Search

This study developed carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) as sorbents to extract flavonoids from grapefruit peel. The impact of solution pH and desorption conditions on extraction efficiency was investigated. In addition, Fourier transforms infrared spectroscopy, thermogravimetry, UVvisible spectroscopy, and scanning electron microscopy were used to characterize the carbon nanotubes. After five cycles, the desorption percentage of flavonoids was 82.7 %. HPLC analysis indicated that naringin was the dominant flavonoid in the grapefruit extracts, followed by rutin and quercetin. Insights into the adsorption mechanism of naringin to the MWCNT-COOH were obtained using the Freundlich isotherm equation to model the results. The carbon nanotubes developed in this study offer a cost-effective and straightforward method of extracting valueadded functional ingredients from food waste, thereby improving the sustainability and economic viability of the food supply. [ABSTRACT FROM AUTHOR]

ZnO-CNTs and 1-butyl-3-methylimidazolium bromide (BMIB) ionic liquid were used as amplifiers for modification of carbon paste electrode (CPE) as simple and powerful electrochemical tool for analysis of tert-butylhydroquinone (TBHQ). The pH response on electro-oxidation signal of TBHQ was investigated as effective factor on voltammetric investigation. Under the optimized conditions, a linear dynamic rage 0.09-750 µmol L-1 was detected for determination of TBHQ at surface of CPE/BMIB/ZnO-CNTs. The CPE/BMIB/ZnO-CNTs was successfully used as electro-chemical food sensor for determination of TBHQ in food samples. [ABSTRACT FROM AUTHOR]