Electrochemical Determination Of Ascorbic Acid Research Articles

Integrated tetrahydroxyphthalocyanine-coated graphene decorated with ionic liquid-functionalized gold nanoparticles for highly sensitive and selective electrochemical determination of ascorbic acid in fruit juices.

Surface functionalization and the combined utilization of zero-dimensional and two-dimensional nanomaterials is an effective method to achieve highly sensitive detection for electrochemical analysis. Using an all-in-one strategy, phthalocyanine, gold nanoparticles, and ionic liquid were successively modified on the graphene surface as a highly integrated electrode modification material. Phthalocyanine can repair the defects of reduced graphene oxide by binding to the graphene structure surface through non-covalent functionalization. The combination of ionic liquid on the surface of gold nanoparticles can enhance their physical and chemical activity while preserving their stability. The obtained phthalocyanine-coated graphene nanosheets decorated with ionic liquid-functionalized gold nanoparticles nanocomposites had enhanced electrocatalysis and conductivity ability, and were used for highly sensitive electrochemical detection of ascorbic acid in fruit juices. Excellent results were obtained for the detection of ascorbic acid in thelinear range 0.05 to 50µmol/L with a detection limit of 6.80nmol/L (S/N = 3) and a sensitivity of 2.68μA μM-1cm-2, indicated that the proposed sensor strategy with multiple signal amplification can achieve higher detection sensitivity. Furthermore, the sensor was used to quantify ascorbic acid content in grapefruit and orange juice with good selectivity and accuracy. The highly integrated electroactive nanocomposites construction method described may also be used with other electrode modification materials and is anticipated to yield fresh perspectives on the advancement of ultrasensitive detection.

Electrochemical determination of ascorbic acid using palladium supported on N-doped graphene quantum dot modified electrode

To precise screening concentration of ascorbic acid (AA), a novel electrochemical sensor was prepared using palladium nanoparticles decorated on nitrogen-doped graphene quantum dot modified glassy carbon electrode (PdNPs@N-GQD/GCE). For this purpose, nitrogen doped GQD nanoparticles (N-GQD) were synthesized from a citric acid condensation reaction in the presence of ethylenediamine and subsequently modified by palladium nanoparticles (PdNPs). The electrochemical behavior of AA was investigated, in which the oxidation peak appeared at 0 V related to the AA oxidation. Considering the synergistic effect of Pd nanoparticles as an active electrocatalyst, and N-GQD as an electron transfer accelerator and electrocatalytic activity improving agent, PdNPs@N-GQD hybrid materials showed excellent activity in the direct oxidation of AA. In the optimal conditions, the voltammetric response was linear in the range from 30 to 700 nM and the detection limit was calculated to be 23 nM. The validity and the efficiency of the proposed sensor were successfully tested and confirmed by measuring AA in real samples of chewing tablets, and fruit juice.

Electrochemical Deposition of Reduced Graphene Oxide Decorated with Silver and Nickel Oxide Nanoparticles for Quantification of Ascorbic Acid in Bottled Fruit Juice and Vitamin C Tablet

Because of its simplicity of evaluation, ability to detect the lowest quantities, and convenience of operation, electrochemical determination of ascorbic acid is gaining popularity. The high sensitivity, selectivity, and low cost, nanosensors have gained enourmous attention in recent years for the detection of active pharmacological compounds and food pollutants. Ni and Ni-containing compounds have a favorable affinity for a number of organic functional groups such as -thio, -hydroxyl, -carboxyl, and -amine. However, its poor conductivity hinders its electrochemical performance. Hence, the procedures for improving the conductivity of metal oxides that are incredibly good studies query to meet the desired level of detection. We devised a straightforward method for concurrently synthesizing silver and nickel oxide nanoparticles on reduced graphene oxide using electrochemical deposition method on a glassy carbon electrode (GCE). The electrodeposited materials were scratched from GCE and characterized for Raman, SEM/EDS, EIS, and XPS. The materials produced after deposition were examined also for Ascorbic Acid (AA) detection in bottled fruit juice and Vitamin C tablets yielded 0.457 μM limits of quantification and 100.61% and 99.40% average recoveries, respectively.

