A novel flow injection amperometric method for sensitive determination of total antioxidant capacity at cupric-neocuproine complex modified MWCNT glassy carbon electrode
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Tarih
2022
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Springer Wien
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
A novel amperometric method is presented for the determination of total antioxidant capacity in flow injection analysis (FIA) system using copper(II)-neocuproine complex modified on Nafion-functionalized multi-walled carbon nanotube-glassy carbon electrode ([Cu(Ncp)(2)(2+)]/Nf@f-MWCNT/GCE). Cyclic voltammetric studies showed that the modified electrode exhibits a very well-formed reversible redox couple for Cu(II)-/Cu(I)-complex. In addition, the [Cu(Ncp)(2)(2+)]/[Cu(Ncp)(2)(+)] redox pair shows very good electrocatalytic activity towards the oxidation of polyphenolic compounds (PPhCs) such as trolox, catechin, and quercetin due to the enhancement of the anodic peak current of the redox couple in the presence of these analytes. This electrocatalytic oxidation current at the [Cu(Ncp)(2)(2+)]/Nf@f-MWCNT/GCE was used for flow injection (FI) amperometric determination of PPhCs. FI amperometric-time curves recorded under optimized conditions (applied potential: + 0.6 V vs. Ag/AgCl/KCl(0.10 M), flow rate: 2 mL/min) showed that the proposed electrode had a wide linear range (LR) with a very low detection limit (LOD) for PPhCs. LR and LOD were 0.5-800 and 0.2 mu M for trolox, respectively and 0.50-250 and 0.14 mu M, respectively, for both quercetin and catechin. This sensitive method was successfully applied to the amperometric measurement of total antioxidant capacity (TAC) of some herbal teas, giving compatible results with the spectrophotometric CUPRAC method. The proposed method gave higher rank to fast-reacting antioxidants; it was equally precise but had a wider linear range and lower LOD than the spectrophotometric CUPRAC assay (e.g., LOD for ascorbic acid and gallic acid were 0.07 and 0.08 mu M, respectively), and similar electroanalytical methods using the CUPRAC reagent.
Açıklama
Anahtar Kelimeler
Total antioxidant capacity, Chemically modified electrode, Multi-walled carbon nanotubes, Amperometry, Flow injection analysis, Copper(II)-neocuproine complex
Kaynak
Microchimica Acta
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
189
Sayı
4
