Nanotechnological Methods of Antioxidant Characterization

Apak, Reşat; Çapanoğlu, Esra; Arda, Ayşem

doi:10.1021/bk-2015-1191.ch016

Cited by 4 publications

(2 citation statements)

References 108 publications

(113 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, because the approach is relatively labor intensive and time-consuming, it is ill suited for a fast and automated analysis. An alternative approach are reduction-based assays (reviewed in refs − ), which are widely used in physiology, pharmacology, food chemistry, and biogeochemistry. − These assays quantify the reduction of an added chemical oxidant by phenols in the analyzed samples. The most commonly used assay uses the radical cation of 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (i.e., ABTS •+ ) as an oxidant, because it has a high water solubility and a standard reduction potential (i.e., E h 0 (ABTS •+ /ABTS) = 0.70 V) sufficiently high to oxidize phenols.…”

Section: Introductionmentioning

confidence: 99%

Quantification of Phenolic Antioxidant Moieties in Dissolved Organic Matter by Flow-Injection Analysis with Electrochemical Detection

Walpen

Schroth

Sander

2016

Environ. Sci. Technol.

View full text Add to dashboard Cite

Phenolic moieties in dissolved organic matter (DOM) play important roles as antioxidants in oxidation processes in natural and engineered systems. This work presents an automated and highly sensitive flow injection analysis (FIA) system coupled to both spectrophotometric and electrochemical detection to quantify electron-donating phenolic moieties in DOM by determining the number of electrons that these moieties transfer to an added chemical oxidant, the radical cation of 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(•+)). The FIA system was successfully validated using Trolox as a redox standard. Highest method sensitivity was attained when combining the FIA with chronoamperometric detection, resulting in limits of quantification of picomolar amounts of Trolox and nanogram amounts of DOM (corresponding to solutions with <1 mg carbon per liter). The analysis of DOM isolates showed a strong linear correlation between the number of electrons donated and their titrated phenol contents, supporting oxidation of phenols by ABTS(•+). The broad application spectrum of the FIA system to dilute natural DOM samples was illustrated by analyzing water samples collected from northern peatlands and by monitoring the oxidation of phenols in one peat sample upon incubation with a phenol oxidase. The superior analytical capability of the FIA system allows quantifying phenols and monitoring phenol dynamics in dilute DOM samples.

show abstract

Section: Introductionmentioning

confidence: 99%

Quantification of Phenolic Antioxidant Moieties in Dissolved Organic Matter by Flow-Injection Analysis with Electrochemical Detection

Walpen

Schroth

Sander

2016

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Thus, nanoparticle-based TAC assays rely on the principle of chemical reduction of noble metal salts/acids by antioxidant polyphenols to produce noble metal NPs that can be easily identified/quantified via their localized SPR (i.e., charge density oscillations confined to metallic nanoclusters, abbreviated as LSPR) absorption. Most applications of NPs used as probes for food antioxidants are associated with the use of Au, Ag, magnetite (Fe 3 O 4 ) or titania (TiO 2 ) nanoparticles and quantum dots (QDs), in which chemical reduction-based nanotechnological colorimetric assays of antioxidant capacity make use of the formation or enlargement of noble metal nanoparticles, and antioxidants with the highest TAC values exhibited the highest ability to produce Au/Ag-NPs from Au(III)/Ag(I) salts, as recently reviewed by Apak et al [ 13 ].…”

Section: Design Strategies and Accomplishments For Colorimetric Sementioning

confidence: 99%

Novel Spectroscopic and Electrochemical Sensors and Nanoprobes for the Characterization of Food and Biological Antioxidants