Electrochemical Determination of Ascorbic Acid by Mechanically Alloyed Super Duplex Stainless Steel Powders

SAF-2507 super duplex stainless steel powders (SDSS) were prepared using a high-energy planetary ball milling process. The X-ray diffraction (XRD) shows peak broadening after 20 h of ball milling and revealed a phase transformation resulting in a two-phase alloy mixture containing nearly equal amounts of ferrite (α) and austenite (γ). After 20 h of ball milling the particle size was reduced to ~201 nm. Scanning electron microscope (SEM) micrographs showed small-size irregular grains with an average particle size ranging from 5–7 µm. The high-resolution transmission microscope (HRTEM) analysis confirmed the presence of nanocrystalline particles with sizes ranging from 10 to 50 nm. The presence of ferrite phase is visible in the corresponding diffraction pattern as well. In this paper, we have discussed the electrochemical sensor application of mechanically alloyed nano-structured duplex stainless steel powders. The fabricated 4 mg duplex stainless steel modified carbon paste electrode (SDSS-MCPE) has shown excellent current sensitivity in comparison with 2, 6, 8, and 10 mg SDSS-MCPEs during the detection of ascorbic acid (AA) in a phosphate buffer solution with a pH of 6.8. The calculated electrode active surface area of SDSS-MCPE was found to be almost two times larger than the surface area of the bare carbon paste electrode (BCPE). The limit of detection (LD) and limit of quantification (LQ) were found to be 0.206 × 10−8 M and 0.688 × 10−8 M, respectively, for the fabricated 4 mg SDSS-MCPE.

Sensor performances of novel piperidine substituted cobalt(II) and copper(II) phthalocyanines for detection of dopamine, ascorbic acid and uric acid

Peripherally and non-peripherally tetra substituted cobalt(II) and copper(II) phthalocyanines were prepared and characterized via spectroscopic techniques. The electrochemical characterization of metallo-phthalocyanines were carried out to determine electrochemical behaviors. Electrochemical results of complexes were supported with the in-situ spectroelectrochemical measurements. Complexes having piperidine functional groups were electropolymerized on glassy carbon electrode surface. Sensor performances were investigated toward ascorbic acid, dopamine, uric acid. Non-peripheral cobalt(II) phthalocyanine exhibited a good linear relation in the concentration range of 1.4–60 µM with sensitivity of 0.49 µAµM−1 and low detection limit of 0.92 µM for electrochemical determination of ascorbic acid. Non-peripheral copper(II) phthalocyanine demonstrated high sensitivity (0.52 and 1.31 µAµM−1) and low detection limit (1.92 and 2.61 µM) especially for ascorbic acid and uric acid, respectively.

Design and implementation of low-cost portable potentiostat based on WeChat

The potentiostat is critical in the development of electrochemical systems; however, its cumbersome detection and high cost considerably limit its large-scale application. To provide an affordable alternative to developing countries and resource-constrained areas, this study designs an electrochemical detection system based on smartphones, which uses Bluetooth Low Energy to convert open-source potentiostat data based on PSoC-5LP. The WeChat application on the smartphone provides an interface for entering experimental parameters and visualizing the results in real time. The smartphone-based electrochemical detection system has a simple design and reduces the size (10?3?0.3 cm3) and the cost of the hardware ($ 18). The system performs the most commonly used cyclic voltammetry for electrochemical detection, with results that are comparable to those obtained using a commercial potentiostat and an error rate of 1.3 %. In the classical teaching experiment of electrochemical determination of ascorbic acid in orange juice samples, the measured value of the system is 0.367?0.012 mg/mL, compared with the standard reference value of 0.37 mg/mL, which is obviously a convincing value. Therefore, this system is a low-cost, reliable alternative to a potentiostat for research, education or product integration development.

Metal-organic framework-derived porous ternary ZnCo2O4 nanoplate arrays grown on carbon cloth for simultaneous electrochemical determination of ascorbic acid, dopamine, and uric acid.

