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dc.contributor.authorCelik, S. E.
dc.contributor.authorTOR, İzzet
dc.contributor.authorOzyurek, Mustafa
dc.contributor.authorApak, R.
dc.contributor.authorBerker, K. I.
dc.contributor.authorGuclu, Kubilay
dc.date.accessioned2021-03-06T11:56:56Z
dc.date.available2021-03-06T11:56:56Z
dc.date.issued2007
dc.identifier.citationOzyurek M., Celik S. E. , Berker K. I. , Guclu K., TOR İ., Apak R., "Sensitivity enhancement of CUPRAC and iron(III)-phenanthroline antioxidant assays by preconcentration of colored reaction products on a weakly acidic cation exchanger", REACTIVE & FUNCTIONAL POLYMERS, cilt.67, ss.1478-1486, 2007
dc.identifier.issn1381-5148
dc.identifier.otherav_f1805508-d5fe-4584-83c5-c0799abb67ca
dc.identifier.othervv_1032021
dc.identifier.urihttp://hdl.handle.net/20.500.12627/158461
dc.identifier.urihttps://doi.org/10.1016/j.reactfunctpolym.2007.07.030
dc.description.abstractThe chemical diversity of antioxidants (acting as non-enzymatic defenses of an organism to oxidative stress) makes it difficult to separate and quantify antioxidants from the vegetable matrix. We report the development of simple and widely applicable total antioxidant capacity (TAC) assays of increased sensitivity quantitating dietary polyphenols, vitamins C and E from dilute solutions utilizing the copper(II)-neocuproine (Cu(II)-Nc) and iron(III)-phenanthroline (Fe(III)-phen) reagents as chromogenic oxidants. The sensitivities of the CUPRAC (cupric ion reducing antioxidant capacity) method for TAC, and of Fe(III)-phen method for ascorbic acid assays were enhanced by preconcentration of colored species derived from the redox reaction of chromogenic oxidant with the tested antioxidant. The proposed method was useful in concentrating the colored cations derived from the antioxidant values of dilute solutions where ordinary TAC assays gave negligible absorbances. When an antioxidant reduced the chromogenic reagents Cu(II)-Nc or Fe(III)-phen, the resulting large cations of Cu(Nc)(2)(+)and Fe(phen)(2)(+) were selectively retained by a weakly acidic cation exchanger Amberlite IRC-50 resin in 2 3 Na+-form. The ferrous-phenanthro line and cuprous-neocuproine cations were retained at pH 6 and 7, respectively, on IRC-50 resin. The resin-retained species were eluted with (1: 1 (v/v) EtOH - 1 M aqueous HQ and (1:1 (v/v) EtOH + 1 M aqueous HClO4) solutions, respectively, for ferrous and cuprous species, yielding preconcentration factors between 5 and 10. The Fe(phen)(3)(2+)-containing eluate was adjusted to pH 6 and its absorbance measured at 510 nm, while the absorbance 3 of the Cu(Nc)(2)(+)-containing eluate was directly measured at 450 nm. The proposed assays were rapid, and the formed complexes were stable. Preconcentration of antioxidant solutions by the proposed 'sorption-spectrophotometry' increased analytical sensitivity. (c) 2007 Elsevier Ltd. All rights reserved.
dc.language.isoeng
dc.subjectMühendislik
dc.subjectKİMYA, UYGULAMALI
dc.subjectKimya
dc.subjectTemel Bilimler (SCI)
dc.subjectMÜHENDİSLİK, KİMYASAL
dc.subjectMühendislik, Bilişim ve Teknoloji (ENG)
dc.subjectPOLİMER BİLİMİ
dc.subjectKimya Mühendisliği ve Teknolojisi
dc.subjectFizikokimya
dc.subjectPolimer Karakterizasyonu
dc.subjectDiğer
dc.subjectTemel Bilimler
dc.subjectMühendislik ve Teknoloji
dc.titleSensitivity enhancement of CUPRAC and iron(III)-phenanthroline antioxidant assays by preconcentration of colored reaction products on a weakly acidic cation exchanger
dc.typeMakale
dc.relation.journalREACTIVE & FUNCTIONAL POLYMERS
dc.contributor.department, ,
dc.identifier.volume67
dc.identifier.issue12
dc.identifier.startpage1478
dc.identifier.endpage1486
dc.contributor.firstauthorID52982


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