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Shemnsa A, Adane WD, Tessema M, Tesfaye E, Tesfaye G. Simultaneous Determination of Mineral Nutrients and Toxic Metals in M. stenopetala from Southern Ethiopia: A Comparative Study of Three Cultivating Areas Using MP-AES. J Anal Methods Chem 2024; 2024:8981995. [PMID: 38222894 PMCID: PMC10787013 DOI: 10.1155/2024/8981995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Revised: 12/10/2023] [Accepted: 12/29/2023] [Indexed: 01/16/2024]
Abstract
In this study, for the first time, the levels of thirteen micro- and macromineral nutrients in the leaves, seeds, and supportive soil of Moringa stenopetala (M. stenopetala) were simultaneously determined using microwave plasma atomic emission spectroscopy (MP-AES). The samples were collected during the arid season, in 2019 from the three main M. stenopetala growing areas in southern Ethiopia (Chano Mile Kebele, Nechisar Kebele, and Konso Special Woreda). A novel digestion method for leaf and seed samples was developed using an optimized acid mixture (2.5 : 0.75 : 0.5 of HNO3, HClO4, and H2O2) at 240°C for 2 hrs and 30 min, resulting in clear and colorless solutions. The method makes the digestion process more efficient by minimizing the reagent volume, reducing digestion temperature and time, and simplifying the overall procedure. The efficiency of the optimized procedure was validated by spiking experiments, and the percentage recovery ranged between 94 and 110%. Under optimized experimental conditions, higher concentrations of essential minerals (K, Na, Ca, and Mg) were observed in the plant leaf and seed samples from the three areas. In addition, significant amounts of trace elements (Fe, Mn, Zn, and Cu) were also found. Importantly, no traces of the toxic elements (Cd and Pb) were detected in any of the analyzed samples, suggesting that the leaves and seeds of M. stenopetala are valuable sources of both micro- and macromineral nutrients and are safe from toxic metals. From a dietary perspective, the seed contains almost comparable concentrations of minerals as the leaves. As a result, the seeds of M. stenopetala can serve as an alternative source of minerals and play a role in overcoming the current global food crisis, particularly in the dry season. Analysis of variance at a 95% confidence level revealed significant differences in the levels of all mineral nutrients between the three sample means except K, Ca, Co, and Cu. Generally, the developed method includes an innovative digestion procedure that minimizes reagent consumption, operates at lower temperatures, and requires shorter digestion times, thereby optimizing resource utilization and maintaining analytical accuracy. Notably, the absence of toxic elements in the MP-AES procedure highlights the safety and reliability of M. stenopetala leaves and seeds as valuable, contamination-free sources of essential nutrients.
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Affiliation(s)
- Ashenafi Shemnsa
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
| | | | - Merid Tessema
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia
| | - Endale Tesfaye
- Department of Chemistry, Gambella University, P.O. Box 126, Gambella, Ethiopia
| | - Gizaw Tesfaye
- Department of Chemistry, Fitche College of Teachers Education, P.O. Box 260, Fitche, Ethiopia
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Tesfaye E, Chandravanshi BS, Negash N, Tessema M. Electrochemical determination of zinc(II) using N 1-hydroxy-N 1,N 2-diphenylbenzamidine and multi-walled carbon nanotubes modified carbon paste electrode. Heliyon 2023; 9:e17346. [PMID: 37383216 PMCID: PMC10293732 DOI: 10.1016/j.heliyon.2023.e17346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 06/12/2023] [Accepted: 06/14/2023] [Indexed: 06/30/2023] Open
Abstract
In this study, a new carbon paste electrode modified with a laboratory-synthesized ligand, N1-hydroxy-N1,N2-diphenylbenzamidine (HDPBA) and multi-walled carbon nanotubes (MWCNTs) (HDPBA‒MWCNTs/CPE) has been developed. The modified electrode was applied for preconcentration and voltammetric determination of zinc ions (Zn(II)) by square wave anodic stripping voltammetry (SWASV). The preconcentration of Zn(II) on the electrode surface was performed in 0.1 M Brinton Robinson (B-R) buffer solution (pH 6) at an applied potential of -1.30 V versus Ag/AgCl for 120 s, followed by stripping in the positive potential scan of the SWASV after a quit time of 10 s. Under optimized experimental conditions, the proposed electrode exhibited a wider linear dynamic response for Zn(II) in a concentration range of 0.02-10.00 μM with a detection limit of 2.48 nM. This is due to the excellent metal-chelation property of the ligand, and the good conductivity and large surface area of MWCNTs which significantly improved the sensing performance of the nanocomposite modified electrode. The selectivity of the electrode was studied by evaluating the interference effects of various foreign ions on the peak current of Zn(II). The method exhibited high reproducibility with a relative standard deviation (RSD) of 3.1%. The present method was applied for the determination of zinc ions in water samples. The recovery values in the tested samples were found to be 98.50-106.0%, indicating a good accuracy of the proposed electrode. Furthermore, the electrochemical behavior of HDPBA in acetonitrile and aqueous solutions has been studied.
