Colorimetric Detection Of Ascorbic Acid Research Articles

Active site-tuned high peroxidase-like activity nanozyme for on-the-spot detection of saliva total antioxidant capacity using smartphone devices

Metal-Organic Framework (MOF) based nanozymes with clear structure are beneficial for exploration of structural-performance and exhibit broad prospects in improving activity. In this study, the prepared bimetallic Fe3Ni-MOF nanozyme was superior to single metal MOF in the peroxidase-like activity. Subsequently, a derivative nanozyme (Fe3Ni-MOF-Ar) was prepared by pyrolysis using Fe3Ni-MOF as the precursor in argon atomoshere with controlled temperature. The investigated of Fe3Ni-MOF-Ar revealed that the irregular macroporous state and the presence of heterovalent FeIII/FeII sites of Fe3Ni-MOF-Ar enable the retention, exposure, and electronic structure regulation of active sites, promoting the dual mechanism (the generation of •OH and electron transfer mechanism) and significantly increasing the peroxidase-like activity. Fe3Ni-MOF-Ar exhibited a strong affinity for substrate H2O2, which is higher than horseradish peroxidase. Ascorbic acid and cysteine are typical substances of antioxidants. Fe3Ni-MOF-Ar was used for sensitive colorimetric detection of ascorbic acid and cysteine, and the detection limit was as low as 150 and 60 nM. In addition, the smartphone devices was used to detection of antioxidant equivalent ascorbic acid, with a detection range of 0.5–120 μM. Fe3Ni-MOF-Ar nanozyme is feasible for sensitive detection of saliva total antioxidant capacity.

Peroxidase activity of a Cu-Fe bimetallic hydrogel and applications for colorimetric detection of ascorbic acid.

A Cu-Fe bimetallic hydrogel (2-QF-CuFe-G) was constructed through a simple method. The 2-QF-CuFe-G metallohydrogel possesses excellent peroxidase-like activity to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) in the presence of H2O2. The catalytic mechanism was confirmed by the addition of •OH radical scavenger isopropyl alcohol (IPA), tert-butyl alcohol (TBA) and ˙OH trapping agent terephthalic acid (TA). Remarkably, the resultant blue ox-TMB system can be used to selectively and sensitively detect ascorbic acid (AA) with an LOD of 0.93 μM in the range of 4-36 μM through the colorimetric method. Moreover, the assay based on the 2-QF-CuFe-G metallohydrogel can be successfully applied to detect AA in fresh fruits.

Single-atom Fe nanozymes with excellent oxidase-like and laccase-like activity for colorimetric detection of ascorbic acid and hydroquinone

Single-atom Fe nanozymes with excellent oxidase-like and laccase-like activity for colorimetric detection of ascorbic acid and hydroquinone

Metalloporphyrin-based Amphiphilic Porous Organic Polymer with Peroxidase-mimetic Activity for Colorimetric Detection of Ascorbic Acid

Metalloporphyrin-based Amphiphilic Porous Organic Polymer with Peroxidase-mimetic Activity for Colorimetric Detection of Ascorbic Acid

Rapid and sensitive colorimetric detection of ascorbic acid using carboxymethyl cellulose functionalized Co3O4 nanoparticles as peroxidase mimic

Rapid and sensitive colorimetric detection of ascorbic acid using carboxymethyl cellulose functionalized Co3O4 nanoparticles as peroxidase mimic

Nitrogen-doped porous carbon nanomaterials synthesized using a magadiite template as efficient peroxidase mimics for colorimetric detection of ascorbic acid as an antioxidant.

Nanomaterials with intrinsic enzyme-like activity have gained substantial scientific attention as viable substitutes to natural biological enzymes owing to their cheap price and great stability. Numerous artificial enzyme mimics have been employed effectively in sectors such as sensing, environmental processing, and cancer treatment. In this study, novel nitrogen-doped porous carbon nanomaterials (CPs) were produced by modifying polypyrrole with magadiite using chemical oxidative polymerization and calcination methods. The obtained nitrogen-doped porous carbon nanomaterials exhibited improved peroxidase-like activity, which catalyzed the oxidation of 3,3,5,5-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2) to produce colorful compounds. Kinetic investigation revealed that the affinity for TMB of nitrogen-doped porous carbon peroxidase mimics was higher than that of genuine horseradish peroxidase (HRP). In addition, a sensitive assay with encouraging performance for the colorimetric detection of ascorbic acid (AA) was successfully fabricated employing nitrogen-doped porous carbon nanomaterials as peroxidase mimics. The results were satisfactory and demonstrated its potential application in antioxidant detection.

