Ascorbic Acid Sensor Research Articles

Evaluation of electrodeposition synthesis of gold nanodendrite on screen-printed carbon electrode for nonenzymatic ascorbic acid sensor

Gold nanodendrite (AuND) is a type of gold nanoparticles with dendritic or branching structures that offers advantages such as large surface area and high conductivity to improve electrocatalytic performance of electrochemical sensors. AuND structures can be synthesized using electrodeposition method utilizing cysteine as growth directing agent. This method can simultaneously synthesize and integrate the gold nanostructures on the surface of the electrode. We conducted a comprehensive study on the synthesis of AuND on screen-printed carbon electrode (SPCE)-based working electrode, focusing on the optimization of electrodeposition parameters, such as applied potential, precursor solution concentration, and deposition time. The measured surface oxide reduction peak current and electrochemical surface area from cyclic voltammogram were used as the optimization indicators. We confirmed the growth of dendritic gold nanostructures across the carbon electrode surface based on FESEM, EDS, and XRD characterizations. We applied the SPCE/AuND electrode as a nonenzymatic sensor on ascorbic acid (AA) and obtained detection limit of 16.8 μM, quantification limit of 51.0 μM, sensitivity of 0.0629 μA μM−1, and linear range of 180–2700 μM (R2 value = 0.9909). Selectivity test of this electrode against several interferences, such as uric acid, dopamine, glucose, and urea, also shows good response in AA detection.

Fabrication of non-enzymatic and highly sensitive electrochemical ascorbic acid sensor based on GO/Ag/PMMA nanocomposites

In the present study, Graphene Oxide–Silver–Poly(methyl methacrylate) (GO/Ag/PMMA) nanocomposites were fabricated and investigated for Ascorbic Acid sensing without using any enzyme. First, the graphene oxide was prepared by improved Hummers method. The tri-phase nanocomposites were also prepared by sonication and solution casting method with the ratio of Graphene Oxide (1, 2, 3, 4, and 5 %). The composites were characterized by FTIR, X-ray Diffraction (XRD), TGA, and scanning electron microscopy (SEM) analysis. The electrochemical studies/characterizations of ascorbic acid oxidation were carried out in the acidic medium and the new sensor was found to be a better electrochemical ascorbic acid sensor. The fabricated sensor is highly sensitive to ascorbic acid and shows its sensitivity (778.532 µA mM−1 cm−2), it has a broad linear range (from 0.1 to 6 mM), it is selective, and it shows tolerance towards endogenous species such as glucose, uric acid, hydrogen peroxide, and dopamine.

Chemically treated NiCo2O4 nanostructures with boric acid for the development of high-performance electrocatalytic materials for non-enzymatic ascorbic acid sensor

Chemically treated NiCo2O4 nanostructures with boric acid for the development of high-performance electrocatalytic materials for non-enzymatic ascorbic acid sensor

Unveiling the role of heterophase nanostructure in MnO2-based colorimetric sensors for ascorbic acid detection.

Nanozymes based on manganese oxide (MnO2) are demonstrated to be promising probes in colorimetric sensing applications. In this study, the r-MnO2/β-MnO2 heterophase nanostructure was simply prepared by a calcination process with controllable temperature. The characterization of the nanostructured material was confirmed by SEM, UV-vis spectroscopy, Raman, TGA-DSC, and XRD analysis. The r-MnO2/β-MnO2 exhibits a remarkably good catalytic activity in the oxidation process of 3,3',5,5'-tetramethylbenzidine (TMB) compared withthe r-MnO2 or Mn2O3 nanostructure owing to its heterophase junctions. The enhanced performance of the colorimetric sensor for ascorbic acid (AA) detection was investigated using the r-MnO2/β-MnO2 heterophase nanostructure as probe. The r-MnO2/β-MnO2 material enhanced the monitoring of AA in the wide linear range from 1µM to 50μM with alimit of detection of0.84µM. This work presents a promising and straightforward approach for the construction of MnO2-based colorimetric sensor and their practical application in plant growth monitoring.