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Tesfaye G, Tessema M, Negash N. Electrochemical determination of vitamin B6 in pharmaceutical and energy drink samples. J Electrochem Sci Eng 2023. [DOI: 10.5599/jese.1674] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/05/2023] Open
Abstract
A simple and low-cost electrochemical sensor based on poly(phenylalanine) and functionnalized multi-walled carbon nanotubes (F-MWCNTs) modified glassy carbon electrode (GCE) was developed for the determination of vitamin B6 (VB6). The surface morphology of modified glassy carbon electrodes was investigated with scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). The electrocatalytic activities of the bare and modified electrodes were investigated in the presence of ferri-ferrocyanide redox couple using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The exchange current density (jo = 2462 µA cm-2) and electron transfer rate constant (ko = 0.002 cm s−1) were calculated using 5 mM K3[Fe(CN)6]. The electrochemical activity of poly(phenylalanine)/F-MWCNT/GCE towards VB6 oxidation was investigated using CV. Parameters including the number of electrons transferred (n = 2), number of protons transferred (H+ = 2), electron transfer coefficient (α = 0.51) and surface concentration of VB6 (G = 0.24 nmol cm−2) were calculated. At the optimal experimental conditions, the oxidation peak current of VB6 measured by square wave voltammetry (SWV) was found proportional to its concentration in two linear ranges of 0.5 to 20 µM and 20 to 200 µM with a low detection limit (LOD) of 0.038 µM and limit of quantification (LOQ) of 0.125 µM. Finally, the sensor was successfully used to determine VB6 in soft drink and pharmaceutical formulation samples.
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Tesfaye E, Chandravanshi BS, Negash N, Tessema M. Development of a new electrochemical method for the determination of copper(ii) at trace levels in environmental and food samples. RSC Adv 2022; 12:35367-35382. [PMID: 36540237 PMCID: PMC9742860 DOI: 10.1039/d2ra06941e] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 12/03/2022] [Indexed: 09/10/2023] Open
Abstract
This paper presents the fabrication of a new modified carbon paste electrode (CPE) with N 1-hydroxy-N 1,N 2-diphenylbenzamidine (HDPBA) and functionalized multi-walled carbon nanotubes (MWCNTs) (HDPBA-MWCNTs/CPE) for highly sensitive and selective determination of Cu(ii) using the square wave anodic stripping voltammetry (SWASV) technique. The fabricated electrode was characterized using various spectroscopic techniques to study its morphological, structural, and electrochemical properties. The accumulation of Cu(ii) on the surface of HDPBA-MWCNTs/CPE was done in 0.1 M ammonium chloride (NH4Cl, pH 5) solution at an applied potential of -0.70 V versus Ag/AgCl for 180 s, followed by electrochemical stripping in the positive scan of the voltammetry after a resting time of 10 s. The developed HDPBA-MWCNTs/CPE was found to be highly selective, sensitive and reproducible. At optimal conditions of the experiment, the proposed method exhibited a very low limit of detection (0.0048 nM Cu(ii)), a wide linear dynamic range (0.00007-1.5000 μM Cu(ii)), and good reproducibility with relative standard deviation (RSD) value of 3.7%. The effect of various foreign ions on the voltammetric response of Cu(ii) was investigated and the electrode was found to be highly selective to Cu(ii). The practical applicability of the proposed HDPBA-MWCNTs/CPE was studied by applying the electrode for the quantification of Cu(ii) contents in environmental water (wastewater and tap water), soft drink (Fanta and Sprite), and food supplement (commercially available multi-mineral/vitamin tablets) samples. The present method was validated with atomic absorption spectrometry (AAS). The results found from the two methods are in good agreement with a 95% confidence level.
