scholarly journals An Amperometric Biosensor Based on Alanine Dehydrogenase for the Determination of Low Level of Ammonium Ion in Water

2011 ◽  
Vol 2011 ◽  
pp. 1-10 ◽  
Author(s):  
Tan Ling Ling ◽  
Musa Ahmad ◽  
Lee Yook Heng
Keyword(s):  
Linear Response ◽  
Limit Of Detection ◽  
Colorimetric Method ◽  
Ion Concentration ◽  
Ammonium Ion ◽  
Carbon Paste ◽  
Alanine Dehydrogenase ◽  
Response Range ◽  
Paste Electrode

An amperometric electrochemical biosensor has been developed for ammonium (NH4+) ion detection by immobilising alanine dehydrogenase (AlaDH) enzyme in a photocurable methacrylic membrane made up of poly(2-hydroxyethyl methacrylate) (pHEMA) on a screen-printed carbon paste electrode (SPE). The current detected was based on the electrocatalytic oxidation of nicotinamide adenine dinucleotide reduced (NADH) that is proportional to the consumption ofNH4+ion whilst enzymatic amination of AlaDH and pyruvate is taking place. The biosensor was operated amperometrically at a potential of +0.6 V and optimum pH 7. TheNH4+biosensor demonstrated linear response toNH4+ion concentration in the range of 0.03–1.02 mg/L with a limit of detection (LOD) of 8.52 μg/L. The proposed method has been successfully applied to the determination ofNH4+ion in river water samples without any pretreatment. The levels of possible interferents in the waters were negligible to cause any interference on the proposed method. The analytical performance of the biosensor was comparable to the colorimetric method using Nesslerisation but with much lower detection limit and linear response range at ppb level.

scholarly journals The Effect of Multilayer Gold Nanoparticles on the Electrochemical Response of Ammonium Ion Biosensor Based on Alanine Dehydrogenase Enzyme

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Tan Ling Ling ◽  
Musa Ahmad ◽  
Lee Yook Heng ◽  
Toh Chee Seng
Keyword(s):  
Gold Nanoparticles ◽  
Electrode Surface ◽  
Linear Response ◽  
Gold Electrode ◽  
Thiol Group ◽  
Ion Concentration ◽  
Ammonium Ion ◽  
Current Response ◽  
Alanine Dehydrogenase ◽  
Response Range

The use of multilayer of gold nanoparticles (AuNPs) attached on gold electrode surface via thiol chemistry to fabricate an ammonium (NH4+) ion biosensor based on alanine dehydrogenase (AlaDH) was investigated. The approach of the study was based on construction of biosensor by direct deposition of AuNPs and 1,8-octanedithiol (C8-DT) onto the gold electrode surface. For the immobilisation of enzyme, 2-mercaptoethanol (2BME) was first covalently attached to AlaDH via esther bonding and then followed by chemically attached the 2BME-modified AlaDH (2BME-AlaDH) moiety onto the AuNPs electrode via the exposed thiol group of 2BME. The resulting biosensor response was examined by means of amperometry for the quantification ofNH4+ion. In the absence of enzyme attachment, the use of three layers of AuNPs was found to improve the electrochemistry of the gold electrode when compared with no AuNPs was coated. However, when more than three layers of AuNPs were coated, the electrode response deteriorated due to excessive deposition of C8-DT. When AlaDH was incoporated into the AuNPs modified electrode, a linear response toNH4+ion over the concentration range of 0.1–0.5 mM with a detection limit of 0.01 mM was obtained. In the absence of AuNPs, theNH4+ion biosensor did not exhibit any good linear response range although the current response was observed to be higher. This work demonstrated that the incorporation of AuNPs could lead to the detection of higherNH4+ion concentration without the need of dilution for highNH4+ion concentration samples with a rapid response time of <1 min.

A Facile In-Situ Development of L-Valine Film onto the Surface of Carbon Paste Electrode Towards the Detection of Environmentally Hazardous 4-Amino Phenol

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
T. Venu Gopal ◽  
Tukiakula Madhusudana Reddy ◽  
P. Shaikshavali ◽  
G. Venkataprasad ◽  
P. Gopal
Keyword(s):  
Cyclic Voltammetry ◽  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Small Scale ◽  
Carbon Paste ◽  
Relative Standard ◽  
Paste Electrode