Keggin type polyoxometalate-based metal-organic frameworks with electrocatalytive activity as effective multifunctional amperometric sensors for metal ions and ascorbic acid

Polyoxometalates (POMs) based metal-organic frameworks (POMOFs) integrate the merits of POMs with excellent redox properties and MOFs with highly ordered porous crystalline structures, which show potential electrochemical applications relying on the synergistic catalytic effect. Here, two new Keggin-type POMOFs [Cd(btbu)2(H2O)2(PMo12O40)] (CUST-636), [Cd(btbu)2(H2O)(SiW12O40)0.5](CUST-638) are synthesized using flexible ligand of 1,4-bis(1,2,4-triazol-1-yl)butane (abbreviated as btbu) as a ligand by hydrothermal method. PXRD, IR, and TG analysis were carried out on CUST-636 and CUST-638. Then, they were prepared into electrode materials (referred to as 636-GCE and 638-GCE), to explore the electrocatalytic properties. 636-GCE and 638-GCE show good electrocatalytic redox performance against KBrO3, KNO2, K2Cr2O7 and AA. Furthermore, detection of trace Cr(VI) was conducted using electrochemical sensors 636-GCE and 638-GCE. The low detection limits (LODs) of CUST-636 and CUST-638 were 0.32 and 0.45 μM, respectively, which were lower concentrations of Cr(VI) in drinking water than the maximum allowable concentration specified by the World Health Organization (WHO).

MOF-derived high-density carbon nanotubes “tentacle” with boosting electrocatalytic activity for detecting ascorbic acid

Accurate detection of ascorbic acid (AA) plays a significant role in food and human physiological processes. Herein, a three-dimensional flexible leaf-like nitrogen-doped hierarchical carbon nanoarrays with high-density carbon nanotube “tentacle” architecture (NC/CNT-Co), which possesses high specific surface area, plenty of active defect sites, and various pore size distributions, was synthesized by the pyrolysis of zeolitic imidazolate framework (ZIF(Co)), while g-C3N4 acted as carbon source and heteroatom doping agent. Benefiting from its unique structure and surface properties, a selective and highly sensitive AA sensor was developed using this material. Compared to powder materials, NC/CNT-Co modified CF (CF@NC/CNT-Co) which don't be extra decorated, exhibits lower detection limit (1 μM), a wider linear range (20–1400 μM), and better stability, showing higher performance in electrocatalysis and detection of AA. Furthermore, CF@NC/CNT-Co also demonstrates high resistance to interference and fouling in AA detection. Particularly, the prepared CF@NC/CNT-Co electrode could determine AA in beverage samples with a recovery rate of 96.3–103.5 %. Therefore, the three-dimensional NC/CNT-Co hierarchical structure can be provided as an original electrode nanomaterial suitable for the selective and sensitive detection of AA, with a wide range of practical applications from food analysis to the pharmaceutical industry.

Rapid redox-response featured visual ascorbic acid sensor based on simple-assembled europium metal-organic framework

A facile, fast and visible sensing platform for ascorbic acid (AA) detection has been developed based on self-assembled hydrangea-like europium metal-organic framework (HL-EuMOF). HL-EuMOF was synthesized through a simple one-step mixing process with Eu3+ and 1, 10-phenanthroline-2, 9-dicarboxylic acid at room temperature, which exhibited excellent properties including strong red fluorescence, long decay lifetime (548.623 μs) and good luminescent stability. Based on the specific redox reaction between Fe3+ and AA, the HL-EuMOF@Fe3+ was fabricated with “turn-off” response for AA, where the resulting Fe2+ displayed effective fluorescence quenching ability toward HL-EuMOF. The sensor demonstrated low detection limit (31.94 nM), rapid response time (30 s) and high selectivity. Integration of smartphone-assisted RGB analysis with HL-EuMOF@Fe3+ permitted convenient and visible quantitative determination of AA level. This approach also presented good detection performances in complex human serum and beverage samples, which could provide a valuable tool for AA detection in biomedical research and food industry.

