title: Measurement of Antioxidant Capacity by Electron Spin Resonance Spectroscopy Based on Copper(II) Reduction.
abstract: A new method is proposed for measuring the antioxidant capacity by electron spin resonance spectroscopy based on the loss of electron spin resonance signal after Cu(2+) is reduced to Cu(+) with antioxidant. Cu(+) was removed by precipitation in the presence of SCN(-). The remaining Cu(2+) was coordinated with diethyldithiocarbamate, extracted into n-butanol and determined by electron spin resonance spectrometry. Eight standards widely used in antioxidant capacity determination, including Trolox, ascorbic acid, ferulic acid, rutin, caffeic acid, quercetin, chlorogenic acid, and gallic acid were investigated. The standard curves for determining the eight standards were plotted, and results showed that the linear regression correlation coefficients were all high enough (r > 0.99). Trolox equivalent antioxidant capacity values for the antioxidant standards were calculated, and a good correlation (r > 0.94) between the values obtained by the present method and cupric reducing antioxidant capacity method was observed. The present method was applied to the analysis of real fruit samples and the evaluation of the antioxidant capacity of these fruits.
authors.affiliation: College of Chemistry, Jilin University , Qianjin Street 2699, Changchun 130012, People's Republic of China.
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.affiliation: College of Chemistry, Jilin University , Qianjin Street 2699, Changchun 130012, People's Republic of China.
authors.forename: Jia
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Department of Materials Science and Engineering, Jilin Institute of Chemical Technology , Jilin 132022, People's Republic of China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Han
authors.affiliation: Department of Materials Science and Engineering, Jilin Institute of Chemical Technology , Jilin 132022, People's Republic of China.
authors.forename: Xinyu
authors.initials: X
authors.lastname: Yu
authors.affiliation: College of Chemistry, Jilin University , Qianjin Street 2699, Changchun 130012, People's Republic of China.
authors.forename: Kun
authors.initials: K
authors.lastname: Wang
authors.affiliation: College of Chemistry, Jilin University , Qianjin Street 2699, Changchun 130012, People's Republic of China.
authors.forename: Shuang
authors.initials: S
authors.lastname: Zang
authors.affiliation: Department of Materials Science and Engineering, Jilin Institute of Chemical Technology , Jilin 132022, People's Republic of China.
authors.forename: Dayong
authors.initials: D
authors.lastname: Lu
authors.affiliation: College of Chemistry, Jilin University , Qianjin Street 2699, Changchun 130012, People's Republic of China.
authors.forename: Aimin
authors.initials: A
authors.lastname: Yu
authors.affiliation: College of Chemistry, Jilin University , Qianjin Street 2699, Changchun 130012, People's Republic of China.
authors.forename: Ziwei
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D001205:Ascorbic Acid / Q000032:analysis; D002109:Caffeic Acids / Q000032:analysis; D002726:Chlorogenic Acid / Q000032:analysis; D002839:Chromans / Q000032:analysis; D003300:Copper / Q000737:chemistry*; D003373:Coumaric Acids / Q000032:analysis; D004578:Electron Spin Resonance Spectroscopy; D000067030:Fruit and Vegetable Juices / Q000032:analysis; D005707:Gallic Acid / Q000032:analysis; D016014:Linear Models; D010084:Oxidation-Reduction; D011794:Quercetin / Q000032:analysis; D012431:Rutin / Q000032:analysis; D013861:Thiocyanates / Q000737:chemistry; D013997:Time Factors
chemical_list: D000975:Antioxidants; D002109:Caffeic Acids; D002839:Chromans; D003373:Coumaric Acids; D013861:Thiocyanates; D002726:Chlorogenic Acid; D012431:Rutin; D005707:Gallic Acid; D003300:Copper; D011794:Quercetin; C004999:ferulic acid; D001205:Ascorbic Acid; C010643:6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid; C040048:caffeic acid