Rational design of three-in-one Pt/MnO2/GO hybrid nanozyme with enhanced catalytic performance for colorimetric detection of ascorbic acid and cysteine

In this work, a novel three-in-one Pt/MnO2/GO hybrid nanozyme with wide pH and temperature working range was rational prepared using simple hydrothermal and reduction strategy. The prepared Pt/MnO2/GO displayed enhanced catalytic activity than single active component due to the excellent conductivity of GO, the increased active sites, the increased electron transfer capacity, the synergistic effect between each component and the decreased binding energy for adsorbed intermediates. Combing chemical characterization and theoretical simulation calculations, the O2 reduction process on the Pt/MnO2/GO nanozymes and the generated reactive oxygen species in the nanozyme-TMB system were thoroughly illustrated. Based on the excellent catalytic activity of Pt/MnO2/GO nanozymes, a colorimetric strategy was proposed to detect the ascorbic acid (AA) and cysteine (Cys), and the experimental results indicated that detection range of AA was 0.35–56 μM with a LOD of 0.075 μM and detection range of Cys was 0.5–32 μM with a LOD of 0.12 μM. Good recoveries were achieved in the human serum and fresh fruit juice detection procedures, demonstrating the potential applications of Pt/MnO2/GO-based colorimetric strategy in complex biological and food samples.

A robust and facile label-free method for highly sensitive colorimetric detection of ascorbic acid in fresh fruits based on peroxidase-like activity of modified FeCo-LDH@WO3 nanocomposite

Many compounds such as amino acids and oligonucleotides have been shown to effectively change peroxidase-like activity of nanoparticles. While a few studies have focused on mimicking the active site of natural enzymes on nanozymes and thus increasing their substrate affinity. Therefore, in this work, the surface of FeCo@WO3 nanocomposite was modified using guanosine triphosphate (GTP) to mimic the histidine of peroxidase enzyme's active site and its modification was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Fourier-transform infrared spectroscopy (FT-IR). Then, the peroxidase-mimicking activity of the modified nanocomposite was tested using a colorimetric method, based on the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) in the presence of hydrogen peroxide (H2O2). It was found that GTP improves the activity of FeCo@WO3 as a natural peroxidase active site's distal histidine residue. Ascorbic acid (AA) is a powerful antioxidant that induces the reduction of blue color (oxidized TMB) ox-TMB to colorless TMB. The colorimetric method was applied for the sensitive detection of AA in common fruits. The linear range of AA was 10–100 μM with a limit of detection (LOD) of 0.27 μM, which provides a rapid and sensitive method for testing AA in the field of food analysis.

Mn3O4 nanoparticles decorated porous reduced graphene oxide with excellent oxidase-like activity for fast colorimetric detection of ascorbic acid.

Mn3O4 nanoparticles composed of porous reduced graphene oxide nanosheets (Mn3O4@p-rGO) with enhanced oxidase-like activity were successfully fabricated through an in-situ approach for fast colorimetric detection of ascorbic acid (AA). The residual Mn2+ in the GO suspension of Hummers method was directly reused as the manganese source, improving the atom utilization efficiency. Benefiting from the uniform distribution of Mn3O4 nanoparticles on the surface of p-rGO nanosheets, the nanocomposite exhibited larger surface area, more active sites, and accelerated electron transfer efficiency, which enhanced the oxidase-like activity. Mn3O4@p-rGO nanocomposite efficiently activate dissolved O2 to generate singlet oxygen (1O2), leading to high oxidation capacity toward the substrate 3,3',5,5'-tetramethylbenzidine (TMB) without the extra addition of H2O2. Furthermore, the prominent absorption peak of the blue ox-TMB at 652nm gradually decreased in the presence of AA, and a facile and fast colorimetric sensor was constructed with agood linear relationship (0.5-80μM) and low LOD (0.278μM) toward AA. Owing to the simplicity and excellent stability of the sensing platform, its practical application for AA detection in juices has shown good feasibility and reliability compared with HPLC and the 2, 4-dinitrophenylhydrazine colorimetric method. The oxidase-like Mn3O4@p-rGO provides a versatile platform for applications in food testing and disease diagnosis.

