Electrochemical Behavior Of Folic Acid Research Articles

PtNPs-GNPs-MWCNTs-β-CD nanocomposite modified glassy carbon electrode for sensitive electrochemical detection of folic acid.

A novel electrochemical sensor, platinum nanoparticles/graphene nanoplatelets/multi-walled carbon nanotubes/β-cyclodextrin composite (PtNPs-GNPs-MWCNTs-β-CD) modified carbon glass electrode (GCE), was fabricated and used for the sensitive detection of folic acid (FA). The PtNPs-GNPs-MWCNTs-β-CD nanocomposite was easily prepared with an ultrasound-assisted assembly method, and it was characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrochemical behavior of FA at PtNPs-GNPs-MWCNTs-β-CD/GCE was investigated in detail. Some key experimental parameters such as pH, amount of PtNPs-GNPs-MWCNTs-β-CD composite, and scan rate were optimized. A good linear relationship (R2 = 0.9942) between peak current of cyclic voltammetry (CV) and FA concentration in the range 0.02-0.50mmolL-1 was observed at PtNPs-GNPs-MWCNTs-β-CD/GCE. The detection limit was 0.48μmolL-1 (signal-to-noise ratio = 3). A recovery of 97.55-102.96% was obtained for the determination of FA in FA pills (containing 0.4mg FA per pill) at PtNPs-GNPs-MWCNTs-β-CD/GCE, indicating that the modified electrode possessed relatively high sensitivity and stability for the determination of FA in real samples.

Free‐standing and Flexible MoS2/rGO Paper Electrode for Amperometric Detection of Folic Acid

AbstractThe development of flexible electrodes is of considerable current interest because of the increasing demand for modern electronics, portable medical products, and compact devices. We report a new type of flexible electrochemical sensor fabricated by integrating graphene and MoS2 nanosheets. A highly flexible and free‐standing conductive MoS2 nanosheets/reduced graphene oxide (MoS2/rGO) paper was prepared by a two‐step process: vacuum filtration and chemical reduction treatment. The MoS2/graphene oxide (MoS2/GO) paper obtained by a simple filtration method was transformed into MoS2/rGO paper after a chemical reduction process. The obtained MoS2/rGO paper was characterized by scanning electron microscopy, X‐ray diffraction spectroscopy, X‐ray photoelectron spectroscopy, Raman spectroscopy, electrochemical impedance spectroscopy. The electrochemical behavior of folic acid (FA) on MoS2/rGO paper electrode was investigated by cyclic voltammetry and amperometry. Electrochemical experiments indicated that flexible MoS2/rGO composite paper electrode exhibited excellent electrocatalytic activity toward the FA, which can be attributed to excellent electrical conductivity and high specific surface area of the MoS2/rGO paper. The resulting biosensor showed highly sensitive amperometric response to FA with a wide linear range.

Sensitive Electrochemical Determination of Folic Acid Using ex–situ Prepared Bismuth Film Electrodes

The electrochemical behavior of folic acid (FA), at the electrochemically prepared ex situ bismuth film (BiF) on glassy carbon electrode, clearly indicates electrocatalytic nature of the prepared film toward FA reduction (at –0.55 V). Scanning electron microscopy is used for morphological characterization of the prepared BiF. Accordingly, we establishing an electrochemical procedure based on square wave cathodic stripping voltammetry, preceded by accumulation of FA on the BiF electrode (BiFE). This analytical method is optimized and its analytical performance is presented. This electrode displays a two linear response range: 0.1 to 1.0 μmol L–1 and 1.0 – 10.0 μmol L–1 with sensitivity of 20.10 μA μmol–1 L and 2.28 μA μmol–1 L, respectively. Developed method was validated in compliance with spectrophotometric method. Excellent recovery and standard deviation obtained with BiFE revealed great analytical potential of the proposed method which was applied for the determination of FA in pharmaceuticals formulation.

Adsorption effect of a cationic surfactant at carbon paste electrode as a sensitive sensor for study and detection of folic acid

The present study is the first report on the effect of cetyltrimethylammonium bromide (CTAB) on the electrochemical behavior of folic acid (FA) at the surface of carbon paste electrode (CPE) in real samples. The studies were performed by cyclic voltammetry (CV), chronocoulometry and differential pulse voltammetry (DPV). CTAB, with a hydrophobic C–H chain, could absorb at the CPE surface by hydrophobic interaction and then changed the electrode/solution interface, and eventually affects the electrochemical response of FA, confirming from the remarkable oxidation peak current enhancement. For investigation of the electrode properties, CV technique was used at the various scan rates. Electrochemical parameters including diffusion coefficient (D), electron transfer coefficient (α) and ionic exchanging current density (jo) were determined for the FA at the surface of the electrode. Under optimized conditions, the proposed method showed acceptable analytical performances for FA in terms of linearity (over the concentration range from 0.01 to 1.5 and 1.5 to 10.0μM), detection limit (2.89nM), repeatability (1.37%) and stability (13% reduction in peak current after 60days). After studying on the effect of probable interferences it was found that the method was free of the interferences. Finally, the proposed method was successfully applied for the determination of FA in real samples.