Highly efficient electrochemical ascorbic acid determination via a cooperative catalytic effect of dendritic Bi/Bi2O3 junctions and oxygen vacancies

This study developed an electrochemical sensor for ascorbic acid (AA) using dendritic nanostructured (DN) bismuth/bismuth oxide thin films with oxygen-deficient (SOD) surfaces (SOD-DN Bi/Bi2O3-x thin films) that were successfully fabricated through electrodeposition on fluorine-doped tin oxide (FTO) substrates. Using cyclic voltammetry and amperometry, we assessed electrocatalytic activity in neutral media. The prepared SOD-DN Bi/Bi2O3-x thin film was used, for the first time, as electrodes in a highly sensitive and selective electrochemical AA sensor. The SOD-DN Bi/Bi2O3-x thin film with optimal characteristics was shown to be ultrasensitive in AA detection in neutral conditions, whereby high detection sensitivity ∼ 2.30 µA µM-1cm−2 over a wide range of AA concentration ∼ 0.01 µM to 1.0 mM and working potential range ∼ 0.3–1.0 V vs. SCE. The results indicate that SOD-DN Bi/Bi2O3-x can provide large amounts of active reaction sites, thereby enhancing electrocatalytic activity and electrochemical sensitivity. Due to this, it is a unique electrochemical sensor able to detect AA without interference from DA, UA, or other contaminants. A further amperometric test demonstrated that this sensor was capable of detecting AA even under conditions of dopamine and uric acid. Accordingly, the proposed sensor provides a promising avenue for developing electrochemical sensing for AA determination. This strategy introduces a novel type of high-efficiency electrocatalyst for ultrasensitive detection of medical and environmental biomarkers.

High performance Pt-anchored MoS2 based chemiresistive ascorbic acid sensor

Ascorbic acid (AA), known as vitamin C, is a vital bioactive compound that plays a crucial role in several metabolic processes, including the synthesis of collagen and neurotransmitters, the removal of harmful free radicals, and the uptake of iron by cells in the human intestines. As a result, there is an absolute need for a highly selective, sensitive, and economically viable sensing platform for AA detection. Herein, we demonstrate a Pt-decorated MoS2 for efficient detection of an AA biosensor. MoS2 hollow rectangular structures were synthesized using an easy and inexpensive chemical vapor deposition approach to meet the increasing need for a reliable detection platform. The synthesized MoS2 hollow rectangular structures are characterized through field effect scanning electron microscopy (FESEM), energy-dispersive spectroscopy elemental mapping, Raman spectroscopy, and x-ray photoelectron spectroscopy. We fabricate a chemiresistive biosensor based on Pt-decorated MoS2 that measures AA with great precision and high sensitivity. The experiments were designed to evaluate the response of the Pt-decorated MoS2 biosensor in the presence and absence of AA, and selectivity was evaluated for a variety of biomolecules, and it was observed to be very selective towards AA. The Pt-MoS2 device had a higher response of 125% against 1 mM concentration of AA biomolecules, when compared to that of all other devices and 2.2 times higher than that of the pristine MoS2 device. The outcomes of this study demonstrate the efficacy of Pt-decorated MoS2 as a promising material for AA detection. This research contributes to the ongoing efforts to enhance our capabilities in monitoring and detecting AA, fostering advancements in environmental, biomedical, and industrial applications.

Novel and Extremely Sensitive NiAl2O4-NiO Nanostructures on an ITO Sensing Electrode for Enhanced Detection of Ascorbic Acid.