Highly efficient carbon supported Co–Ir nanozyme for the determination of total antioxidant capacity in foods

Nanozyme–based colorimetric assays have aroused extensive attention in biosensing due to quick response, low cost and simplicity. However, their practical applications are limited by the unsatisfactory stability and catalytic activity of nanozymes in complex detection environments. Herein, using the one–pot chemical vapor deposition method, we successfully prepare a highly efficient and stable carbon supported Co–Ir nanozyme (termed as Co–Ir/C nanozyme) for the determination of total antioxidant capacity (TAC) in food samples. The Co–Ir/C nanozyme shows excellent durability under extensive pH ranges, high temperature and high salt concentration due to the protection of carbon supporter. It can be recycled by simple magnetic separation, and its catalytic activity remains stable after long–term operation and storage. Taking full advantage of the superior peroxidase–like activity of Co–Ir/C nanozyme, it is used for colorimetric detection of ascorbic acid (or known as vitamin C), an important vitamin to adjust body's normal physiological function, with results showing higher sensitivity (detection limit of 0.27 μM) than most of the recently published works. Moreover, the determination of TAC in vitamin C tablets and fruits are further achieved, which are in good agreement with those of commercial colorimetric test kits. This study helps guide the rational preparation of versatile and highly stable nanozymes, and develops a robust TAC determination platform for future food quality monitoring.

Biomass‐Derived Porous Carbon as an Enzyme Mimic for Colorimetric Detection of Ascorbic Acid

AbstractPowder porous carbon (PPC) has been fabricated by using corncob, a by‐product of corn production, through a simple calcination process. The relevant carbon material retains an intrinsic porous structure and has a large specific surface area of 577.15 m2/g. The oxidase‐like and peroxidase‐like activities of porous carbon based on corncob are explored in the pH range of 2.0‐8.0, and temperature between 15 and 60 °C, and are optimal at physiological temperature. According to fluorescence and scavenger measurements, the catalytic mechanism of porous carbon with semi‐graphitized structure is from the active species including ⋅OH radicals and ⋅O2 radicals. Taking advantages of catalytic performance, a colorimetric biosensor is designed for the determination of AA with a linear range of 8 to 90 μM and a limit of detection (LOD) of 2.65 μM (S/N=3). The result proves a sustainable and environment friendly route to establish a biosensing system with porous carbon as high‐performance peroxidase mimetic.

Single-Atom Fe Nanozyme with Enhanced Oxidase-like Activity for the Colorimetric Detection of Ascorbic Acid and Glutathione

Single-atom nanozymes (SAzymes) have drawn ever-increasing attention due to their maximum atom utilization efficiency and enhanced enzyme-like activity. Herein, a facile pyrolysis strategy is reported for the synthesis of the iron-nitrogen-carbon (Fe-N-C) SAzyme using ferrocene trapped within porous zeolitic imidazolate framework-8 (ZIF-8@Fc) as a precursor. The as-prepared Fe-N-C SAzyme exhibited exceptional oxidase-mimicking activity, catalytically oxidizing 3,3',5,5'-tetramethylbenzidine (TMB) with high affinity (Km) and fast reaction rate (Vmax). Taking advantage of this property, we designed two colorimetric sensing assays based on different interaction modes between small molecules and Fe active sites. Firstly, utilizing the reduction activity of ascorbic acid (AA) toward oxidized TMB (TMBox), a colorimetric bioassay for AA detection was established, which exhibited a good linear range of detection from 0.1 to 2 μM and a detection limit as low as 0.1 μM. Additionally, based on the inhibition of nanozyme activity by the thiols of glutathione (GSH), a colorimetric biosensor for GSH detection was constructed, showing a linear response over a concentration range of 1-10 μM, with a detection limit of 1.3 μM. This work provides a promising strategy for rationally designing oxidase-like SAzymes and broadening their application in biosensing.