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Affiliation(s)
- Endale Tesfaye
- Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia
| | - Bhagwan Singh Chandravanshi
- Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia
| | - Negussie Negash
- Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia
| | - Merid Tessema
- Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University P.O. Box 1176 Addis Ababa Ethiopia
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Adane WD, Chandravanshi BS, Tessema M. A simple, ultrasensitive and cost-effective electrochemical sensor for the determination of ciprofloxacin in various types of samples. Sensing and Bio-Sensing Research 2022. [DOI: 10.1016/j.sbsr.2022.100547] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
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Tesfaye E, Chandravanshi BS, Negash N, Tessema M. A new modified carbon paste electrode using N1-hydroxy-N1,N2-diphenylbenzamidine for the square wave anodic stripping voltammetric determination of Pb(II) in environmental samples. Sensing and Bio-Sensing Research 2022. [DOI: 10.1016/j.sbsr.2022.100520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Tesfaye G, Negash N, Tessema M. Sensitive and selective determination of vitamin B2 in non-alcoholic beverage and milk samples at poly (glutamic acid)/zinc oxide nanoparticles modified carbon paste electrode. BMC Chem 2022; 16:69. [PMID: 36117181 PMCID: PMC9482753 DOI: 10.1186/s13065-022-00863-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 09/06/2022] [Indexed: 11/10/2022] Open
Abstract
Abstract
Background
The deficiency of vitamin B2 can lead to many health problems. Therefore, it is necessary to develop a sensitive, selective and fast method for the determination of vitamin B2 in food samples. In this work, a sensitive, selective and low-cost electrochemical sensor was developed using poly (glutamic acid) and Zinc oxide nanoparticles (ZnO NPs) for vitamin B2 in non-alcoholic beverage and milk samples.
Methods
The modification of the electrode surface was carried out by electropolymerization of glutamic acid on ZnO NPs–carbon paste electrode (ZnO NPS–CPE). The prepared electrodes were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM) and X-Ray diffraction (XRD). CV and square wave voltammetry (SWV) were used to investigate the electrochemical behavior of vitamin B2 at the modified electrode. The effect of various parameters such as amount of ZnO NPs, polymerization cycle, concentration of the monomer, pH, scan rate and accumulation time were optimized to obtain maximum sensitivity at the modified electrode.
Results
The developed sensor showed high electrocatalytic activity towards vitamin B2. Under the optimized conditions, the developed sensor showed a linear response in the range 0.005–10 µM with a low detection limit of (LOD) 0.0007 ± 0.00001 µM and high sensitivity of 21.53 µA/µM.
Conclusions
A reproducible, repeatable, stable and selective sensor was successfully applied for the quantification of vitamin B2 in beverage and milk samples with acceptable recoveries in the range of 88–101%.
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Tesfaye G, Negash N, Hailu T, Tessema M. Simultaneous Determination of Gallic acid and Folic acid in Fruit Juice Samples Using Square Wave Voltammetry at Electrochemically Pretreated Carbon Paste Electrode. ELECTROANAL 2022. [DOI: 10.1002/elan.202100645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Gizaw Tesfaye
- Addis Ababa University College of Natural Sciences ETHIOPIA
| | | | - Tesfu Hailu
- Addis Ababa Science and Technology University ETHIOPIA
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Tesfaye E, Singh Chandravanshi B, Hailu T, Negash N, Tessema M. Square Wave Anodic Stripping Voltammetric Determination of Hg(II) with N
1
‐hydroxy‐N
1
,N
2
‐diphenylbenzamidine Modified Carbon Paste Electrode. ELECTROANAL 2022. [DOI: 10.1002/elan.202100468] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Endale Tesfaye
- Department of Chemistry College of Natural and Computational Sciences Addis Ababa University P.O. Box 1176 1176 Addis Ababa Ethiopia
| | - Bhagwan Singh Chandravanshi
- Department of Chemistry College of Natural and Computational Sciences Addis Ababa University P.O. Box 1176 1176 Addis Ababa Ethiopia
| | - Tesfu Hailu
- Department of Chemistry College of Natural and Computational Sciences Addis Ababa University P.O. Box 1176 1176 Addis Ababa Ethiopia
| | - Negussie Negash
- Department of Chemistry College of Natural and Computational Sciences Addis Ababa University P.O. Box 1176 1176 Addis Ababa Ethiopia
| | - Merid Tessema
- Department of Chemistry College of Natural and Computational Sciences Addis Ababa University P.O. Box 1176 1176 Addis Ababa Ethiopia
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Tesfaye E, Singh Chandravanshi B, Negash N, Tessema M. A Novel Carbon Paste Electrode Modified with N 1-Hydroxy-N 1,N 2-Diphenylbenzamidine for the Electrochemical Determination of Cadmium(II) in Environmental Samples. J Anal Methods Chem 2022; 2022:3426575. [PMID: 36248055 PMCID: PMC9553701 DOI: 10.1155/2022/3426575] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/01/2022] [Accepted: 08/31/2022] [Indexed: 05/14/2023]
Abstract
The present study introduces a novel electrode for rapid, highly sensitive, and selective electrochemical sensor for cadmium(II) using 5% N1-hydroxy-N1,N2-diphenylbenzamidine (HDPBA) modified carbon paste electrode (CPE) (HDPBA‒CPE). Surface characterizations and structural analysis of the proposed HDPBA‒CPE were performed using several analytical techniques. The voltammetric measurements of Cd(II) were conducted by cyclic voltammetry (CV) and square wave anodic stripping voltammetry (SWASV). Several experimental conditions such as composition and pH of buffer solutions, HDPBA composition, accumulation potential and time, and other voltammetric conditions were optimized. Cd(II) was preconcentrated on the modified electrode surface for 270 s using Britton Robinson (B-R) buffer (0.1 M, pH 4) at -1.0 V versus Ag/AgCl, followed by electrochemical oxidation of the accumulated Cd(II) in the positive scan of SWASV after a quiet time of 10 s. Under optimized parameters, the proposed method showed a linear range of 0.3-100 nM Cd(II) with a detection limit of 0.032 nM. The fabricated HDPBA-modified carbon paste electrode exhibited excellent sensitivity, selectivity, stability, and reproducibility (with RSD of 3.8%). The developed HDPBA‒CPE was used for the quantification of Cd(II) in tobacco and environmental water samples, and it was found to be applicable for the determination of different types of real samples.
