real samples, and from obtained results, it can be concluded that proposed analytical procedure can be an inexpensive alternative to the widely used separation methods. Prime Novelty statement: This work presents the quantification of vitamin B-6, using differential pulse voltammetry, with boron-doped diamond electrode. BDD electrode is, up to date, one of the best electrode materials, with extremely low background current and negligible passivation. The aim of this study was to develop method for vitamin B-6 determination in various matrices, as can be seen from the results, the obtained procedure shows good recovery values in tested samples and could be a satisfactory replacement to the separation methods and modified electrodes. (C) 2016 Elsevier B.V. All rights reserved.This is peer-reviewed version of the following article: Kuzmanović, D.; Khan, M.; Mehmeti, E.; Nazir, R.; Amaizah, N. R. R.; Stanković, D. Determination of Pyridoxine (Vitamin B-6) in Pharmaceuticals and Urine Samples Using Unmodified Boron-Doped Diamond Electrode. Diamond and Related Materials 2016, 64, 184–189. [https://doi.org/10.1016/j.diamond.2016.02.018

Supplementary data for the article: Kunpatee, K.; Chamsai, P.; Mehmeti, E.; Stankovic, D. M.; Ortner, A.; Kalcher, K.; Samphao, A. A Highly Sensitive Fenobucarb Electrochemical Sensor Based on Graphene Nanoribbons-Ionic Liquid-Cobalt Phthalocyanine Composites Modified on Screen-Printed Carbon Electrode Coupled with a Flow Injection Analysis. Journal of Electroanalytical Chemistry 2019, 855. https://doi.org/10.1016/j.jelechem.2019.113630

Supplementary material for: [https://doi.org/10.1016/j.jelechem.2019.113630]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3821

Comparative electrochemical study on the effects of heterogeneous carbon nanostructured-materials on the properties of screen-printed carbon electrodes towards Riboflavin determination

In this work, the influence of graphene nanoribbons (GNs), graphene nanoplatelets (GNPls), multi-walled carbon nanotubes (MWCNTs) and graphene oxide (GO) as a modifier on the properties of screen-printed carbon electrodes towards electrochemical determination of riboflavin (VB2) is investigated. Additionally, ionic liquid (IL, 1-Butyl-2,3-dimethylimidazolium tetra fluoroborate), iron(II) phthalocyanine (FePc) and Nafion were added into the modifier suspensions and further tested for their electro-catalytic effect. Their performance as modifier is compared to unmodified screen-printed carbon electrodes (SPCE). Unmodified screen-printed electrodes are printed in laboratory onto the ceramic substrate using carbon ink. Modified electrodes are prepared by drop-casting modifier suspension onto the active surface area of SPCE. The three-electrode system is used, consisted of a glass vessel equipped with the screen-printed carbon electrode as a working electrode (unmodified or modified), the reference electrode an Ag/AgCl electrode (3M KCl) and the auxiliary electrode a platinum wire. The studies are done using cyclic voltammetry (CV) in Britton-Robinson buffer solution (BRBS, pH 2.0) as a supporting electrolyte at scan rate of 50 mV/s. The preliminary results show that in comparison to modified screen-printed carbon electrodes, unmodified electrodes give increased current signals where the redox reaction of riboflavin occurs. Unmodified screen-printed electrodes usually give high responses due to the more hydrophilic surface and are very easy to handle, with excellent sensitivity and as low cost electro-analytical tools. Nevertheless, the results seem promising that the the modifier free sensor can be applied for the quick quantification of riboflavin