Preparation of the layered structure Ag@Co3O4 composites as peroxidase memetic for colorimetric detection of ascorbic acid

Co3O4 nanosheets were synthesized by precipitation method. Ag nanoparticles was successfully reduced from AgNO3 solution and loaded onto Co3O4 nanosheets to synthesize Ag@Co3O4 nanosheets. Ag@Co3O4 layered composites had obvious peroxidase-like characteristics. In the presence of hydrogen peroxide, Ag@Co3O4 layered composites could oxidize 3,3′,5,5′-tetramethylbenzidine (TMB, colorless) to oxidize TMB (ox-TMB, blue). Ascorbic acid (AA) selectively inhibited the peroxidase-like activity of Ag@Co3O4 layered composites, reducing ox-TMB (blue) to TMB (colorless). With the increase of AA concentration, a large amount of ox-TMB was reduced to TMB and the solution faded from blue gradually. Correspondingly, the increase of AA concentration directly led to the gradual decrease of the absorbance of the reaction solution at 652 nm. The Ag@Co3O4 colorimetric detection platform with a detection limit of 0.59 μM and a linear range of 2–60 μM was rapid, sensitive and selective.

Expression of concern: Novel scandium-MOF nanocrystals as peroxidase-mimicking nanozymes for highly sensitive colorimetric detection of ascorbic acid in human serum

Expression of concern for ‘Novel scandium-MOF nanocrystals as peroxidase-mimicking nanozymes for highly sensitive colorimetric detection of ascorbic acid in human serum’ by Yiqian Su et al., CrystEngComm, 2023, DOI: https://doi.org/10.1039/d2ce01023b.

Novel scandium-MOF nanocrystals as peroxidase-mimicking nanozymes for highly sensitive colorimetric detection of ascorbic acid in human serum

Novel scandium-MOF nanocrystals as peroxidase-mimicking nanozymes for highly sensitive colorimetric detection of ascorbic acid in human serum.

CeO2-Co3O4 nanocomposite with oxidase-like activity for colorimetric detection of ascorbic acid.

A CeO2-Co3O4 nanocomposite (NC) was prepared and characterized by scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction. The obtained CeO2-Co3O4 NC displayed biomimicking oxidase-like activity, which can catalytically oxidize the 3, 3', 5, 5'-tetramethylbenzidine (TMB) substrate from colorless to the blue oxidized TMB (ox-TMB) product with a characteristic absorption peak at 652 nm. When ascorbic acid (AA) was present, ox-TMB would be reduced, resulting in a lighter blue and lower absorbance. On the basis of these facts, a simple colorimetric method for detection of AA was established with a linear relationship ranging from 1.0 to 500 μM and a detection limit of 0.25 μM. When this method was used to detect AA in human serum and commercially available vitamin C tablet samples, a good recovery of 92.0% to 109.0% was obtained. Besides, the catalytic oxidation mechanism was investigated, and the possible catalytic mechanism of CeO2-Co3O4 NC can be described as follows. TMB is adsorbed on the CeO2-Co3O4 NC surface and provides lone-pair electrons to the CeO2-Co3O4 NC, leading to an increase in electron density of the CeO2-Co3O4 NC. An increased electron density can improve the electron transfer rate between TMB and the oxygen absorbed on its surface to generate O2˙- and ˙O2, which further oxidize TMB.

Self-enhanced peroxidase-like activity in a wide pH range enabled by heterostructured Au/MOF nanozymes for multiple ascorbic acid-related bioenzyme analyses.

Nanozymes, a class of catalytic nanomaterials, have shown great potential to substitute natural enzymes in various applications. Nevertheless, the pursuit of high-efficiency peroxidase-like activity in a wide pH range is one of the major challenges existing in designing nanozymes. A feasible strategy is to construct an artificial active center by using porous materials as stable supporting structures, which can actively modulate biocatalytic activities via their porous atomic structures and more active sites. Herein, a gold nanoparticles/metal-organic framework (MOF) heterostructure was prepared using UiO-66 as a stable support structure (Au NPs/UiO-66), which demonstrates enhanced peroxidase-like activity, ∼8.95 times higher than that of pure Au NPs. Strikingly, Au NPs/UiO-66 exhibits excellent stability (maintains above 80% activity at 40-70 °C and retains 93% activity after 3 months of storage) and sustained high relative activity (above 90%) over a pH range of 5.0-9.0 due to the homogeneous dispersibility of free-ligand Au NPs and the strong chemical interaction between the Au NPs and the UiO-66 host. Moreover, a colorimetric assay of ascorbic acid (AA) and three AA-related biological enzymes was developed based on Au NPs/UiO-66 nanozyme, which has a good linear detection range and excellent anti-interference ability. This work provides important guidance for the expansion of metal NPs/MOF heterostructure nanozymes and their application prospects in the development of biosensors.