Metal-organic frameworks derived from ternary metal oxide directly grown on the conductive substrate have attracted great interest in electrochemical sensing. In this work, metal-organic framework-derived ternary ZnCo2O4 nanoplate arrays that were grown on carbon cloth (ZnCo2O4 NA/CC) are fabricated and applied for the electrochemical determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). Field emission scanning electron microscope (FESEM) reveals that a network-like CC substrate is covered with considerable nanoplate arrays, presenting a large specific area. X-ray photoelectron spectroscopy (XPS) demonstrates the nanoplate arrays to be composed of ZnCo2O4. Benefiting from the unique array morphology and ternary element composition, the ZnCo2O4 NA/CC shows desirable performances for simultaneous detection of AA, DA, and UA. The individual detection limits are 7.14 μM for AA, 0.25 μM for DA, and 0.33 μM for UA. Additionally, the ZnCo2O4 NA/CC is successfully applied for the quantitative determination of AA, DA, and UA in spiked serum samples, showing its great application potential.

Transfer of multivariate calibration model for simultaneous electrochemical determination of ascorbic acid and uric acid

Transfer of multivariate calibration model for simultaneous electrochemical determination of ascorbic acid and uric acid

In-situ growth of Cu@CuFe Prussian blue based core-shell nanowires for non-enzymatic electrochemical determination of ascorbic acid with high sensitivity and reusability

• Core-shell nanowires of Cu@PBA was in-situ fabricated via a novel electrodeposition route. • Cu provided high electrocatalysis and electron transfer rate and was protected by PBA. • The as-prepared AA sensor showed an ultra-low detection limit and ultra-wide linear range. • Excellent anti-interference ability and stability support its practical applications. Ascorbic acid (AA) is an important deoxidizer contained in food, drink and medicine. However, existing detection methods are time-consuming and complex to industrial production and quality testing. Here, we proposed a core–shell nanowires constructed electrochemical sensor to achieve the highly sensitive and selective recognition of AA with a long-term reusability. Cu nanowires with 30 nm diameter were served as both structure skeleton and reactant to induce in-situ growth of Cu-Fe Prussian blue layer with 10 nm thickness covering its surface to form a core–shell architecture. This nanocomposite couples advances of Cu and Prussian blue to possess both high electrocatalysis and conductivity. The as-prepared sensor shows an excellent sensitivity with an ultrawide linear range, together with the remarkable reusable ability during 30 days with 300 times of repetitive detection. Used for four kinds of juice and bear as real samples, this sensor can accurately reported AA concentration within 5 s.

A high efficiency N, P doped porous carbon nanoparticles derived from lotus leaves for simultaneous electrochemical determination of ascorbic acid, dopamine, and uric acid

A kind of phosphorus doped nitrogenous porous carbon material (CNP) has been prepared from lotus leaves to fabricate a novel electrochemical sensor for the simultaneous determination of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Detailed characteristics of the as-prepared porous carbon were investigated by SEM, BET, XPS, XRD and Raman analysis. The electrochemical behaviors of the modified electrode were explored by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The CNP/GCE demonstrated linear response ranges of 20 μM–250 μM for AA, 10 μM–480 μM for DA, and 25 μM–2500 μM for UA, with detection limits (S/N = 3) of 4.25 μM, 0.86 μM, and 0.20 μΜ, respectively. Furthermore, the CNP/GCE has been successfully applied to determine AA, DA and UA in real serum samples, which exhibited excellent reproducibility, anti-interference and stability.

Metal-free graphene-based nanoelectrodes for the electrochemical determination of ascorbic acid (AA) andp-nitrophenol (p-NP): implication towards biosensing and environmental monitoring

Herein, tyramine functionalized graphene oxide electrocatalyst is used for the electrochemical determination of ascorbic acid and p-nitrophenol in 1 M phosphate buffer solution at pH-7 with long term current/potential stability and reproducibility.