Apak

Çekiç

Üzer

et al. 2018

Sensors

Self Cite

View full text Add to dashboard Cite

Since an unbalanced excess of reactive oxygen/nitrogen species (ROS/RNS) causes various diseases, determination of antioxidants that can counter oxidative stress is important in food and biological analyses. Optical/electrochemical nanosensors have attracted attention in antioxidant activity (AOA) assessment because of their increased sensitivity and selectivity. Optical sensors offer advantages such as low cost, flexibility, remote control, speed, miniaturization and on-site/in situ analysis. Electrochemical sensors using noble metal nanoparticles on modified electrodes better catalyze bioelectrochemical reactions. We summarize the design principles of colorimetric sensors and nanoprobes for food antioxidants (including electron-transfer based and ROS/RNS scavenging assays) and important milestones contributed by our laboratory. We present novel sensors and nanoprobes together with their mechanisms and analytical performances. Our colorimetric sensors for AOA measurement made use of cupric-neocuproine and ferric-phenanthroline complexes immobilized on a Nafion membrane. We recently designed an optical oxidant/antioxidant sensor using N,N-dimethyl-p-phenylene diamine (DMPD) as probe, from which ROS produced colored DMPD-quinone cationic radicals electrostatically retained on a Nafion membrane. The attenuation of initial color by antioxidants enabled indirect AOA estimation. The surface plasmon resonance absorption of silver nanoparticles as a result of enlargement of citrate-reduced seed particles by antioxidant addition enabled a linear response of AOA. We determined biothiols with Ellman reagent−derivatized gold nanoparticles.

show abstract

Methods to evaluate the scavenging activity of antioxidants toward reactive oxygen and nitrogen species (IUPAC Technical Report)

Apak

Calokerinos

Gorinstein

et al. 2021

Pure and Applied Chemistry

View full text Add to dashboard Cite

This project was aimed to identify the quenching chemistry of biologically important reactive oxygen and nitrogen species (ROS/RNS, including radicals), to show antioxidant action against reactive species through H‐atom and electron transfer reactions, and to evaluate the ROS/RNS scavenging activity of antioxidants with existing analytical methods while emphasizing the underlying chemical principles and advantages/disadvantages of these methods. In this report, we focused on the applications and impact of existing assays on potentiating future research and innovations to evolve better methods enabling a more comprehensive study of different aspects of antioxidants and to provide a vocabulary of terms related to antioxidants and scavengers for ROS/RNS. The main methods comprise the scavenging activity measurement of the hydroxyl radical (•OH), dioxide(•1–) (O2 •–: commonly known as the superoxide radical), dihydrogen dioxide (H2O2: commonly known as hydrogen peroxide), hydroxidochlorine (HOCl: commonly known as hypochlorous acid), dioxidooxidonitrate(1–) (ONOO−: commonly known as the peroxynitrite anion), and the peroxyl radical (ROO•). In spite of the diversity of methods, there is currently a great need to evaluate the scavenging activity of antioxidant compounds in vivo and in vitro. In addition, there are unsatisfactory methods frequently used, such as non-selective UV measurement of H2O2 scavenging, producing negative errors due to incomplete reaction of peroxide with flavonoids in the absence of transition metal ion catalysts. We also discussed the basic mechanisms of spectroscopic and electrochemical nanosensors for measuring ROS/RNS scavenging activity of antioxidants, together with leading trends and challenges and a wide range of applications. This project aids in the identification of reactive species and quantification of scavenging extents of antioxidants through various assays, makes the results comparable and more understandable, and brings a more rational basis to the evaluation of these assays and provides a critical evaluation of existing ROS/RNS scavenging assays to analytical, food chemical, and biomedical/clinical communities by emphasizing the need for developing more refined, rapid, simple, and low‐cost assays and thus opening the market for a wide range of analytical instruments, including reagent kits and sensors.

show abstract

Nanotechnological Methods of Antioxidant Characterization

Cited by 4 publications

References 108 publications

Quantification of Phenolic Antioxidant Moieties in Dissolved Organic Matter by Flow-Injection Analysis with Electrochemical Detection

Quantification of Phenolic Antioxidant Moieties in Dissolved Organic Matter by Flow-Injection Analysis with Electrochemical Detection

Novel Spectroscopic and Electrochemical Sensors and Nanoprobes for the Characterization of Food and Biological Antioxidants

Methods to evaluate the scavenging activity of antioxidants toward reactive oxygen and nitrogen species (IUPAC Technical Report)

Contact Info

Product

Resources

About