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Affiliation(s)
- Endale Tesfaye
- Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
| | - Bhagwan Singh Chandravanshi
- Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
| | - Negussie Negash
- Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
| | - Merid Tessema
- Department of Chemistry, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
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Tesfaye G, Hailu T, Ele E, Negash N, Tessema M. Square wave voltammetric determination of quercetin in wine and fruit juice samples at poly (safranine O) modified glassy carbon electrode. Sensing and Bio-Sensing Research 2021. [DOI: 10.1016/j.sbsr.2021.100466] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Tefera M, Tessema M, Admassie S, Ward M, Phelane L, Iwuoha EI, Baker PG. Electrochemical application of cobalt nanoparticles-polypyrrole composite modified electrode for the determination of phoxim. Anal Chim Acta X 2021; 9:100077. [PMID: 34622198 PMCID: PMC8482437 DOI: 10.1016/j.acax.2021.100077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 09/17/2021] [Accepted: 09/18/2021] [Indexed: 11/10/2022] Open
Abstract
In this study, cobalt nanoparticles (CoNPs) were synthesized and cobalt nanoparticles modified glassy carbon electrode (CoNPs/GCE) was prepared by drop coating the nanoparticles on glassy carbon electrode. After preparing polypyrrole modified glassy carbon electrode (PPy/GCE) using electropolymerization of pyrrole in LiClO4 solution, cobalt nanoparticles-polypyrrole composite modified glassy carbon electrode (CoNPs/PPy/GCE) was fabricated by drop coating the CoNPs on the PPy/GCE. Different characterization techniques such as scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, FTIR spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry were used to study the morphological structure and electrochemical behavior of the sensors. The results demonstrated that PPy chains interacted with CoNPs through donor-acceptor bonds. Among all the electrodes, CoNPs/PPy/GCE exhibited highest electroactive surface area and lowest electron transfer resistance towards phoxim. Under the optimal conditions, the sensor showed linear relationship between the reduction peak current and the concentration of phoxim in the range of 0.025 μM-12 μM with the detection limit as 4.5 nM. Besides, the composite electrode demonstrated excellent reproducibility, good stability and selectivity towards the possible interfering substances. All of these properties made CoNPs/PPy/GCE a suitable electrochemical sensor for the electrochemical determination of phoxim in water samples using square wave voltammetry.
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Affiliation(s)
- Molla Tefera
- Department of Chemistry, University of Gondar, P. O. Box 196, Gondar, Ethiopia
| | - Merid Tessema
- Department of Chemistry, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
| | - Shimelis Admassie
- Department of Chemistry, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
| | - Meryck Ward
- Sensor Lab, Department of Chemistry, University of the Western Cape, Private Bag X17, Robert Sobukwe Drive, Bellville, 7535, South Africa
| | - Lisebo Phelane
- Sensor Lab, Department of Chemistry, University of the Western Cape, Private Bag X17, Robert Sobukwe Drive, Bellville, 7535, South Africa
| | - Emmanuel I. Iwuoha
- Sensor Lab, Department of Chemistry, University of the Western Cape, Private Bag X17, Robert Sobukwe Drive, Bellville, 7535, South Africa
| | - Priscilla G.L. Baker
- Sensor Lab, Department of Chemistry, University of the Western Cape, Private Bag X17, Robert Sobukwe Drive, Bellville, 7535, South Africa
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Tefera M, Tessema M, Admassie S, Guadie A. Electrochemical determination of endosulfan in vegetable samples using mercury film modified glassy carbon electrode. Sensing and Bio-Sensing Research 2021. [DOI: 10.1016/j.sbsr.2021.100431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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Tefera M, Tessema M, Admassie S, Wubet W. Voltammetric determination of uric acid using multiwall carbon nanotubes coated-poly(4-amino-3-hydroxy naphthalene sulfonic acid) modified glassy carbon electrode. Heliyon 2021; 7:e07575. [PMID: 34337185 PMCID: PMC8318863 DOI: 10.1016/j.heliyon.2021.e07575] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2021] [Revised: 04/24/2021] [Accepted: 07/12/2021] [Indexed: 12/03/2022] Open
Abstract
In this study, an electrochemical sensor based multiwalled carbon nanotubes (MWCNTs)-poly (4-amino-3-hydroxy naphthalene sulfonic acid) modified glassy carbon electrode (MWCNTs/poly (AHNSA)/GCE) was developed for the determination of uric acid (UA). The composite electrode was prepared first by electropolymerization of the monomer (AHNSA) on GCE using cyclic voltammetry within the potential range of -0.8 V to +2.0 V vs Ag/AgCl for 15 cycles followed by drop coating of MWCNTs solution on the surface of poly (AHNSA)/GCE. Under optimal conditions, MWCNTs/poly (AHNSA)/GCE showed a linear current response with UA concentrations in the range of 1 × 10-6 to 1 × 10-4 M with R2 = 0.9972. The sensor exhibited low detection limit with a value of 0.024 μM. The sensors have been applied to successfully quantify UA in urine samples.