Holey nitrogen-doped graphene aerogel for simultaneously electrochemical determination of ascorbic acid, dopamine and uric acid

In this paper, holey nitrogen-doped graphene aerogel (HNGA) was synthesized and applied to the concurrently electrochemical determination of small biological molecules including ascorbic acid (AA), dopamine (DA) and uric acid (UA). Firstly, holey graphene hydrogel was synthesized by the hydrothermal reaction in the presence of H2O2, which subsequently was lyophilized and further annealed in the mixed gas of ammonia and argon to obtain HNGA. Electron microscopy characterization exhibited a great number of nanopores formed on the basal surface of graphene sheets, and HNGA possessed a hierarchically porous structure. The unique structure and composition of HNGA make it an ideal material for electroanalytical application through accelerating mass and electron transfer. HNGA modified glassy carbon electrode (HNGA/GCE) displayed significantly enhanced electrochemical response to AA, DA, and UA, namely reducing overpotential, increasing current density, and improving the reversibility. The oxidation peaks of these three biomolecules can be entirely separated with evident peak potential differences which are 0.216 V (AA-DA), 0.120 V (DA-UA), and 0.336 V (AA-UA), which it allowed the determination of the three substances at the same time. This sensor shows high sensitivity for the determination of AA, DA, and UA with the detection limit of 16.7 μM, 0.22 μM, and 0.12 μM (S/N = 3), respectively. The proposed sensor was applicable for the practical sample analysis as well and desirable recovery was obtained.

Application of carbon nanoonion-NiMoO4-MnWO4 nanocomposite for modification of glassy carbon electrode: Electrochemical determination of ascorbic acid

In this paper, sonochemical synthesized nanocomposite was used in the construction of an electrochemical sensor. Decorated carbon nanoonions (CNOs) with nickel molybdate (NiMoO4) and manganese tungstate (MnWO4) nanocomposite were used to modify the glassy carbon electrode (GCE). The high conductivity and large surface area of the CNOs and the electrocatalytic effect of NiMoO4 and MnWO4 nanocomposite provide a synergistic effect on the electrooxidation processes. The modified GCE surface with a synthesized nanocomposite of CNO-NiMoO4-MnWO4 was used to determine ascorbic acid using differential pulse voltammetry (DPV) method. The developed ascorbic acid sensor displayed a wide dynamic calibration range (1–100 μM) with trace level LOD (0.33 μM) and appropriate sensitivity (0.1768 μA μM−1cm−2). The determination of ascorbic acid in the serum and urine as the real samples exhibited a reasonable relative recovery in the range of 100–104%.

L-Cysteine/Graphene oxide for electrochemical determination of ascorbic acid in the presence of dopamine and uric acid

Ascorbic acid (AA), also known as vitamin C, has many roles in biological systems, such as prevention of cancer and common cold. Determination of AA is essential for food and pharmaceutical industries. Nowadays, electrochemical method is a potential method for detecting AA. However, detection of AA in presence of biological compounds, e.g. dopamine (DA) and uric acid (UA), is big challenge because these compounds are commonly found in biological samples and interfere the oxidation peak potential of AA. To overcome this problem, electrochemical coating of cysteine on graphene oxide decorated screen-printed electrode (Cys/GO/SP) was newly used for determination of AA. Field emission scanning electron microscope, energy dispersive x-ray and EIS were used to characterize the composites. AA of different concentrations were determined in phosphate buffer saline that has 10-µM DA and 10-µM UA using by differential pulse voltammetry (DPV). Cys/GO/SP presented three oxidation peaks corresponding to AA, DA and UA, whereas GO/SP and SP provided single peak. The oxidation peak currents of AA showed good linear relationship with AA concentrations of 0.5 - 5 mM with the detection limit of 0.26 mM. The results suggest that Cys/GO/SP can be used for electrochemical determination of AA in the interference of DA and UA.

