scholarly journals Selective Voltammetric Detection of Ascorbic Acid from Rosa Canina on a Modified Graphene Oxide Paste Electrode by a Manganese(II) Complex

Biosensors ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 294
Author(s):  
Sophia Karastogianni ◽  
Dimitra Diamantidou ◽  
Stella Girousi

Voltammetric techniques have been considered as an important analytical tool applied to the determination of trace concentrations of many biological molecules including ascorbic acid. In this paper, ascorbic acid was detected by square wave voltammetry, using graphene oxide paste as a working electrode, modified by a film of a manganese(II) complex compound. Various factors, such as the effect of pH, affecting the response characteristics of the modified electrode were investigated. The relationship between the peak height and ascorbic acid concentration within the modified working electrode was investigated, using the calibration graph. The equation of the calibration graph was found to be: I = 0.0550γac + 0.155 with R2 = 0.9998, where I is the SWV current and γac is the mass concentration of ascorbic acid. The LOD and LOQ of the proposed method were determined to be 1.288 μg/L and 3.903 μg/L, respectively. Several compounds, such as riboflavin, biotin, and ions, such as Fe and Cu, were tested and it seemed that they did not interfere with the analytic signal. The proposed procedure was successfully applied in the determination of ascorbic acid in Rosa canina hips.

2020 ◽  
Vol 9 (1) ◽  
pp. 760-767 ◽  
Author(s):  
Seyed Morteza Naghib ◽  
Farahnaz Behzad ◽  
Mehdi Rahmanian ◽  
Yasser Zare ◽  
Kyong Yop Rhee

AbstractFunctionalized graphene-based nanocomposites have opened new windows to address some challenges for increasing the sensitivity, accuracy and functionality of biosensors. Polyaniline (PANI) is one of the most potentially promising and technologically important conducting polymers, which brings together the electrical features of metals with intriguing properties of plastics including facile processing and controllable chemical and physical properties. PANI/graphene nanocomposites have attracted intense interest in various fields due to unique physicochemical properties including high conductivity, facile preparation and intriguing redox behavior. In this article, a functionalized graphene-grafted nanostructured PANI nanocomposite was applied for determining the ascorbic acid (AA) level. A significant current response was observed after treating the electrode surface with methacrylated graphene oxide (MeGO)/PANI nanocomposite. The amperometric responses showed a robust linear range of 8–5,000 µM and detection limit of 2 µM (N = 5). Excellent sensor selectivity was demonstrated in the presence of electroactive components interfering species, commonly found in real serum samples. This sensor is a promising candidate for rapid and selective determination of AA.


1987 ◽  
Vol 70 (3) ◽  
pp. 518-520 ◽  
Author(s):  
Oi-Wah Lau ◽  
Shiu-Fai Luk

Abstract A simple and accurate spectrophotometric method has been developed for the determination of ascorbic acid in canned fruit juices, cordials, and soft drinks, based on the reduction of iron(III) by ascorbic acid to iron(II), which is then complexed with 1,10-phenanthroline. Background correction is necessary for most samples and can be achieved by copper(II)-catalyzed oxidation of the acid. The calibration graph was linear from 0 to 8 μg/mL of ascorbic acid with a slope of 0.12/ppm. The precision for the determination of ascorbic acid in a lemon drink containing 210 μg/mL of the acid was 0.9%. Many ingredients commonly found in fruit juices, cordials, and soft drinks do not interfere; however, tannic acid, pyrogallol, and sulfite interfere with the method. A wide range of samples was analyzed for ascorbic acid content by the proposed method. The samples included mango and lemon tea drinks and also grapefruit juices, for which no background correction is needed.


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