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Affiliation(s)
- Molla Tefera
- Department of Chemistry, University of Gondar, P. O. Box 196, Gondar, Ethiopia
| | - Merid Tessema
- Department of Chemistry, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
| | - Shimelis Admassie
- Department of Chemistry, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia
| | - Walelign Wubet
- Department of Chemistry, University of Gondar, P. O. Box 196, Gondar, Ethiopia
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Alemayehu D, Chandravanshi BSC, Hailu T, Tessema M. Square wave anodic stripping voltammetric determination of Hg(II) with N-p- chlorophenylcinnamohydroxamic acid modified carbon paste electrode. B CHEM SOC ETHIOPIA 2020. [DOI: 10.4314/bcse.v34i1.3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
A new method has been developed for the electrochemical determination of Hg(II) with N-p-chlorophenylcinnamohydroxamic acid (CPCHA) modified carbon paste electrode by square wave anodic stripping voltammetry (SWASV). Hg(II) was accumulated on the electrode surface by the formation of the complex in an open circuit and the resulting surface was characterized by electrochemical reduction and stripping. The optimum voltammetric response was observed using a carbon paste composition of 7.5% (w/w) CPCHA and preconcentration time of 210 s in 0.1 M sodium acetate at pH 8 followed by electrochemical SWASV in 0.3 M NH4Cl solution at pH 4 at a reduction potential of -0.6 V. The voltammetric signals were linear in the range of 1-25 µM Hg(II) with a detection limit of 12.9 nM. The voltammetric response for six replicate measurements of 15 µM Hg(II) was reproduced with 3.8% relative standard deviation (RSD). Many coexisting metal ions had little or no effect on the determination of Hg(II). Five spiked samples of water were evaluated by using the developed method giving recoveries of Hg(II) in the range 98-105%.
Bull. Chem. Soc. Ethiop. 2020, 34(1), 25-39.
DOI: https://dx.doi.org/10.4314/bcse.v34i1.3
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Mekassa B, G. L. Baker P, S. Chandravanshi B, Tessema M. Sensitive electrochemical determination of ethambutol in pharmaceutical formulation and human urine at nickel nanoparticles/electrochemically reduced graphene oxide modified electrode. B CHEM SOC ETHIOPIA 2019. [DOI: 10.4314/bcse.v33i2.3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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L. Hailu S, U. Nair B, R. Abshiro M, Diaz I, Tessema M. Computational studies on heterogenization of homogeneous catalyst of iron(III), nickel(II) and copper(II) N,N′-disalicylidene-1,2-phenylenediamine complex. B CHEM SOC ETHIOPIA 2019. [DOI: 10.4314/bcse.v33i1.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Mekassa B, Tessema M, Chandravanshi BS, Baker PG, Muya FN. Sensitive electrochemical determination of epinephrine at poly(L-aspartic acid)/electro-chemically reduced graphene oxide modified electrode by square wave voltammetry in pharmaceutics. J Electroanal Chem (Lausanne) 2017. [DOI: 10.1016/j.jelechem.2017.11.045] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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Mekassa B, Tessema M, Chandravanshi BS. Simultaneous determination of caffeine and theophylline using square wave voltammetry at poly( l -aspartic acid)/functionalized multi-walled carbon nanotubes composite modified electrode. Sensing and Bio-Sensing Research 2017. [DOI: 10.1016/j.sbsr.2017.11.002] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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Hailu SL, Nair BU, Redi-Abshiro M, Aravindhan R, Diaz I, Tessema M. Experimental and computational studies on zeolite-Y encapsulated iron(iii) and nickel(ii) complexes containing mixed-ligands of 2,2′-bipyridine and 1,10-phenanthroline. RSC Adv 2015. [DOI: 10.1039/c5ra14954a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mixed ligand complexes of 2,2′-bipyridine and 1,10-phenanthroline with iron(iii) and nickel(ii) have been encapsulated into a zeolite cage by the reaction of zeolite exchanged metal ion with flexible ligands.
