| 1. |
- Alpeeva, IS, et al.
(författare)
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Palm tree peroxidase-based biosensor with unique characteristics for hydrogen peroxide monitoring
- 2005
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Ingår i: Biosensors & Bioelectronics. - : Elsevier BV. - 1873-4235 .- 0956-5663. ; 21:5, s. 742-748
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Tidskriftsartikel (refereegranskat)abstract
- Three amperometric enzyme electrodes have been constructed by adsorbing anionic royal palm tree peroxidase (RPTP), anionic sweet potato peroxidase (SPP), or cationic horseradish peroxidase (HRP-C) on spectroscopic graphite electrodes. The resulting H2O2-sensitive biosensors were characterized both in a flow injection system and in batch mode to evaluate their main bioelectrochemical parameters, such as pH dependency,I-max, K-M(app), detection limit, linear range, operational and storage stability. The obtained results showed a distinctly different behavior for the plant peroxidase electrodes, demonstrating uniquely superior characteristics of the RPTP-based sensors. The broader linear range observed for the RPTP-based biosensor is explained by a high stability of this enzyme in presence of H2O2. The higher storage and operational stability of RPTP-based biosensor as well as its capability to measure hydrogen peroxide under acidic conditions connect with an extremely high thermal and pH-stability of RPTP.
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| 2. |
- Aquilante, Laura, et al.
(författare)
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Determination of biogenic amines by using amperometric biosensors based on grass PEA amine oxidase and OAT polyamine oxidase
- 2020
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Ingår i: Studia Universitatis Babes-Bolyai Chemia. - : Babes-Bolyai University. - 1224-7154 .- 2065-9520. ; 65:3, s. 9-21
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Tidskriftsartikel (refereegranskat)abstract
- Grass pea amine oxidase (GPAO) and oat polyamine oxidase (OPAO) were immobilized along with horseradish peroxidase (HRP) and an Os-redox polymer (Os-RP) onto the surface of a graphite electrode by crosslinking with poly(ethylenglycol) diglycidyl ether. The resulted reagentless amperometric biosensors were inserted in a flow injection setup and used as electrochemical detectors for the biogenic amines (BA) detection. Both biosensors were operated at low applied potential (-50 mV vs. Ag/AgCl, KCl0.1M) where electrochemical interferences are minimal. The quantification of ten BA (tyramine, putrescine, cadaverine, histamine, cystamine, phenylethylamine, agmatine, tryptamine, spermine, and spermidine) either individual or in mixture (after a preliminary separation by using cation exchange chromatography) was reported. G/(Os-RP)-HRP-GPAO biosensor detected all ten BA, while G/(Os-RP)-HRP-OPAO biosensor detected only spermine and spermidine. Finally, a simple and low-cost method for free and acetylated polyamines determination in human urine samples, by using the highly selective G/(Os-RP)-HRP-OPAO biosensor, was proposed.
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| 3. |
- LI, Chao, et al.
(författare)
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Fresh banana pseudo-stems as a tropical lignocellulosic feedstock for methane production
- 2016
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Ingår i: Energy, Sustainability and Society. - : Springer Science and Business Media LLC. - 2192-0567. ; 6:1, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- The banana pseudo-stem is a low-lignin-content lignocellulosic biomass that can be used for methane production. In recent years, anaerobic digestion (AD) of dried banana stems for methane production has attracted considerable attention. However, there is limited information regarding methane production from the fresh banana pseudo-stem. The direct usability of fresh banana stems as a resource for renewable energy production through AD is a called upon prerequisite for an improved waste management system culminating in a sustainable as well as socioeconomic development of local banana-producing communities.
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| 4. |
- Liu, Gangjin, et al.
(författare)
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Impact of atmospheric pressure variations on aerobic biodegradation test
- 2023
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Ingår i: Waste Management and Research. - 0734-242X. ; 41:10, s. 1559-1569
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Tidskriftsartikel (refereegranskat)abstract
- Biodegradation rate is an important index to evaluate the environmental risk of chemicals, which is usually determined by measuring oxygen consumption through respirometer in a biodegradation test. However, atmospheric pressure variations affect reactor oxygen concentration and oxygen volume recorded by respirometer in biodegradation test, and the parameters of reactor volume and test material amount amplify its effect. Atmospheric pressure variation >1 kPa could introduce >20% underestimation in biodegradation rate when a small amount of test material (0.04–0.2 g per 100 g of inoculum) and high reactor volume (2–4 L) were used according to the international standards. A 5 kPa drop in atmospheric pressure leads to a 6% decrease in headspace oxygen concentration in the reactor, which could subsequently inhibit biodegradation microbials and decrease the biodegradation rate by 30%. Moreover, the biodegradation process (oxygen consumption rate) could be accelerated/delayed several times by atmospheric pressure variations compared to the process without variations when the oxygen consumption rate was <5 mL h−1 in a 0.5 or 1 L reactor and <10 mL h−1 in a 2-L reactor. Mitigating the effects of atmospheric pressure variations on biodegradation test includes lowering the reactor volume, increasing the test material amount and recording atmospheric pressure for further modification.
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| 5. |
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| 6. |
- Mieliauskiene, R, et al.
(författare)
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Amperometric determination of acetate with a tri-enzyme based sensor
- 2006
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Ingår i: Sensors and Actuators B: Chemical. - : Elsevier BV. - 0925-4005. ; 113:2, s. 671-676
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Tidskriftsartikel (refereegranskat)abstract
- The present work describes a flow injection analysis system incorporating amperometric biosensors for acetate monitoring. Tri-enzyme-modified electrodes were fabricated by immobilizing acetate kinase (AK), pyruvate kinase (PK) and lactate dehydrogenase (LDH) into a poly(ethyleneglycole) diglycidyl ether (PEGDGE) film also containing Brilliant Cresyl Blue (BCB) as an electrochemical mediator. The concentration of acetate could be determined from the decrease in the amperometric current at +50 mV versus Ag/AgCl. Parameters, such as composition of the biosensing film, operational conditions (e.g., applied potential, flow rate) were optimized. The optimized biosensor showed a linear response to acetate in the range of 0.2-8 mM with a detection limit of 0.13 mM (calculated as 3 SIN). The acetate content of different samples (wine and vinegar) could be reliably quantified with the described biosensor.