Abstract A small scale of environmentally hazardous 4-aminophenol can show significant impact on human health. Hence, in the present work, we have designed L-Valine film (Vf) modified carbon paste electrode (Vf/CPE) for the determination of 4-aminophenol. Herein, a facile in-situ L-Valine film was developed by electrochemical polymerization method onto the surface of bare carbon paste electrode (BCPE) with the help of cyclic voltammetry (CV) technique. A two-folds of electrochemical peak current enhancement was achieved at Vf/CPE in comparison with BCPE towards the determination of 4-aminophenol in optimum pH 7.0 of phosphate buffer solution (PBS). This was achieved due to the large surface area and conductive nature of Vf/CPE, which was concluded through the techniques of cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The effect of pH of buffer and scan rate studies were successfully studied. Morphological changes of BCPE and Vf/CPE was studied with the help of scanning electron microscopy (SEM). The formation of Vf on CPE was also analyzed by Fourier transform infrared (FTIR) spectra. Under the optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) values of 4-aminophenol were estimated with the aid of chronoamperometry (CA) technique and was found to be 9.8 μM and 32 μM, respectively. Finally the proposed method was found to have satisfactory repeatability, reproducibility and stability results with low relative standard deviation (RSD) values.

scholarly journals Electrocatalytic determination of levodopa in presence of cabergoline using carbon paste electrode modified with graphene quantum dots/2-chlorobenzoyl ferrocene/ionic liquid

2021 ◽  
Author(s):  
Peyman Mohammadzadeh Jahani
Keyword(s):  
Quantum Dots ◽  
Ionic Liquid ◽  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Graphene Quantum Dots ◽  
Simultaneous Detection ◽  
Phosphate Buffer Solution ◽  
Carbon Paste ◽  
Paste Electrode

The electrochemical sensor was fabricated for the simultaneous determination of levodopa and cabergoline using carbon paste electrode (CPE) modified with graphene quantum dots (GQD), 2-chlorobenzoyl ferrocene (2CBF) and ionic liquid (IL). Then, the electrochemical behavior of levodopa alone and simultaneously with cabergoline at the surface of GQDs/2CBF/IL/CPE was investigated in phosphate buffer solution (PBS). Under optimal PBS, pH=7 condition, oxidation peak current has been found proportional to levodopa concentration in the range between 0.07 μM and 500.0 μM, with the limit of detection (LOD) of 0.02 μM (S/N=3). Outputs showed that at GQDs/2CBF/IL/CPE surface, the levodopa and cabergoline oxidation peaks are separated by the potential difference of 200 mV. In addition, it was found that this modified electrode possesses acceptable sensitivity, selectivity, stability and repeatability. All these properties were sufficient to allow simultaneous detection of levodopa and cabergoline in real samples at the surface of GQDs/2CBF/IL/CPE. This was supported by the successful application of this electro­chemical sensor electrode for the determination of levodopa and cabergoline in urine, serum, and cabergoline tablets.

scholarly journals Preparation and Charactreization Selective Electrode for Determination of CopperIon(II)

2016 ◽  
Vol 5 (4) ◽  
pp. 237
Author(s):  
Salwa Fares Rassi
Keyword(s):  
Carbon Paste Electrode ◽  
Linear Response ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
Selective Electrode ◽  
Chemically Modified ◽  
Diphenyl Carbazide ◽  
Nernstian Slope ◽  
Paste Electrode

<span>Achemically modified carbon paste electrode with diphenyl carbazide the potentiometric determination of Cu(II) is demonstrated. The electrode exhibits linear response to Cu(II) over a wide concentration range (9.2×10−7-5.0×10−1) with Nernstian slope of 30±0.15 mV per decade. It has a response time of about 40 s and can be used for a period of two months with good reproducibility. The detection limit of this electrode was 7.0×10−7 M. The proposed electrode shows a very good selectivity for Cu(II) over a wide variety of metal ions. This chemically modified carbon paste electrode was successfully used for the determination of Cu(II) in various water samples solution and pharmaceutical formulation</span>

Voltammetric study of secnidazole and its determination in pharmaceutical tablet using 1, 4-benzoquinone modified carbon paste electrode

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Modified Carbon Paste Electrode ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Limit Of Quantification ◽  
Pharmaceutical Tablet ◽  
Relative Standard ◽  
Paste Electrode

In this study voltammetric behaviour of secnidazole (SCZ) at 1, 4-Benzoquinone Modified Carbon Paste Electrode (1,4-BQMCPE) was investigated in Britton Robinson buffer solution using cyclic voltammetric technique. A well-defined cathodic peak was observed for the SCZ in the entire pH range. The current increases steadily with scan rate and the results indicated that the process is irreversible reduction and adsorption controlled. The number of electrons transferred and different kinetic parameters like transfer coefficient and rate constant were calculated by using cyclic voltammetry technique. Differential pulse voltammetric method has been used for the determination of SCZ content in pharmaceutical tablet. This method enabled to determine SCZ in the concentration range 1.0 × 10-8 to 4.0 × 10-4 M. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 2.13 × 10-9 and 2.85 × 10-9 respectively. The method was applied to determine the content of SCZ in different sample solutions of SCZ tablet with excellent recovery and relative standard deviation results (99.892±1.53 respectively) for spiked standard SCZ in tablet sample solutions. The selectivity of the method for SCZ was further studied in the presence of selected potential interferents such as fluconazole, azithromycin etc and confirmed the potential applicability of the developed method for the determination of SCZ in real pharmaceutical tablets.

