Application of micro-TLC to the total antioxidant potential (TAP) measurement.

DPPH is commonly applied for estimation of antioxidant capacity of single and complex biological samples, and changes colour from purple to yellow during reduction to DPPH-H. Importantly, for some samples, for example coloured foods, such reaction cannot be used because of interference from pigments. Therefore, the number of reported quantitative protocols involving off- or on-line sample reaction with DPPH are based on chromatographic separation of target components.

A fast and simple method for the measurement of total antioxidant potential and a fingerprint of antioxidants.

The goal of this paper is to demonstrate a new approach to the chromatographic total antioxidant potential (TAP) assay and chromatographic fingerprints of honeys. The analyte is analyzed using reversed-phase high-performance liquid chromatography with electrochemical (amperometric) detection. The TAP measure was the total surface area of all recorded chromatographic peaks (on the amperometric detector in the oxidation potential range) on the chromatogram.

Low-parachor solvents extraction and thermostated micro-thin-layer chromatography separation for fast screening and classification of spirulina from pharmaceutical formulations and food samples.

The goal of this paper is to demonstrate the separation and detection capability of eco-friendly micro-TLC technique for the classification of spirulina and selected herbs from pharmaceutical and food products. Target compounds were extracted using relatively low-parachor liquids. A number of the spirulina samples which originated from pharmaceutical formulations and food products, were isolated using a simple one step extraction with small volume of methanol, acetone or tetrahydrofuran.

A new total antioxidant potential measurements using RP-HPLC assay with fluorescence detection.

In this paper, an improved total antioxidant potential (TAP) estimation using high-performance liquid chromatographic (HPLC) assay with fluorometric detection has been described. The principle of this method is based on the hydroxyl radicals generated in the Fenton-like reaction and subsequently detected using hydroxyterephthalic acid (HTPA), which is a reaction product of hydroxyl radicals and terephthalic acid (TPA), working as a sensing compound. HTPA quantity in the samples was measured by fluorescence detector working at excitation and emission wavelengths equal to 312 and 428 nm, respectively.

Optimization of a solid-phase extraction protocol for fractionation of selected steroids using retention data from micro thin-layer chromatography.

In this paper a simple protocol is described for estimating of solid-phase extraction (SPE) elution volumes of steroids based on retention data generated from micro-planar chromatography. Particularly, the retention of selected steroids, including estrogens and progestagens, was studied on wettable with water octadecylsilica HPTLC plates and mobile phases composed of methanol:water mixtures ranging from 20 to 100% (v/v). It was found that TLC retention data can be linearized by plotting R(M) values of steroids against a reciprocal form of the organic modifier molar fraction (1/X(s)).

Modeling of ion-exclusion and vacancy ion-exclusion chromatography in analytical and concentration overload conditions.

Ion-exclusion chromatography (IEC) finds applications in various different analytical separations of weak acids. Pure, deionized water or a diluted, aqueous solution of a strong mineral acid (such as, e.g.

A modified analytical method for total antioxidant potential assay using RP-HPLC with electrochemical detection and its application for pro- and antioxidative properties of dopamine measurement.

Total antioxidant potential (TAP) is usually measured using photometric or fluorometric assays. Preliminary results of a reversed-phase high-performance liquid chromatography--electrochemical detection assay are given. The method is based on the generation of hydroxyl radicals in a Fenton reaction and analysis of the product of their interaction with p-hydroxybenzoic acid (3,4-dihydroxybenzoic acid).