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| 7. |
- Muresan, Laura, et al.
(författare)
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Amine oxidase amperometric biosensor coupled to liquid chromatography for biogenic amines determination
- 2008
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Ingår i: MICROCHIMICA ACTA. - : Springer Science and Business Media LLC. - 0026-3672 .- 1436-5073. ; 163:3-4, s. 219-225
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Konferensbidrag (refereegranskat)abstract
- A selective and sensitive method is presented for biogenic amines (BA) determination. The novelty consists in coupling a highly selective electrochemical biosensor to a weak acid cation-exchange column for online detection of amines. A bienzyme design, based on a recently isolated amine oxidase from grass pea and commercial horseradish peroxidase, was used for the biosensor construction. The enzymes were co-immobilized on the surface of a graphite electrode together with the electrochemical mediator (Os-redox polymer). The electrochemical detection was performed at a low applied potential (-50 mV vs. Ag/AgCl, KCl0.1 M), where biases from interferences are minimal. The separation and determination of six BA, with relevance in food analysis (tyramine, putrescine, cadaverine, histamine, agmatine and spermidine), were investigated. Irrespective of the BA nature, the amine oxidase-based biosensor showed a linear response up to 5 mM, and its sensitivity decreases in the following order: cadaverine, putrescine, spermidine, agmatine, histamine and tyramine. The approach was used to estimate the BA content in fish samples, after their extraction with methanesulfonic acid.
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| 8. |
- Muresan, Laura, et al.
(författare)
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AMPEROMETRIC BIOSENSORS FOR GLUCOSE AND ETHANOL DETERMINATION IN WINE USING FLOW INJECTION ANALYSIS
- 2008
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Ingår i: Studia Universitatis Babes-Bolyai, Chemia. - 2065-9520. ; 53:1, s. 71-79
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Tidskriftsartikel (refereegranskat)abstract
- Reagentless amperometric biosensors for glucose and ethanol were developed and successfully applied for monitoring glucose and ethanol concentrations in wine during the fermentation process. The glucose biosensor was based on commercially available glucose oxidase and horseradish peroxidase co-immobilized on solid graphite using Os(II)-redox hydrogel (RH) [1]. In the case of ethanol biosensor, the quinohemoprotein dependent alcohol dehydrogenase was immobilized on the graphite electrode surface using the same RH [2]. Both biosensors were operated at low applied potentials (-50 mV vs. Ag/AgCl, KCl0.1M for glucose biosensor, and +250 mV vs. Ag/AgCl, KCl0.1M for ethanol biosensor), where biases from interferences are minimal. The bioelectroanalytical parameters, estimated from flow injection analysis measurements, were found as follows: sensitivity, 0.73 +/- 0.01 mu A mM(-1) for glucose and 0.45 +/- 0.01 mu A mM(-1) for ethanol; linear range up to 1 mM in both cases; detection limit, 7.0 mu M for glucose and 8.9 mu M for ethanol. The results for real samples were found in good agreement with those reported by Barsan et al. [3].
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| 9. |
- Muresan, Laura, et al.
(författare)
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Monitoring of glucose and glutamate using enzyme microstructures and scanning electrochemical microscopy.
- 2009
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Ingår i: Bioelectrochemistry. - : Elsevier BV. - 1878-562X .- 1567-5394. ; 76, s. 81-86
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Tidskriftsartikel (refereegranskat)abstract
- Glucose oxidase and glutamate oxidase lines, with typical width of 100 microm, were patterned on gold surfaces using a micro-dispensing system, by shooting 100 pl droplets of the corresponding enzyme solutions. The probe of a scanning electrochemical microscope (SECM) was then carefully positioned in the close proximity of the enzyme microstructure and poised to +600 mV vs. Ag/AgCl, KCl 0.1 M. The H(2)O(2), generated by the enzyme lines at different concentrations of glucose and glutamate in the surrounding solution, was sequentially monitored. Reproducible calibration curves for glucose and glutamate were obtained in one single experiment, proving that the combination of enzyme microstructures with SECM can provide a new way of achieving multianalyte detection.
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| 10. |
- Muresan, Laura, et al.
(författare)
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Reagentless Amperometric Biosensor For Nadh Detection
- 2009
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Ingår i: Revue Roumaine de Chimie. - 0035-3930. ; 54:9, s. 755-760
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Tidskriftsartikel (refereegranskat)abstract
- A sensitive and selective amperometric biosensor, based on NADH-oxidase (NADOx) working in tandem with horseradish peroxidase (HRP), which is electrically connected to graphite electrode via Os-redox polymer (RP), was developed. Two designs were considered for the biosensor optimization: (i) the first one, [G/HRP-NADOx], exploited the direct electron transfer between HRP and the graphite electrode (G); (ii) the second one, [G/RP-HR-P-NADOx], used R-P as mediator. In both cases the enzyme matrix was cross-linked using poly(ethylenglycol) diglycidyl ether. The biosensors sensitivities, estimated as the slopes of linear ranges from the calibration curves, recorded in a single line flow injection setup, showed that G/RP-HRP-NADOx electrode (1.62 +/- 0.05 mA M-1) presents a higher efficiency than G/HRP-NADOx electrode (0.30 +/- 0.03 mA M-1).
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