Determination of total antioxidant capacity of commercial beverage samples by capillary electrophoresis via inline reaction with 2,6-dichlorophenolindophenol.

Full Abstract

This paper demonstrates proof-of-concept for the use of electrophoretically mediated microanalysis (EMMA) as a new approach to the determination of total antioxidant capacity (TAC). EMMA is a low-volume, high-efficiency capillary electrophoretic technique that has to date been underutilized for small molecule reactions. Here, nanoliter volumes of 2,6-dichlorophenolindophenol (DCIP) reagent solution are mixed with an antioxidant-containing sample within the confines of a narrow-bore capillary tube. The mixing is accomplished by exploiting differential migration rates of the reagents when a voltage field is applied across the length of the capillary tube. The ensuing electron transfer reaction between DCIP and the antioxidant(s) is then used as a quantitative measure of the TAC of the sample. Linear calibration using either redox form of DCIP is accomplished with standard solutions of ascorbic acid. Several commercial beverage samples are analyzed, and the TAC values obtained with the reported methodology are compared to results obtained with the widely used ferric reducing antioxidant power (FRAP) spectroscopic method. For the analysis of real samples of unknown ionic strength, the method of standard additions is shown to be superior to the use of external calibration. This easily automated EMMA method may represent a useful new approach to TAC determination.

Author information

Author/s: Merola, Emily T (ET); Catherman, Adam D (AD); Yehl, Jenna B (JB); Strein, Timothy G (TG);

Affiliation: Department of Chemistry, Bucknell University, Lewisburg, Pennsylvania 17837, USA.

Grants: R15 EB003854-02 (Agency:NIBIB NIH HHS)

Journal and publication information

Publication Type: Evaluation Studies; Journal Article; Research Support, N.I.H., Extramural

Journal: Journal of agricultural and food chemistry (J Agric Food Chem), published in United States. (Language: eng)

Reference: 2009-Aug; vol 57 (issue 15) : pp 6518-23

Dates: Created 2009/09/02; Completed 2009/11/03;

PMID: 19572646, status: MEDLINE (last retrieval date: 11/3/2009, IMS Date: )

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