Design strategies for water-soluble small molecular chromogenic and fluorogenic probes.

Recently, there has been growing interest in research into the role of plant-derived antioxidants in food and human health. The beneficial influence of many foodstuffs and beverages including fruits, vegetables, tea, coffee, and cacao on human health has been recently recognized to originate from their antioxidant activity. For this purpose, the most commonly methods used in vitro determination of antioxidant capacity of food constituents are reviewed and presented. Also, the general chemistry underlying the assays in the present paper was clarified. Hence, this overview provides a basis and rationale for developing standardized antioxidant capacity methods for the food, nutraceutical, and dietary supplement industries. In addition, the most important advantages and shortcomings of each method were detected and highlighted. The chemical principles of these methods are outlined and critically discussed. The chemical principles of methods of 2,2′-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS·+) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH·) radical scavenging, Fe3+–Fe2+ transformation assay, ferric reducing antioxidant power (FRAP) assay, cupric ions (Cu2+) reducing power assay (Cuprac), Folin-Ciocalteu reducing capacity (FCR assay), peroxyl radical scavenging, superoxide anion radical (O
 2
 ·−
 ) scavenging, hydrogen peroxide (H2O2) scavenging, hydroxyl radical (OH·) scavenging, singlet oxygen (1O2) quenching assay and nitric oxide radical (NO·) scavenging assay are outlined and critically discussed. Also, the general antioxidant aspects of main food components were discussed by a number of methods which are currently used for detection of antioxidant properties food components. This review consists of two main sections. The first section is devoted to main components in the foodstuffs and beverages. The second general section is some definitions of the main antioxidant methods commonly used for determination of antioxidant activity of components in the foodstuffs and beverages. In addition, there are given some chemical and kinetic basis and technical details of the used methods.

Antioxidant activity of food constituents: an overview

Fluorescent and luminescent probes for measurement of oxidative and nitrosative species in cells and tissues: progress, pitfalls, and prospects.

Methodological aspects about in vitro evaluation of antioxidant properties.

Biomedical Diagnostics. Edited by Tuan Vo-Dinh Edited by Tuan VoDinh. CRC Press 20142014. Pages 311–356. Print ISBN: 978-1-42008514-3. eBook ISBN:. Bjorn Kemper is a senior researcher at the Biomedical Technology Center of the Srirang Manohar is an associate professor of biomedical photonic imaging. This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications.

https://www.spiedigitallibrary.org/journals/journal-of-biomedical-optics/volume-9/issue-5/0000/Book-Review-Biomedical-Photonics-Handbook/10.1117/1.1776177.pdf

Biomedical Photonics Handbook

http://www.jbc.org/content/early/2002/10/04/jbc.M209130200.full.pdf

Interfering with nitric oxide measurements: 4,5-diaminofluorescein reacts with dehydroascorbic acid and ascorbic acid

Separation conditions in capillary electrophoresis with native fluorescence detection often represent a compromise in terms of the separation and detection figures of merit. As both the separation and fluorescence properties greatly depend on pH, the ability to independently optimize pH in the separation capillary and the detection region can improve many complex separations. When using a sheath flow cell, the pH at the detection zone can be adjusted independently of the electrophoresis buffer pH. Using capillary electrophoresis with 257-nm excitation and native fluorescence detection, more than an order of magnitude improvement in the limits of detection for dopamine (from 1400 to 120 nM) and epinephrine (from 850 to 60 nM) is achieved by maintaining the basic separation conditions and an acidified sheath buffer. The detection of dopamine in an individual Aplysia californica cerebral ganglion neuron is demonstrated.

Independent optimization of capillary electrophoresis separation and native fluorescence detection conditions for indolamine and catecholamine measurements.

Determination of salicylate, gentisic acid and salicyluric acid in human urine by capillary electrophoresis with laser-induced fluorescence detection.

Capillary electrophoresis (CE) enables rapid separations with high separation efficiency and compatibility with small sample volumes. Laser-induced fluorescence detection can result in extremely low limits of detection in CE. Single-channel fluorescence detection, however, furnishes little qualitative information about a species being detected, except for its CE migration time. Use of multidimensional information often enables unambiguous identification of analytes. Combination of CE with information-rich wavelength-resolved fluorescence detection is analogous with ultraviolet–visible diode-array detection and furnishes both qualitative and quantitative chemical information about target species. This review discusses recent advances in wavelength-resolved laser-induced fluorescence detection coupled with CE, with an emphasis on instrument design.

Capillary electrophoresis with wavelength-resolved laser-induced fluorescence detection.

Ultraviolet (UV) excitation for laser-induced native fluorescence (LINF) detection in capillary electrophoresis (CE) offers impressive performance figures of merit when assaying peptides containing tyrosine or tryptophan residues, catecholamines, indolamines, and a number of other classes of analytes with appreciable fluorescence when excited by UV radiation. One of the largest drawbacks of native fluorescence detection schemes in CE-LINF systems has been the expense and the complexity of the lasers required for excitation in the deep UV wavelength range of 200−300 nm. An improved “turnkey” NeCu laser operating at 248.6 nm interfaced to a sheath flow-based CE system obtains a performance similar to that of large frame frequency-doubled Ar ion lasers. The detection limits for serotonin and dopamine (27 nM and 8 μM, respectively, for ∼3-nL injection) are similar to those obtained using a frequency-doubled Ar ion laser at 257 nm (21 nM and 8 μM, respectively). An example of the detection of serotonin-related...

Xin Zhang

Papers

Interfering with nitric oxide measurements: 4,5-diaminofluorescein reacts with dehydroascorbic acid and ascorbic acid

Independent optimization of capillary electrophoresis separation and native fluorescence detection conditions for indolamine and catecholamine measurements.

Determination of salicylate, gentisic acid and salicyluric acid in human urine by capillary electrophoresis with laser-induced fluorescence detection.

Capillary electrophoresis with wavelength-resolved laser-induced fluorescence detection.

Ultraviolet native fluorescence detection in capillary electrophoresis using a metal vapor NeCu laser.