The current study focused on the design of an extremely sensitive electrochemical sensor of ascorbic acid based on a mixture of NiAl2O4-NiO nanoparticles that, produced in a single step using the sol-gel method, on an ITO electrode. This new sensing platform is useful for the detection of ascorbic acid with a wide range of concentrations extending from the attomolar to the molar. SEM micrographs show the porous structure of the NiAl2O4-NiO sample, with a high specific surface area, which is beneficial for the catalytic performance of the nanocomposite. An XRD diffractogram confirmed the existence of two phases, NiAl2O4 and NiO, both corresponding to the face-centred cubic crystal structure. The performances of the modified electrode, as a biomolecule, in the detection of ascorbic acid was evaluated electrochemically by cyclic voltammetry and chronoamperometry. The sensor exhibited a sensitive electrocatalytic response at a working potential of E = +0.3 V vs. Ag/Ag Cl, reaching a steady-state current within 30 s after each addition of ascorbic acid solution with a wide dynamic range of concentrations extending from attolevels (10-18 M) to molar (10 mM) and limits of detection and quantification of 1.2 × 10-18 M and 3.96 × 10-18 M, respectively. This detection device was tested for the quantification of ascorbic acid in a 500 mg vitamin C commercialized tablet that was not pre-treated.

Stable Cd(II)-based coordination polymer as a multifunctional fluorescent sensor for ascorbic acid, acetylacetone and nitrofuran antibiotics

The concentrations of hazardous volatile organic compounds (VOCs), pharmaceutical antibiotics and biomolecules in water systems are closely related with public health and ecological security. Thus, the convenient and accurate detection of these harmful items can not only reflect the state of human health but also evaluate the level of homologous contamination in the environment. To this end, a new Cd(II)-CP ({[Cd3L2(bmoe)]·DMF}n) with excellent luminescence properties was designed by employing the semi-rigid tricarboxylic acid 4-(2′,3′-dicarboxylphenoxy) (H3L) and N-donor ligand 1,1′-bis(1H-benzimidazolyl) oxydiethane (bmoe). The as-prepared Cd-CP features the unique uninodal sql topology. Benefiting from its great stability in the aqueous system, Cd-CP serves as a versatile multifunctional fluorescent sensor for different analytes, ascorbic acid (AA), nitrofuran antibiotics nitrofurantoin (NFT) and nitrofurazone (NFZ) and acetylacetone (ACAC). The established methods are characterized with impressive low detection limits, ultrafast response time, high sensitivity, strong anti-interference ability, as well as reliable reproducibility. Experimental and theoretical calculation reveals that the collaborative effects of Förster resonance energy transfer (FRET), inner-filter effect (IFE) and photoinduced electron transfer (PET) are the most probable causes behind the quenching of the CP's fluorescence signal.

A non-enzymatic sensor obtained by direct writing of a AuNP-based ink for monitoring ascorbic acid in sweat

Recently, there has been an increasing interest in the development of wearable sensors for monitoring vitamin C (ascorbic acid) in sweat. These sensors can help assess personal nutritional status, prevent vitamin imbalances, and determine the effectiveness of certain medical treatments. This study presents the first example of non-enzymatic ascorbic acid sensor based on the catalytic activity of printed AuNPs. The three-electrode electrochemical system sensor was fabricated by printing a working and counter-electrode from an AuNP-based ink and a pseudo-reference electrode from a silver ink, on a flexible Kapton® substrate. SEM examination of the printed gold layer revealed a highly divided material, which facilitates electron transfer and accelerates the oxidation of ascorbic acid. In vitro amperometry demonstrated a proportional increase in current with ascorbic acid concentration ranging from 10 to 390 μM, with a sensitivity of 14 μA·mM−1·cm−2. The low oxidation potential of +0.2 V vs Ag/AgCl effectively avoided most interfering oxidations. These results pave the way toward evaluation on the body of healthy volunteers, by placing the sensor directly on their skin, for example for tracking the changes in ascorbic acid concentration in sweat when eating Vitamin C tablets or Vitamin C-containing food such as orange juice. The very first results demonstrated good real-time performance in testing in such experimental conditions. This has potential applications in healthcare, not only on skin but also on therapeutic bandages applied to chronic wounds.