A low cost, versatile and chromatographic device for microfluidic amperometric analyses

Microfluidic devices provide an interesting alternative to analytical tests, allowing the reduction in the use of mobile phases, solutions and generation of chemical residues, cost of analysis and simplification of operations. However, there is a problem often not addressed: while inexpensive, the electrochemical microfluidic systems require a commercial potentiostat, making it difficult and expensive their use outside of the laboratory. Here, we describe a cheap (approximately 40 dollars) Arduino-based miniaturized electronic system (with data transmission by USB connection to computer or via Bluetooth to smartphone) integrated with a 3D-printed platform and microfluidic thread-based electroanalytical device to support three different electrodes: graphite electrodes for the determination of uric acid (UA); carbon-printed electrode to quantify hydrochlorothiazide (HCZ); and gold electrodes sputtered into the microfluidic channel for the chromatographic separation and electrochemical determination of ascorbic acid (AA) and epinephrine (EP). A comparison of electrochemical signals obtained using a commercial potentiostat and our system yielded similar results: differences between peak signals were no more than 6.1%. Using our proposed system, a linear range of 5.0–1000.0 μM for UA, 5.0–750.0 μM for HCZ and 100.0–2500.0 μM for both AA and EP was obtained, in addition to a detection limit (LOD) of 1.1 μM for UA, 1.1 μM for HCZ, 6.8 μM for AA and 5.3 μM for EP. Thus, the proposed system was successfully applied in three different situations and showed good analytical performance, similar with the commercial potentiostat but at a much lower cost, fully portable and autonomous.

Composites of Bimetallic Platinum-Cobalt Alloy Nanoparticles andReduced Graphene Oxide for Electrochemical Determination of Ascorbic Acid, Dopamine, andUric Acid

The ultimate aim of this study is to produce a composite of bimetallicplatinum-cobalt nanoparticles and reduced graphene oxide (Pt-Co@rGO) based biosensorfor the detection of ascorbic acid (AA), dopamine (DA) and uric acid (UA). Those arebiologically important molecules with the key functions for the human body.Pt-Co@rGO was synthesized using a microwave-assisted technique and utilized for theproduction of a highly sensitive and stable electrochemical biosensor. Detailedspectral XPS and Raman analysis, XRD, and TEM/HR-TEM characterization were alsostudied. Due to the superior activity and excellent conductivity of rGO,well-separated oxidation peaks of these biomolecules is proven by DPV (differentialpulse voltammetry) and CV (cyclic voltammetry) measurements. The preparedPt-Co@rGO-based biosensor showed high electrochemical activity, a broad linearresponse, high sensitivity, and acceptable limit of detection values for individualand simultaneous determination of AA, DA, and UA, under optimized conditions. Thelinear range of Pt-Co@rGO was found to be 170–200; 35–1500 and 5–800 µM for AA, DA,and UA, respectively. Moreover, the detection limit of the prepared composite wascalculated as 0.345; 0.051; 0.172 µM for AA, DA, and UA, respectively. In the fieldof electrochemical biosensors, Pt-Co@rGO based sensor is highly promising due to itssuperior sensitivity and good selectivity properties.

Voltammetric simultaneous determination of ascorbic acid and acetaminophen based on graphite screen printed electrode modified with a La3+-doped ZnO nanoflowers

In this work, an easy method was employed to successfully develop La3+-doped ZnO nanoflowers and guar-gum (GG) modified screen printed electrode (La3+/ZnO/GG/SPE), and La3+/ZnO/GG/SPE was applied for the electrochemically detection of ascorbic acid (AA). The electrochemical methods, such as cyclic voltammetry (CV), chronoamperometry (CHA) and differential pulse voltammetry (DPV) were used to evaluate the electrochemical performances toward ascorbic acid on the La3+/ZnO/GG/SPE. Good linearship was observed for ascorbic acid in the ranges of 1.0–700.0 µM, with the detection limits of 0.03 µM. Moreover, this sensor proved favorable to simultaneously determine ascorbic acid and acetaminophen. Finally, the modified electrode has fairly good performance during the employment of real sample analysis to determine the content of ascorbic acid. These results indicate that the La3+-doped ZnO nanoflowers are supposed to be a promising material in the electrochemical determination of ascorbic acid and acetaminophen in real samples.