Indirect Differential Pulse Voltammetric Determination of Fluoride Ions at Carbon Paste Electrode Modified with Porous and Electroactive Fe3+/Fe2+ Based-Metal Organic Frameworks Type MIL-101(Fe)

2021 ◽  
Author(s):  
Ashraf Mahmoud ◽  
Mater Mahnashi ◽  
Samer Abu-Alrub ◽  
Saad Kahatani ◽  
Mohamed El-Wekil
Keyword(s):  
Carbon Paste Electrode ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Metal Organic Frameworks ◽  
Differential Pulse ◽  
Carbon Paste ◽  
X Ray ◽  
Metal Organic ◽  
Paste Electrode

Abstract An innovative and reliable electrochemical sensor was proposed for simple, sensitive and selective determination of F- ions. The sensor is based on the fabrication of porous and electroactive Fe-based metal organic frameworks [MIL-101(Fe)]. It was blended with graphite powder and liquid paraffin oil to from carbon paste electrode (CPE). The MIL-101(Fe)@CPE was characterized using different techniques such as scanning electron microscope, powder X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, energy dispersive X-ray, cyclic voltammetry, electrochemical impedance spectroscopy, differential pulse voltammetry. The MIL-101(Fe)@CPE exhibited two redox peaks (anodic and cathodic) corresponding to Fe3+ and Fe2+, respectively. The determination of F- ions based on the formation of a stable fluoroferric complex with Fe3+/ Fe2+, decreasing the currents of redox species. It was found that the anodic peak current (Ipa) is linearly proportional to the concentration of F- in the range of 0.67-130 µM with a limit of detection (S/N=3) of 0.201 µM. The electrode exhibited good selectivity towards F- detection with no significant interferences from common anions. The as-fabricated sensor was applied for the determination of F- in environmental water samples with recoveries % and RSDs % in the range of 98.1-102.4 % and 2.4-3.7 %, respectively.

scholarly journals Detection of dopamine by a minimized electrochemical sensor using a graphene oxide molecularly imprinted polymer modified micropipette tip shaped graphite electrode

2021 ◽  
pp. 174751982198995
Author(s):  
Yi Wang ◽  
Jianshe Tang ◽  
Li Xiang
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Sensor ◽  
Molecularly Imprinted Polymer ◽  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Carbon Paste ◽  
Imprinted Polymer ◽  
Molecularly Imprinted ◽  
Paste Electrode

A simple and efficient electrochemical sensor based on a homemade reshaped micropipette tip carbon paste electrode is reported. Molecularly imprinted polymer membranes of graphene oxide and polypyrrole are synthesized and modified on the surface of micropipette tip carbon paste electrode. The merit of the method is evaluated under optimized conditions via differential pulse voltammetrics. The prepared sensor exhibits remarkable sensitivity toward dopamine with a linear range of 6.4 × 10−8–2 × 10−4 M, with a limit of detection as low as 1 × 10−8 M. The proposed method is applied for the determination of dopamine in urine samples by the standard addition route. A range of 1 × 10−7–1 × 10−4 M is obtained from these samples. The relative recoveries are in the range of 95.2%–104%. The proposed method has acceptable performance for the determination of dopamine in real samples with excellent sensitivity and selectivity.

scholarly journals Electrochemical Investigation of Catechol at Poly(niacinamide) Modified Carbon Paste Electrode: A Voltammetric Study

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
A. B. Teradale ◽  
S. D. Lamani ◽  
B. E. Kumara Swamy ◽  
P. S. Ganesh ◽  
S. N. Das
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Modified Carbon Paste Electrode ◽  
Rate Variation ◽  
Carbon Paste ◽  
Buffer Solution ◽  
Limit Of Quantification ◽  
Paste Electrode

