Heparin-stabilized gold nanoparticles-based CUPRAC colorimetric sensor for antioxidant capacity measurement
TALANTA, vol.187, pp.148-155, 2018 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 187
- Publication Date: 2018
- Doi Number: 10.1016/j.talanta.2018.05.021
- Journal Name: TALANTA
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
- Page Numbers: pp.148-155
- Keywords: Gold nanoparticles, Heparin, CUPRAC assay, Antioxidant capacity, Colorimetric sensor, OXIDATIVE STRESS, PHOTOCHEMICAL-SYNTHESIS, SILVER NANOPARTICLES, PHENOLIC-COMPOUNDS, ASSAY, CHEMISTRY
- Istanbul University Affiliated: Yes
Abstract
Sensing of total antioxidant capacity (TAC) as an integrated parameter showing the collective action of various antioxidants is an important challenge in food, biochemical and drug analysis. A novel heparin-stabilized gold nanoparticles (AuNPs)-based 'cupric reducing antioxidant capacity' (CUPRAC) colorimetric sensor was designed for TAC measurement. Heparin, a sulfated polysaccharide, was both the reducing and stabilizing agent for distinct negatively-charged AuNPs synthesis. The stabilized AuNPs were added to the copper(I)-neocuproine (Cu (I)-Nc) solution formed from the reaction of Cu(II)-Nc with antioxidants, and the absorbance of the resulting Cu (I)-Nc-AuNPs (Cu(I)-Nc cationic chelate electrostatically adsorbed on gold nanoparticles) was measured at 455 nm. As opposed to other similar AuNPs-based sensors, the proposed nano-sensor exhibited excellent (1000-fold) tolerance toward inert electrolytes without aggregation. The linear range was wider than that of conventional CUPRAC, with lower LOD (0.2 mu M for trolox) and higher molar absorptivity (8.36 x 10(4 )M(-1) cm(-1) for quercetin). The 'trolox equivalent antioxidant capacity' (TEAC) values and activity order for a number of antioxidants were in accordance with those of the reference CUPRAC assay. Antioxidant additions to black tea extract gave recoveries of 93-97% and RSD 2-6%. This green sensor significantly reduced reagent consumption, and operated in complex food samples with a simple, reliable and robust methodology.