Simple and Rapid Quantification of Folic Acid in Pharmaceutical Tablets using a Cathodically Pretreated Highly Boron-doped Polycrystalline Diamond Electrode

ABSTRACTA simple, rapid, and sensitive electroanalytical method for the direct quantification of folic acid was developed using square-wave voltammetry with a cathodically pretreated highly boron-doped polycrystalline diamond electrode. The morphology and structure of this electrode were investigated by scanning electron microscopy and Raman spectroscopy. The electrochemical behavior of folic acid was studied by cyclic voltammetry and an irreversible oxidation peak was observed at +0.78 volt vs. Ag/AgCl in Britton-Robinson buffer at pH 5. Using optimized square-wave voltammetric parameter values, the response of folic acid was linear from 0.1 to 167 micromolar with a limit of detection of 30 nanomolar with good repeatability. The influence of some interfering compounds was also evaluated. The method was successfully applied to the quantification of folic acid in pharmaceutical tablets. Considering the importance of the analyte upon human health, the boron-doped diamond electrode may be employed as an effective alternative electroanalytical approach.

Electrochemical Determination of Folic Acid at Sodium Alpha Olefin Sulphonate Modified Carbon Paste Electrode: A Voltammetric Study

Sodium alpha olefin sulphonate (SAOS) was used for the modification of carbon paste electrode (CPE) to determine the electrochemical behavior of folic acid (FA) in 0.2M phosphate buffer solution (PBS) at pH 7.4 with the scan rate of 50 mVs-1. The effects of scan rate, concentration and simultaneous determination of FA at modified carbon paste electrode (MCPE) were studied. The effect of interference of dopamine was carried out and real sample analysis of FA was studied at MCPE. From the scan rate and concentration shows that, the overall electrode process was found to be diffusion-controlled at SAOSMCPE and detection limit was found to be 28.8 μM. The modified electrode (SAOSMCPE) exhibits good electrocatalytic activity towards the determination of folic acid when compared to BCPE. The same method can also be applied for other drug analysis.

A novel phosphomolybdic acid–polypyrrole/graphene composite modified electrode for sensitive determination of folic acid

A novel phosphomolybdic acid–polypyrrole/graphene composite modified glassy carbon electrode has been fabricated for the sensitive determination of folic acid based on the inhibitory activity of folic acid towards the redox behavior of Keggin-type phosphomolybdic acid. The redox behavior of the modified glassy carbon electrode is investigated by cyclic voltammetry and the electrochemical behavior of folic acid is studied by differential pulse voltammetry. From this study, it is found that on the modified electrode the redox process of phosphomolybdic acid is surface-controlled, which can form a much stronger complex with folic acid than H+ in 0.01M H2SO4. The reduced peak current of phosphomolybdic acid has a good linear relationship with FA concentration in the range from 1.0×10−9 to 2.0×10−7M, and the detection limit of FA is calculated to be 3.3×10−11M.

ZnO nanoparticle-modified ionic liquid-carbon paste electrodefor voltammetric determination of folic acid in food and pharmaceutical samples

In this work, a ZnO/nanoparticles (NPs) modified carbon ionic liquid paste electrode (ZnO/NP/CILPE) was fabricated and used to investigate the electrochemical behavior of folic acid. ZnO/NP/CILPE was prepared by mixing hydrophilic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([C4mim]-[PF6])), ZnO/NPs, graphite powder, and liquid paraffin together. The fabricated ZnO/NP/CILPE showed great electrocatalytic ability to the oxidation of folic acid, and an irreversible oxidation peak appeared at 0.75 V (vs. Ag/AgCl) with improved peak current. Under the optimized conditions of pH 9.0, the plot of peak current vs. folic acid concentration consisted of two linear segments with slopes of 1.776and 0.033 μA/μM in the concentration ranges of 0.05–1.5 μM and 1.5–550.0 μM, respectively. The detection limit was 0.01 μM (3σ). The proposed sensor was successfully applied for the determination of folic acid in fortified food and pharmaceutical samples.

Electrochemical behavior of folic acid in neutral solution on the modified glassy carbon electrode: Platinum nanoparticles doped multi-walled carbon nanotubes with Nafion as adhesive

Platinum nanoparticles (PtNPs) were used in combination with multi-walled carbon nanotubes (MWCNTs) with Nafion as the adhesives for fabricating sensitivity-enhanced electrochemical folic acid (FA) sensor. The modifier, PtNPs doped MWCNTs (PtNPs/MWCNTs), was characterized by transmission electron microscopy (TEM) and electrochemical method, it also showed an excellent character for electrocatalytic oxidization of FA. In addition, the experimental parameters such as pH values, the concentration of PtNPs/MWCNTs and the scan rate were optimized. Due to the fine characteristics of PtNPs/MWCNTs, a good linear relationship between the anodic peak current and FA concentration in the range 2.0×10−7–1.0×10−4M was observed. The detection limit of 5.01×10−8M was achieved with the linear correlation coefficient R=0.9948. The relative standard derivation was 1.9% for 5×10−6M FA in 11 repeated determinations. This modified electrode showed excellent sensitivity and stability for the determination of FA.