A polymeric thin film modified electrode, that is, poly(niacinamide) modified carbon paste electrode (MCPE), was developed for the electrochemical determination of catechol (CC) by using cyclic voltammetric technique. Compared to bare carbon paste electrode (BCPE), the poly(niacinamide) MCPE shows good electrocatalytic activity towards the oxidation of catechol in phosphate buffer solution (PBS) of physiological pH 7.4. All experimental parameters were optimized. Poly(niacinamide) modified carbon paste electrode gave a linear response between concentration of CC and its anodic peak current in the range within 20.6–229.0 μM. The limit of detection (3S/M) and limit of quantification (10S/M) were 1.497 μM and 4.99 μM, respectively. From the study of scan rate variation, the electrode process was found to be adsorption-controlled. The involvement of protons and electrons in the oxidation of CC was found to be equal. The probable electropolymerisation mechanism of niacinamide was proposed. Finally, this method can be used in development of a sensor for sensitive determination of CC.

scholarly journals MODIFICATION OF CARBON PASTE ELECTRODE WITH CROWN ETHER (DIBENZO-18-CROWN-6) FOR ASCORBIC ACID ANALYSIS USING DIFFERENTIAL PULSE VOLTAMMETRY METHOD

2016 ◽  
Vol 11 (2) ◽  
pp. 175
Author(s):  
Irdhawati Irdhawati ◽  
Manuntun Manurung ◽  
Anisha Maulinasari
Keyword(s):  
Ascorbic Acid ◽  
Crown Ether ◽  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Differential Pulse ◽  
Modified Carbon Paste Electrode ◽  
Range Limit ◽  
Carbon Paste ◽  
Paste Electrode

In this research, the modified carbon paste electrode with crown ether (dibenzo-18-crown-6) has been prepared, for determination of ascorbic acid. Some of parameters observed were optimization of crown ether composition in carbon paste, pH of solution, linear concentration range, limit of detection, reproducibility, and recovery. The optimum performance of the prepared electrode was applied for determination of commercialsampleswhich contain of ascorbic acid. The result of this research showsthat the optimum composition of crown ether in carbon paste is 0.6 % at pH 4. Linear range of concentration obtained is from 2 - 200 μM. The detection limit and percentage of recovery are 1.243 μM and 101.31 %, respectively. The modified electrode has HorRat value less than 2, it indicates a good reproducibility. Analysis of 4 commercial samples which contain of ascorbic acid were in agreement with the content listed in the label with the suitability of 94 - 100 %.

scholarly journals Electrochemical Analysis of Fenuron Herbicide by a Carbon Paste Electrode Modified by a Functionalized NiAl-layered Double Hydroxide

2021 ◽  
Author(s):  
TCHEUMI Herve Leclerc ◽  
KAMENI WENDJI Aude Peggy ◽  
TONLE KENFACK Ignas ◽  
NGAMENI Emmanuel
Keyword(s):  
Composite Material ◽  
Layered Double Hydroxide ◽  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Detection Methods ◽  
Carbon Paste ◽  
Linear Calibration ◽  
Double Hydroxide ◽  
Paste Electrode

Abstract Environmental pollution by usage of pesticides as fenuron increases health risk, due to carcinogenic and teratogenic properties of these compounds. There are needs to develop a rapid and cheaper detection methods for quantification of fenuron. In this work, an inorganic-organic composite material was obtained by intercalation of sodium dioctylsulfosuccinate (DSS) within the interlayer space of a Nickel-Aluminum Layered Double Hydroxide (NiAl-LDH). The structure of the pristine LDH and the intercalated-LDH was confirmed using Fourier transform infrared spectroscopy, X-ray diffraction and thermal analysis. The modified LDH was used to elaborate an amperometric sensor for fenuron herbicide by differential pulse voltammetry (DPV) via a carbon paste electrode (CPE). The electrochemical procedure for fenuron analysis was based on the immersion of the working electrode in the electrolytic solution containing appropriate amount of herbicide, followed by voltammetry detection without any preconcentration step. The peak current obtained on the CPE modified by the organo-LDH was 2-fold higher in comparison with the pristine LDH/CPE. The observed increase in the signal of fenuron was attributed to the high organophilic character of this composite material induced by the modification using DSS. The effects of some experimental parameters (pH of medium and percentage of the modifier in the paste) on the stripping response were investigated in order to optimize the sensitivity of the organo-LDH modified electrode. Linear calibration curves were obtained in the fenuron concentration ranging from 0.5 to 1 μmol.L -1 and 1 to 5 μmol.L -1 . The limit of detection (LOD) calculated on the basis of a signal-to-noice ratio of 3 was 1.8×10 -9 mol.L -1 (low concentration range) and the limit of quantification (LOQ) was 6×10 -9 mol.L -1 . The interference effect of various inorganic ions likely to influence the stripping determination of the fenuron was also examined, and the applicability of the method was verified by the determination of fenuron in a river sample collected down-town Yaoundé.

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