Fabrication of a carbon nanotube-polyurethane composite electrode by in situ polyaddition for use in amperometric detection in capillary electrophoresis

Electroanalysis of Naringin at Electroactivated Pencil Graphite Electrode for the Assessment of Polyphenolics with Intermediate Antioxidant Power

A simple and rapid differential pulse voltammetric (DPV) method using a single-use electroactivated pencil graphite electrode (PGE*) is proposed for the rapid screening of the total content of polyphenolics (TCP) with intermediate antioxidant power (AOP) in grapefruit peel and fresh juice. The results were compared and correlated with those provided by the HPLC-DAD-MS method. NG voltammetric behavior at PGE* was studied by cyclic voltammetry and an oxidation mechanism was suggested. The experimental conditions (type of PGE, electroactivation procedure, pH, nature and concentration of supporting electrolyte) for NG DPV determination were optimized. The NG peak current varied linearly with the concentration in the ranges 1.40 × 10^-6-2.00 × 10^-5 and 2.00 × 10^-5-1.40 × 10^-4 mol/L NG and a limit of detection (LoD) of 6.02 × 10^-7 mol/L NG was attained. The method repeatability expressed as relative standard deviation was 7.62% for the concentration level of 2.00 × 10^-6 mol/L NG. After accumulation for 240 s of NG at PGE* the LoD was lowered to 1.35 × 10^-7 mol/L NG, the linear range being 6.00 × 10^-7-8.00 × 10^-6 mol/L NG. The developed electrochemical system was successfully tested on real samples and proved to be a cost-effective tool for the simple estimation of the TCP with intermediate AOP in citrus fruits.

Measurement of Naringin from Citrus Fruits by High-Performance Liquid Chromatography - a Review

Naringin is a flavonoid found primarily in citrus species with especially high concentrations being present in grapefruit (Citrus paradisi), bitter orange (Citrus aurantium), and pomelo (Citrus grandis). Because of its many positive effects on human health, naringin has been the focus of increasing attention in recent years. Recently, conventional extraction methods have been commonly replaced with unconventional methods, such as ultrasound-assisted extraction (UAE) and other, more eco-friendly extraction methods requiring little-to-no environmentally harmful solvents or significantly less energy. Naringin analysis is most commonly done via high-performance liquid chromatography (HPLC), and ultrahigh-performance liquid chromatography (UHPLC) coupled with a mass spectrometer (MS) or a photodiode array (DAD) detector. The aim of this review is to provide an overview of recent trends developments in the extraction, sample preparation, and liquid chromatographic analysis of the compound originating from citrus fruits or their products.

Design and development of IDE sensor for naringin quantification in pomelo juice: An indicator of citrus maturity

Maturity determination of pomelo fruits having health-benefiting attributes is an important issue to enhance the quality of harvesting. Here, an interdigitated electrode (IDE) based sensor is introduced to detect its maturity by determining the naringin content. The sensor was made by depositing amberlite IRA-400 as a sensing layer on IDE patterned PCB substrate at room temperature with hydrothermal and spin-coating techniques. The sensor exhibits excellent selectivity for naringin, high sensitivity of 0.008 µA for 10 ppb of naringin, and reusability up to 3-4 times for naringin quantification in maturity testing of fruits. The pomelo fruits start to mature when maximum values of current response and naringin content are found at 140 DAFS. The naringin content decreases as maturity progresses and maximum phytochemical attributes were obtained at 180-220 DAFS. The IDE sensor assures an appropriate period of plucking of pomelo fruits improving harvesting practices and trade of citrus fruits.