Layer-by-layer growth of Cu3(HHTP)2 films on Cu(OH)2 nanowire arrays for high performance ascorbic acid sensing

Growing three-dimensional (3D) metal organic frameworks (MOFs) via heterogeneous epitaxial growth on metal hydroxide arrays are effective for constructing electrochemical sensor. However, the growth of MOFs is difficult to control, resulting in thick and irregular morphologies and even damage the metal hydroxide template. In this work, Cu3(HHTP)2 (HHTP = 2, 3, 6, 7, 10, 11-hexahydroxytriphenylene) films with controllable thickness and morphology were successfully prepared on Cu(OH)2 nanowire arrays (NWAs) through layer-by-layer (LBL) growth method. We have discovered that the LBL cycle and the reaction solvent composition are crucial for growing homogenous MOF thin films. The Cu3(HHTP)2 based ascorbic acid (AA) sensor, fabricated in ethanol within 10 LBL cycles, generated an ultrahigh sensitivity of 821.64 μA mM−1 cm−2 in the range of 6–981.41 μM, a low detection limit of 60 nM as well as the great selectivity, stability and reproducibility. Moreover, the relative deviation for AA detection in two fruit juices were 3.22 % and 3.71 %, and the test result for human sweat fall within the normal AA concentration range, verifying the feasibility of as-prepared sensor for practical application.

Iron/Iron(III) Oxide Decorated on Electrochemically Reduced Graphene Oxide: a Novel One-Step Electrosynthesis and a Fabrication of an Electrochemical Ascorbic Acid Sensor

Considering on required detection time and sensitivity, electrochemical method is an excellent candidate for ascorbic acid (AA) sensing. We propose using the synergistic effects of iron(0)/iron(III) oxide decorated on the electrochemically reduced graphene oxide (ERGO/Fe-Fe2O3) modified Pt microelectrode as an electrochemical AA sensor using cyclic voltammetry (CV) technique. Herein, ERGO/Fe-Fe2O3 was directly fabricated on the Pt microelectrode using a novel one-step electrosynthesis. Fe-Fe2O3 acts as an oxidized-nanozyme with works as redox centers on the electrode for oxidation of AA. Fe-Fe2O3 nanozymes are immobilized on electrochemically reduced graphene oxide (ERGO), which supports a large electroactive and excellent electrically conductive surface for electron-transfer during electrochemical oxidation of AA. The developed electrochemical sensor allowed for sensing AA in medical samples with high sensitivity in concentration range from 0.05 to 10.00 mM and a limit of detection (LOD) of 5.93 μM.

Straightforward method for the electrochemical identification of dopamine in the presence of uric acid and ascorbic acid

A few-layer graphene/Pt (FGP) electrode and a novel electrochemical technique were used in determining dopamine and simultaneously detecting uric acid (UA), ascorbic acid (AA), and dopamine (DA) in a buffered phosphate-saline solution at pH 7.4. The FGP electrode effectively separated the oxidation peaks of UA, DA, and AA in the positive scan. Interestingly, during the negative scan, the FGP electrode selectively responded to DA while showing negligible response to UA and AA, thus allowing the accurate quantification of small amounts of DA in the presence of considerable UA and AA interferences. The sensors for AA, DA, and UA exhibited successful detection in the positive scan. The linear ranges were 10–1800 (AA), 1–300 (DA), and 5–800 (UA) µM, the sensitivity was 109.27 (AA), 754.19 (DA), and 493.03 (UA) µA cm–2 mM–1, and the detection limits were 4.2 µM (AA), 0.42 µM (DA), and 2.2 µM (UA). Furthermore, DA quantification was achieved in the negative scan, demonstrating a linear range of 1–100 µM, sensitivity of 2235.7 µA cm–2 mM–1, and detection limit of 0.14 µM. This study presents a novel and efficient electrochemical technique for the rapid and straightforward detection of dopamine.

Iridium nanoparticles supported on polyaniline nanotubes for peroxidase mimicking towards total antioxidant capacity assay of fruits and vegetables

In this study, a straightforward approach is presented for the first time to anchor Ir nanoparticles on the surface of uniform polyaniline (PANi) nanotubes (NTs), which can be used as an efficient peroxidase (POD)-like catalyst. The morphology and chemical structure of the PANi-Ir nanocomposite are characterized by scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), X-ray diffractometer (XRD), Raman and X-ray photoelectron spectroscopy (XPS) measurements. Owing to the strong interaction between Ir nanoparticles and PANi, a remarkable catalytic enhancement is achieved compared to the bare Ir black catalyst and individual PANi NTs, dominating withan electron transfer mechanism. Furthermore, an efficient colorimetric sensor for ascorbic acid (AA) is developed with a low detection limit of 1.0 μM (S/N = 3), and a total antioxidant capacity (TAC) sensing platform is also constructed for the rigorous detection and analysis of fruits and vegetables.