Voltammetric Determination of Folic Acid with a Overoxidized Polypyrrole Film Modified Sol-Gel Carbon Ceramic Electrode

The electrochemical behavior of folic acid (FA)was studied at an overoxidized polypyrrole modified carbon ceramic electrode using cyclic voltammetry. The numerous factors affecting the oxidation peak currents of folic acid on the response of the electrode were optimized to maximize sensitivity. The modified electrode presented a linear response range for FA concentration from 7 to 55 µM, 0.1 to 25 µM, and from 0.49 to 7.8 µM with detection limits of 1.8 × 10−6, 3.1 × 10−8, and 2.7 × 10−7 for cyclic voltammetry, differential pulse voltammetry, and amperometric techniques, respectively. The results showed that the OPPy-modified electrode has very high catalytic ability for electrooxidation of FA. The modified electrode exhibited excellent sensitivity and stability. The application of the modified electrode was demonstrated for determination of folic acid in biological and other real samples.

Electrochemical behavior and analytical determination of folic acid on carbon nanotube modified electrode

The electrochemical behavior of folic acid (FA) was investigated on carbon nanotube modified electrode with cyclic voltammetry and square wave stripping voltammetry. The effect of pH and scan rate was discussed too. The results indicated that the reaction was controlled by diffusion and was a process with equal numbers of electrons and protons. The number of electrons, diffusion coefficient and other important parameters of FA on modified electrode were estimated. The standard curve was studied with square wave stripping voltammetry. A good linearity was observed in the correlation between the peak current of FA and its concentration in the range of 3.00 × 10−7 ∼ 8.00 × 10−5 M. The detection limit was 1.34 × 10−7 M, the content of FA in compound prescription liver piece was detected with this method in optimized conditions and its recovery rate is between 92.00 and 107.0%.

Electrochemical behavior of folic acid at calixarene based chemically modified electrodes and its determination by adsorptive stripping voltammetry

Voltammetric behavior of folic acid at plain carbon paste electrode and electrode modified with calixarenes has been studied. Two peaks for irreversible oxidation were observed. Out of the three calixarenes chosen for modification of the electrodes, p- tert-butyl-calix[6]arene modified electrode (CME-6) was found to have better sensitivity for folic acid. Chronocoulometric and differential pulse voltammetric studies reveal that folic acid can assemble at CME-6 to form a monolayer whose electron transfer rate is 0.00273 s −1 with 2-electron/2-proton transfer for the peak at +0.71 V against SCE. An adsorption equilibrium constant of 5 × 10 3 l/mol for maximum surface coverage of 2.89 × 10 −10 mol/cm 2 was obtained. The current is found to be rectilinear with concentration by differential pulse voltammetry. However, linearity in the lower range of concentration 8.79 × 10 −12 M to 1.93 × 10 −9 M with correlation coefficient of 0.9920 was achieved by adsorptive stripping voltammetry. The limit of detection obtained was found to be 1.24 × 10 −12 M. This method was used for the determination of folic acid in a variety of samples, viz. serum, asparagus, spinach, oranges and multivitamin preparations.

Voltammetric behavior study of folic acid at phosphomolybdic-polypyrrole film modified electrode

The electrochemical behavior of folic acid at the Keggin-type phosphomolybdate (PMo 12) doped polypyrrole (PPy) film modified glassy carbon electrode (PMo 12-PPy/GCE) was studied. PMo 12 doped PPy modified electrodes were achieved during the electrochemical preparation of the polymer films in aqueous solution. The redox behavior of the modified electrode was described by cyclic voltammetry. The electrochemical behavior of folic acid at PMo 12-PPy/GCE was studied by 0.5 order differential voltammetry. Numerous factors affecting the reduction peak currents of folic acid at PMo 12-PPy/GCE were optimized to maximize the sensitivity. The results showed that folic acid had high inhibitory activity toward the reduction of modified electrode in 0.01 M H 2SO 4. The reduction peak currents were directly proportional to the concentration of folic acid from 1.0 × 10 −8 to 1 × 10 −7 M with correlation coefficient of 0.9976, a detection limit of 1.0 × 10 −10 M of folic acid was estimated. From the inhibitory effect of folic acid on PMo 12-PPy/GCE, the apparent formation constant of folic acid with the modified film was estimated. This modified electrode showed excellent sensitivity and stability for the determination of folic acid. The response mechanism of folic acid at PMo 12-PPy/GCE was discussed in detail.