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Affiliation(s)
- Solomon Legese Hailu
- Chemical Laboratory
- CSIR-Central Leather Research Institute
- Chennai 600 020
- India
- Department of Chemistry
| | | | | | - Rathinam Aravindhan
- Chemical Laboratory
- CSIR-Central Leather Research Institute
- Chennai 600 020
- India
| | - Isabel Diaz
- Department of Chemistry
- Addis Ababa University
- Addis Ababa
- Ethiopia
- Instituto de Catálisis y Petroleoquímica
| | - Merid Tessema
- Department of Chemistry
- Addis Ababa University
- Addis Ababa
- Ethiopia
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Degefu H, Amare M, Tessema M, Admassie S. Lignin modified glassy carbon electrode for the electrochemical determination of histamine in human urine and wine samples. Electrochim Acta 2014. [DOI: 10.1016/j.electacta.2013.12.133] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Negash N, Alemu H, Tessema M. Flow Injection Amperometric Determination of Phenol and Chlorophenols at Single Wall Carbon Nanotube Modified Glassy Carbon Electrode. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/ajac.2014.53023] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Reed MD, Tellez CS, Grimes MJ, Picchi MA, Tessema M, Cheng YS, March TH, Kuehl PJ, Belinsky SA. Aerosolised 5-azacytidine suppresses tumour growth and reprogrammes the epigenome in an orthotopic lung cancer model. Br J Cancer 2013; 109:1775-81. [PMID: 24045660 PMCID: PMC3790193 DOI: 10.1038/bjc.2013.575] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 08/21/2013] [Accepted: 08/28/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Epigenetic silencing by promoter methylation and chromatin remodelling affects hundreds of genes and is a causal event for lung cancer. Treatment of patients with low doses of the demethylating agent 5-azacytidine in combination with the histone deacetylase inhibitor entinostat has yielded clinical responses. The subcutaneous dosing route for consecutive days and reduced bioavailability of 5-azacytidine because of inactivation by cytidine deaminase may limit the expansion of epigenetic therapy into Phase III trials. To mitigate these barriers, an aerosol of 5-azacytidine was generated and characterised. METHODS The effect of aerosol vs systemic delivery of 5-azacytidine on tumour burden and molecular response of engrafted lung tumours in the nude rat was compared. RESULTS Pharmacokinetics revealed major improvement in the half-life of 5-azacytidine in lung tissue with aerosol delivery. Aerosolised 5-azacytidine significantly reduced lung tumour burden and induced global demethylation of the epigenome at one-third of the comparable effective systemic dose. High commonality for demethylation of genes was seen in tumours sampled throughout lung lobes and across treated animals receiving the aerosolised drug. CONCLUSION Collectively, these findings show that aerosolised 5-azacytidine targets the lung, effectively reprogrammes the epigenome of tumours, and is a promising approach to combine with other drugs for treating lung cancer.
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Affiliation(s)
- M D Reed
- Lung Cancer Program, Lovelace Respiratory Research Institute, 2425 Ridgecrest Drive SE, Albuquerque, NM 87108, USA
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Geto A, Amare M, Tessema M, Admassie S. Polymer-modified glassy carbon electrode for the electrochemical detection of quinine in human urine and pharmaceutical formulations. Anal Bioanal Chem 2012; 404:525-30. [PMID: 22699238 DOI: 10.1007/s00216-012-6171-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2012] [Revised: 05/28/2012] [Accepted: 05/30/2012] [Indexed: 11/28/2022]
Abstract
Glassy carbon electrode was modified by electropolymerization of 4-amino-3-hydroxynaphthalene sulfonic acid. Cyclic voltammetric study of quinine showed higher current response at the modified electrode compared to the bare and activated glassy carbon electrodes in pH 7.0 phosphate buffer solution. Under optimized conditions, a calibration curve was obtained by square wave voltammetry at the modified electrode. The linear relationship between the peak current and the concentration of quinine in the range of 1.0 × 10(-7) to 1.0 × 10(-5) M was I (pa) (in microamperes) = 6.26C (in micromolars) + 0.2997 (R (2) = 0.999). The detection limit calculated (S/N = 3) was 1.42 × 10(-8) M, which is much lower than similar reports. The method was successfully applied for the determination of quinine in spiked human urine, and pharmaceutical formulations and recovery values >90 % were obtained.
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Affiliation(s)
- Alemnew Geto
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.