Investigating the oxidase-like activity of a Co–Fe Prussian blue analogue nanocube prepared in situ and its applications in the colorimetric detection of ascorbic acid, alkaline phosphatase, α-glucosidase, and ascorbic acid oxidase

A Co–Fe Prussian blue analogue nanocube (Co–Fe PBA NC) was prepared in situ. Based on the excellent oxidase-like activity of Co–Fe PBA NC, a colorimetric sensor is developed for the detection of ascorbic acid-related bioenzymes.

Synthesis and characterization of clay graphene oxide iron oxide (clay/GO/Fe2O3)-nanocomposite for adsorptive removal of methylene blue dye from wastewater

Multifunctional clay graphene oxide iron oxide nanocomposite was prepared for exploring the multiple applications by using single composite. Activated MM clay (local clay “Multani Matti”) and graphene oxide (16 and 5%) were mixed gradually to already prepared Fe2O3 nanoparticles followed by annealing at 550 °C to get the fine structured nanocomposite. Clay graphene oxide iron oxide nanocomposite structure was revealed to be face centered cubic with the average particle size of 13.31 nm. The JCPDS data card # (00–013-0458), (00–039-1894) and (00–001-0646) were used to confirm the XRD peaks of synthesized nanocomposite. The prepared nanocomposite showed colorimetric detection of ascorbic acid using paper sensor when treated with uric acid and ascorbic acid respectively. Antibacterial results confirmed the biologically active nature of synthesized material. The photo-luminescence peaks at higher absorption range correlate the minimum efficiency of photocatalytic application than that of adsorption. The adsorption and photocatalytic degradation of organic dyes are main perspectives observed for synthesized Clay/GO/Fe2O3 nanomaterial. BET result shows a higher surface area confirming the capability of Clay/GO/Fe2O3 nanomaterial an improved adsorbent material for removal of toxic dyes even in lower concentration. The nanocomposite showed capability of all the parameters of adsorption studies in terms of effect of contact time, initial dye concentration, adsorbent dosage, pH and temperature by removing methylene blue (MB). Results showed that adsorption of MB followed second order kinetic model. The improved performance of the nanocomposite compared to single phase materials proved to be an appealing contender being used as an efficient adsorbent which could replace conventional and multiple methods for treatment of waste waters as well.

Facile Synthesis of Magnetic Iron-Based Nanoparticles from the Leach Solution of Hyperaccumulator Plant Pinus brutia for the Antibacterial Activity and Colorimetric Detection of Ascorbic Acid.

It has been well known that metallic nanoparticles with striking properties possess wide application prospects in the processes of colorimetric detection, catalysis, disease diagnosis and treatment, energy, wastewater treatment, remediation, and antibacterial activity in recent years. Herein, iron-based nanoparticles (FeNPs), metallic nanoparticles, were synthesized via a facile chemical reduction method using a hyperaccumulator plant. Also, their use in antibacterial activity applications and colorimetric ascorbic acid (AA) detection was investigated. It was observed that FeNPs presented high antibacterial potency against Gram-positive bacteria of Listeria monocytogenes and Staphylococcus aureus and also Gram-negative bacteria of Escherichia coli(O157: H7), E. coli(ATCC 25922), Salmonella enteritidis, and Salmonella typhimurium. Moreover, it was found that FeNPs exhibited superior peroxidase-like activity to catalyze the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB) to produce a blue color product, oxidized TMB (oxTMB), in the presence of H2O2. The colorimetric AA detection could be carried out by making the solution color lighter owing to the antioxidant property of AA. The quantitative detection of AA could be performed simply, selectively, and sensitively with FeNPs with a detection limit (LOD) of 0.5462 μM in a linear range of 30-200 μM.