A novel “On-Off” colorimetric sensor for ascorbic acid and hydrogen peroxide based on peroxidase activity of CeO2/Co3O4 hollow nanocubes

The development of artificial nanostructured enzymes has garnered significant interest in the field of nanobiotechnology due to the distinct advantages. In this work, CeO2/Co3O4 hollow nanocubes (named as CeO2/Co3O4 HNs) with exceptional peroxidase-like activity have been prepared employing ion exchange and subsequent calcination process. In the presence of hydrogen peroxide (H2O2), the CeO2/Co3O4 HNs display high peroxidase-like activity, catalyzing the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) and resulting in a color change from transparent to blue. The oxidized TMB (ox-TMB) is subsequently reduced to TMB due to the reducibility of ascorbic acid (AA), restoring the original color of solution. Consequently, a straightforward and efficient "On-Off" colorimetric sensor has been established for the accurate detection of H2O2 and AA, with detection limits (LOD) of 3.56 and 0.179 μM, respectively. In summary, the prepared colorimetric sensor offers numerous advantages, including ease of operation, cost-effectiveness, rapid response, and effective visual monitoring, which holds substantial promise for applications in detection of hydrogen peroxide and ascorbic acid.

A facile fluorescence Eu MOF sensor for ascorbic acid and ascorbate oxidase detection.

In this work, a facile fluorescence Eu3+-based metal-organic framework (Eu MOF) sensor for ascorbic acid (AA) and ascorbate oxidase (AAO) detection was developed. The fluorescence of the Eu MOF could be effectively quenched by Ce3+ but not by Ce4+ at an appropriate concentration, and thus, when the reductant AA was added into the solution containing Ce4+, Ce4+ was chemically reduced to Ce3+, which induced the decreased fluorescence signal of the Eu MOF. However, when AAO was introduced, AA was effectively oxidized to dehydroascorbic acid (DHAA) under the catalysis of AAO, and thus, Ce4+ could not be reduced, resulting in the fluorescence restoration of the Eu MOF. Hence, the concentration of AA and AAO could be determined by the fluorescence decrease and restoration of the Eu MOF. The fluorescent platform showed high sensitivity with a limit of detection of 0.32 μM for AA and 1.18 U L-1 for AAO, respectively. Moreover, the proposed method was successfully applied for AA and AAO determination in real samples, indicating great potential for biomedical application in complex matrices.

Modulation of copper sites in porphyrin metal-organic frameworks for electrochemical ascorbic acid sensing.

Two metal-organic frameworks (MOFs) with different Cu-centered coordination structures were synthesized. By introducing 4,4-bipyridine as a linker in the Cu-MOFs, we have discovered that Cu-O, instead of Cu-N, is the active site with higher electrocatalytical activity towards ascorbic acid, which is essential to understand and develop Cu-based ascorbic acid sensors.

A fluorescence “turn-on” sensor for ascorbic acid in fruit juice and beverage based on ascorbate oxidase-like activity of citric acid-derived carbon dots

Citric acid-derived carbon dots (CA-CDs) without any modifications were found to have the ascorbate oxidase (AAO)-like activity. The CA-CDs have high affinity for ascorbic acid (AA), which is similar to natural AAO. The robustness of CA-CDs is greater than that of AAO. Based on the AAO mimetic activity of CA-CDs, a sensitive turn-on mode and natural enzyme-free fluorescence detection method has been developed for AA in some fruit juice and beverage samples with satisfied recoveries. This study provides CDs-based AAO mimetic nanozymes to replace the expensive natural enzymes or heavy metal-based nanozymes, which will show great potential in biological and food assays.