Synthesis of CeO2/reduced graphene oxide nanocomposite for electrochemical determination of ascorbic acid and dopamine and for photocatalytic applications

In this study, the CeO2/reduced graphene oxide (rGO) nanocomposite was synthesized by a facile hydrothermal method. Structure and morphology of the synthesized nanocomposite were characterized by X-ray diffraction and scanning electron microscopy. Raman spectroscopy and X-ray photoelectron spectroscopy were used to quantify the concentration of oxygen vacancies. Compared with the bare glassy carbon electrode (GCE) and CeO2-modified GCE, the CeO2/rGO electrode exhibited an excellent electrochemical activity toward the oxidation of ascorbic acid and dopamine. Increased concentration of oxygen vacancies coupled with the introduction of rGO as a matrix in the composite resulted in the improvement of the conductivity of the nanocrystals, thereby leading to a faster charge transfer. The photocatalytic properties of CeO2 and CeO2/rGO nanocomposite were evaluated using the degradation of methylene blue under UV–vis light irradiation. Degradation rate constant was determined to be 0.0011 min−1 and 0.0035 min−1 with CeO2 and CeO2/rGO photocatalyst, respectively. The CeO2/rGO nanocomposite exhibited a significant increase in the photoactivity compared with CeO2 because of the unique properties of rGO in suppressing the recombination of photogenerated charge carriers.

Platinum nanoparticles–decorated graphene-modified glassy carbon electrode toward the electrochemical determination of ascorbic acid, dopamine, and paracetamol

In the present study, we report the synthesis and characterization of platinum nanoparticles decorated graphene (GPtNPs) nanocomposite toward the electrochemical determination of ascorbic acid (AA), dopamine (DA), and paracetamol (PCT). GPtNPs demonstrated synergistic catalytic activity with enhanced currents in all of the measurements when compared with graphene-modified glassy carbon electrode (G-GCE) and bare GCE. The nanocomposite exhibited low overpotential for AA oxidation and good peak-to-peak separation of 218.0, 218.0, and 436.0 mV for AA–DA, DA–PCT, and AA–PCT, respectively. Cyclic voltammetry (CV) and chronoamperometry (CA) determination of AA, DA, and PCT showed wide linearity ranges. CV determination of AA exhibited linearity range from 300 μM to 20.89 mM and from 22.02 to 39.87 mM. DA determination using CV exhibited linearity range from 5 to 104 μM and from 114 to 684 μM, whereas CA determination of PCT showed a linearity range from 20 μM to 6.43 mM. Differential pulse voltammetry determinations of AA, DA, and PCT exhibited low detection limits of 300, 5, and 5 μM, respectively.

Electrochemical determination of ascorbic acid, uric acid and folic acid using carbon paste electrode modified with novel synthesized ferrocene derivative and core–shell magnetic nanoparticles in aqueous media

2‐(4‐Ferrocenyl‐1,2,3‐triazol‐1‐yl)‐1‐(naphthalen‐2‐yl)ethanone (2FTNE) and magnetic core–shell manganese ferrite nanoparticles (CMNP) were fabricated and applied to produce a modified carbon paste electrode (CPE). The electrochemical behaviour of ascorbic acid (AA) was investigated using cyclic voltammetry and measured by square wave voltammetry along with that of uric acid (UA) and folic acid (FA). The 2FTNECMNP‐modified CPE (2FTNECMNPPE) had electrocatalytic activity towards AA oxidation that was greater than that of bare CPE and CMNP‐modified CPE. Based on the results, the linear oxidation peak current was 0.01–60 μM for AA level and the correlation coefficient was 0.9997. According to three times the standard deviation for the blank, the limit of detection was calculated as 0.002 μM. Our results showed an increase in selectivity, stability and reproducibility for 2FTNECMNPPE, which significantly could measure AA, UA and FA levels in AA ampoule, FA tablet and urine samples. It can be concluded that 2FTNECMNPPE has promising capacity in the development of electrochemical sensors.