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Geto A, Amare M, Tessema M, Admassie S. Voltammetric Determination of Nicotine at Poly(4-Amino-3-Hydroxynaphthalene Sulfonic Acid)-Modified Glassy Carbon Electrode. ELECTROANAL 2012. [DOI: 10.1002/elan.201100653] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Mehretie S, Losada J, Tessema M, Admassie S, Solomon T, Perez-Pariente J, Díaz I. Stripping voltammetric determination of pyridine-2-aldoxime methochloride at the iron(iii) doped zeolite modified glassy carbon electrode. Analyst 2012; 137:5625-31. [DOI: 10.1039/c2an35851d] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Tessema M, Klinge DM, Yingling CM, Do K, Van Neste L, Belinsky SA. Re-expression of CXCL14, a common target for epigenetic silencing in lung cancer, induces tumor necrosis. Oncogene 2010; 29:5159-70. [PMID: 20562917 PMCID: PMC2940978 DOI: 10.1038/onc.2010.255] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Chemokines are important regulators of directional cell migration and tumor metastasis. A genome-wide transcriptome array designed to uncover novel genes silenced by methylation in lung cancer identified the CXC-subfamily of chemokines. Expression of eleven of the sixteen known human CXC-chemokines was increased in lung adenocarcinoma cell lines after treatment with 5-aza-2deoxycytidine (DAC). Tumor-specific methylation leading to silencing of CXCL5, 12 and 14 was found in over 75% of primary lung adenocarcinomas and DAC treatment restored expression of each silenced gene. Forced expression of CXCL14 in H23 cells where this gene is silenced by methylation increased cell death in vitro and dramatically reduced in vivo growth of lung tumor xenografts through necrosis of up to 90% of the tumor mass. CXCL14 re-expression had a profound effect on the genome altering the transcription of over 1,000 genes, including increased expression of 30 cell cycle inhibitor and pro-apoptosis genes. In addition, CXCL14 methylation in sputum from asymptomatic early stage lung cancer cases was associated with a 2.9-fold elevated risk for this disease compared to controls, substantiating its potential as a biomarker for early detection of lung cancer. Together these findings identify CXCL14 as an important tumor suppressor gene epigenetically silenced during lung carcinogenesis.
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Affiliation(s)
- M Tessema
- Lung Cancer Program, Lovelace Respiratory Research Institute, Albuquerque, NM, USA
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Aklilu M, Tessema M, Redi-Abshiro M. Indirect voltammetric determination of caffeine content in coffee using 1,4-benzoquinone modified carbon paste electrode. Talanta 2008; 76:742-6. [DOI: 10.1016/j.talanta.2008.04.042] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2008] [Revised: 04/08/2008] [Accepted: 04/11/2008] [Indexed: 10/22/2022]
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Tessema M, Länger F, Bock O, Seltsam A, Hasemeier B, Kreipe H, Lehmann U. Reduced expression of H19 and IGF-2 in chronic and acute leukemia is independent of the imprinting status. Pathol Res Pract 2004. [DOI: 10.1016/s0344-0338(04)80526-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Länger F, Stickel J, Tessema M, Metzig K, Kreipe H, Lehmann U. The delta-like (Dlk) protein is expressed in a wide variety of chronic and acute myeloid malignancies and also in normal bone marrow trephines. Pathol Res Pract 2004. [DOI: 10.1016/s0344-0338(04)80525-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Tessema M, Länger F, Dingemann J, Ganser A, Kreipe H, Lehmann U. Aberrant methylation and impaired expression of the p15(INK4b) cell cycle regulatory gene in chronic myelomonocytic leukemia (CMML). Leukemia 2003; 17:910-8. [PMID: 12750705 DOI: 10.1038/sj.leu.2402891] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2002] [Accepted: 12/20/2002] [Indexed: 12/14/2022]
Abstract
The important cell cycle regulatory gene p15(INK4b) has been shown to be inactivated in acute myeloid leukemia and myelodysplastic syndrome. Little is known about the expression and epigenetic modification of this gene in chronic myelomonocytic leukemia (CMML) that belongs to the myelodysplastic/myeloproliferative disorders (MDS/MPD) with a high proportion of blastic transformation. Analysis of bone marrow trephines in a series of 33 CMML cases showed an aberrant p15(INK4b) gene methylation in up to 58% of cases. Methylation was analyzed employing different methylation-specific PCR and genomic sequencing protocols. It turned out to be spread over a broad area of the 5' region and exhibited substantial heterogeneity between cases and even in individual patients. The degree of aberrant methylation was correlated with a reduced mRNA as well as reduced protein expression, and was associated with a higher expression of DNA methyltransferase DNMT 3A. We conclude that aberrant gene methylation is a frequent event in CMML that might contribute to the pathogenesis of this MDS/MPD.
