Electroimmobilization of nitrate reductase and nicotinamide adenine dinucleotide into polypyrrole films for potentiometric detection of nitrate

Sohail, Manzar; Adeloju, Samuel B O

doi:10.1016/j.snb.2008.02.032

Cited by 36 publications

(32 citation statements)

References 43 publications

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“…A particular focus is to develop a readily employed strategy for co-entrapment of NaR and the mediator into PPy films. As demonstrated in our previous study [17], this can best be achieved by galvanostatic polymerization of pyrrole. This will require consideration of factors such as pyrrole, NaR, mediator and electrolyte concentrations, as well as the influence of applied current density and polymerization time.…”

Section: Introductionmentioning

confidence: 67%

“…Further increase in AzA concentration resulted in a slight reduction of the nitrate potentiometric response due to the saturation of the film or increased film thickness [24]. When compared to b-NADH [17], very low concentration of AzA was required for the adequate performance of the potentiometric biosensor. Thus, only 50 mM of AzA (compared to 0.3 mM NADH [13]) was used for all further investigations.…”

Section: Choice Of Enzyme and Azure-a Concentrationsmentioning

confidence: 99%

“…Also the linear concentration ranges achieved with PPy-NaR-AzA, PPy-NaR-MV and PPy-NaR-ThAc biosensors were better than that of PPy-NaR-NADH biosensor. Even the incorporation of BrB and BrR with NaR permit the achievement of similar sensitivity to that of PPy-NaR-NADH biosensor [17]. Thus, the combination of suitable redox mediator with NaR offers better and much cheaper alternatives to the use of NADH or NAD(P)H for the fabrication of more sensitive and reliable potentiometric nitrate biosensor.…”

Section: Analytical Utilizationmentioning

confidence: 99%

“…In a recent study, we reported on the development of a sensitive nitrate potentiometric biosensor by immobilization of NaR and b-NADH into a polypyrrole film [17]. b-NADH is not only regarded as a cofactor and prosthetic group, but it is also sometimes referred to as a low molecular weight redox mediator or electron carrier [8].…”

Section: Introductionmentioning

confidence: 99%

“…b-NADH is not only regarded as a cofactor and prosthetic group, but it is also sometimes referred to as a low molecular weight redox mediator or electron carrier [8]. The presence of b-NADH in the polypyrrole film resulted in a considerable increase in the nitrate potentiometric response [17]. Evidently, the co-entrapment of NADH in the polymer film is essential for achieving improved sensitivity of the nitrate biosensor.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Fabrication of Redox‐Mediator Supported Potentiometric Nitrate Biosensor with Nitrate Reductase

Sohail

Adeloju

2009

Electroanalysis

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Fabrication of a more superior nitrate potentiometric biosensor than previously achieved with NaR and NADH has been accomplished by co-entrapment of redox mediators and NaR into polypyrrole (PPy) film during galvanostatic polymerization of pyrrole. The replacement of NADH with redox mediators such as thionin acetate (ThAc), safranin (Saf), and azure A (AzA) gave more sensitive potentiometric responses, better minimum detectable concentration, linear concentration range and response time for nitrate than possible with NADH. The co-entrapment of ThAc, Saf, AzA and methyl viologen (MV) with NaR into PPy films also improved the Nernstian behavior of the electrode process beyond the capability of the PPy-NaR-NADH biosensor. Substantial reduction in volume and quantity of cofactor/mediator and, hence cost, was achieved by the replacement of NADH with a redox mediator. Only 50 mM of AzA was required to form a PPy-NaR-AzA biosensor which gave the most sensitive potentiometric response for nitrate, achieving a minimum detectable concentration of 10 mM, a linear concentration range of 50 -5000 mM and a response time of 2 -4 s.

show abstract

Section: Introductionmentioning

confidence: 67%

Section: Choice Of Enzyme and Azure-a Concentrationsmentioning

confidence: 99%

Section: Analytical Utilizationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Fabrication of Redox‐Mediator Supported Potentiometric Nitrate Biosensor with Nitrate Reductase

Sohail

Adeloju

2009

Electroanalysis

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Disposable potentiometric citrate sensor based on polypyrrole‐doped films for indirect determination of sildenafil in pharmaceuticals formulations

Ochiai

Bindewald

Mengarda

et al. 2016

J of Applied Polymer Sci

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A new sensitive and selective disposable potentiometric sensor based on polypyrrole (PPy) films for determination of sildenafil citrate (SC) was proposed. The pyrrole polymerization was performed in presence of citrate ions under galvanostatic conditions which resulted in a membrane of PPy doped with citrate anion at graphite pencil electrode surface. Experimental conditions (e.g., pH and conditioning time) and instrumental parameters (e.g., current density and electrical charge) were evaluated in order to reach the best potentiometric response for the proposed sensor. Under optimized conditions, the device presented a linear dynamic range (LDR) for citrate ions concentrations varying from 0.034 to 1.7 mmol L 21 with a Nernstian slope of 57.2 mV dec 21 and a limit of detection (LOD) of 30 mmol L 21 . The developed potentiometric sensor was applied for sildenafil citrate (SC) determination (pharmaceutical formulations) and results compared with an official spectrophotometric method indicating a good agreement for a confidence level of 95%. Effect of concomitants species on the potentiometric response of the proposed device and morphologic characterization using microscopy of atomic force (AFM) were realized. The surface roughness of PPy films (synthesized in citrate solution and chloride) showed poorly affected by changing the doping anion, probably because the polypyrrole nodules grow three-dimensionally simultaneously. V C 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43762.

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Azure A Mediated Polypyrrole‐Based Amperometric Nitrate Biosensor

Adeloju

Sohail

2011

Electroanalysis

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The co-entrapment of Aspergillus niger-nitrate reductase (NaR) and azure A (AzA), as a redox mediator has been investigated for fabrication of a polypyrrole (PPy)-based electron mediated amperometric nitrate biosensor. Optimum formation of PPy-NaR-AzA film was achieved in a monomer solution which contained 0.3 M Py, 0.1 M KCl, 1U/mL NaR, 50 mM AzA with an applied current density of 0.5 mA/cm 2 for 240 s. The optimum applied potential of À0.25 V for amperometric detection of nitrate with PPy-NaR-AzA biosensor was 50, 100 and 150 mV more positive than those achieved with the use of safranin O (Saf), methyl viologen (MV) and bromophenol blue (BrB) or red (BrR), respectively, as mediators. Similar optimum applied of À0.25 V was achieved with thionin acetate (ThAc) which was in the same phenothiazine group of mediators as AzA. The electron mediated amperometric detection of nitrate with the PPy-NaR-AzA biosensor also gave the best performance with a sensitivity of 40.8 nA mM À1 cm À2 , detection limit of 0.5 mM, a response time of 18-20 s and a linear concentration range of 20-500 mM.

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Electroimmobilization of nitrate reductase and nicotinamide adenine dinucleotide into polypyrrole films for potentiometric detection of nitrate

Cited by 36 publications

References 43 publications

Fabrication of Redox‐Mediator Supported Potentiometric Nitrate Biosensor with Nitrate Reductase

Fabrication of Redox‐Mediator Supported Potentiometric Nitrate Biosensor with Nitrate Reductase

Disposable potentiometric citrate sensor based on polypyrrole‐doped films for indirect determination of sildenafil in pharmaceuticals formulations

Azure A Mediated Polypyrrole‐Based Amperometric Nitrate Biosensor

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