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Affiliation(s)
- M Tessema
- 1Institute of Pathology, Medizinische Hochschule Hannover, Carl-Neuberg-Street 1, Hannover, Germany
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Tessema M, Bock O, Kröber S, Büsche G, Lugli A, Bock O, Berndt A, Huss R, Schmitt-Gräff A. Bone Marrow, Abstract 262–270, Symposium. Pathol Res Pract 2003. [DOI: 10.1078/0344-0338-00405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Tessema M, Csöregi E, Ruzgas T, Kenausis G, Solomon T, Gorton L. Oligosaccharide Dehydrogenase-Modified Graphite Electrodes for the Amperometric Determination of Sugars in a Flow Injection System. Anal Chem 1997; 69:4039-44. [DOI: 10.1021/ac970127f] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Merid Tessema
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Department of Analytical Chemistry, University of Lund, P.O. Box 124, SE-221 00, Lund, Sweden, Enzyme Chemistry Laboratory, Institute of Biochemistry, Mokslininku 12, LT-2600 Vilnius, Lithuania, and Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712-1062
| | - Elisabeth Csöregi
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Department of Analytical Chemistry, University of Lund, P.O. Box 124, SE-221 00, Lund, Sweden, Enzyme Chemistry Laboratory, Institute of Biochemistry, Mokslininku 12, LT-2600 Vilnius, Lithuania, and Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712-1062
| | - Tautgirdas Ruzgas
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Department of Analytical Chemistry, University of Lund, P.O. Box 124, SE-221 00, Lund, Sweden, Enzyme Chemistry Laboratory, Institute of Biochemistry, Mokslininku 12, LT-2600 Vilnius, Lithuania, and Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712-1062
| | - Gregg Kenausis
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Department of Analytical Chemistry, University of Lund, P.O. Box 124, SE-221 00, Lund, Sweden, Enzyme Chemistry Laboratory, Institute of Biochemistry, Mokslininku 12, LT-2600 Vilnius, Lithuania, and Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712-1062
| | - Theodros Solomon
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Department of Analytical Chemistry, University of Lund, P.O. Box 124, SE-221 00, Lund, Sweden, Enzyme Chemistry Laboratory, Institute of Biochemistry, Mokslininku 12, LT-2600 Vilnius, Lithuania, and Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712-1062
| | - Lo Gorton
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Department of Analytical Chemistry, University of Lund, P.O. Box 124, SE-221 00, Lund, Sweden, Enzyme Chemistry Laboratory, Institute of Biochemistry, Mokslininku 12, LT-2600 Vilnius, Lithuania, and Department of Chemical Engineering, The University of Texas at Austin, Austin, Texas 78712-1062
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Belay A, Ruzgas T, Csöregi E, Moges G, Tessema M, Solomon T, Gorton L. LC−Biosensor System for the Determination of the Neurotoxin β-N-Oxalyl-l-α,β-diaminopropionic Acid. Anal Chem 1997; 69:3471-5. [DOI: 10.1021/ac961098w] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Abebaw Belay
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Institute of Biochemistry, Mokslininku 12, 2600 Vilnius, Lithuania, and Department of Analytical Chemistry, University of Lund, P.O. Box 124, S-221 00, Lund, Sweden
| | - Tautgirdas Ruzgas
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Institute of Biochemistry, Mokslininku 12, 2600 Vilnius, Lithuania, and Department of Analytical Chemistry, University of Lund, P.O. Box 124, S-221 00, Lund, Sweden
| | - Elisabeth Csöregi
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Institute of Biochemistry, Mokslininku 12, 2600 Vilnius, Lithuania, and Department of Analytical Chemistry, University of Lund, P.O. Box 124, S-221 00, Lund, Sweden
| | - Ghirma Moges
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Institute of Biochemistry, Mokslininku 12, 2600 Vilnius, Lithuania, and Department of Analytical Chemistry, University of Lund, P.O. Box 124, S-221 00, Lund, Sweden
| | - Merid Tessema
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Institute of Biochemistry, Mokslininku 12, 2600 Vilnius, Lithuania, and Department of Analytical Chemistry, University of Lund, P.O. Box 124, S-221 00, Lund, Sweden
| | - Theodros Solomon
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Institute of Biochemistry, Mokslininku 12, 2600 Vilnius, Lithuania, and Department of Analytical Chemistry, University of Lund, P.O. Box 124, S-221 00, Lund, Sweden
| | - Lo Gorton
- Department of Chemistry, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia, Institute of Biochemistry, Mokslininku 12, 2600 Vilnius, Lithuania, and Department of Analytical Chemistry, University of Lund, P.O. Box 124, S-221 00, Lund, Sweden
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Larsson T, Elmgren M, Lindquist SE, Tessema M, Gorton L, Henriksson G. Electron transfer between cellobiose dehydrogenase and graphite electrodes. Anal Chim Acta 1996. [DOI: 10.1016/0003-2670(96)00136-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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