An amperometric biosensor based on poly( l -aspartic acid), nanodiamond particles, carbon nanofiber, and ascorbate oxida
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RESEARCH PAPER
An amperometric biosensor based on poly(L-aspartic acid), nanodiamond particles, carbon nanofiber, and ascorbate oxidase–modified glassy carbon electrode for the determination of L-ascorbic acid Ceren Kaçar 1 & Pınar Esra Erden 2 Received: 24 April 2020 / Revised: 23 May 2020 / Accepted: 28 May 2020 # Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract An amperometric L-ascorbic acid biosensor utilizing ascorbate oxidase (AOx) immobilized onto poly(L-aspartic acid) (P(L-Asp)) film was fabricated on carbon nanofiber (CNF) and nanodiamond particle (ND)-modified glassy carbon electrode (GCE). Effects of AOx, ND, and CNF amounts were investigated by monitoring the response currents of the biosensor at different amounts of AOx, ND, and CNF. The electropolymerization step of L-aspartic acid on CNF-ND/GCE surface was also optimized. Scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques were used to enlighten the modification steps of the biosensor. The effects of pH and applied potential were studied in detail to achieve the best analytical performance. Under optimized experimental conditions, the AOx/P(L-Asp)/ND-CNF/GCE biosensor showed a linear response to L-ascorbic acid in the range of 2.0 × 10−7–1.8 × 10−3 M with a detection limit of 1.0 × 10−7 M and sensitivity of 105.0 μAmM−1 cm−2. The novel biosensing platform showed good reproducibility and selectivity. The strong interaction between AOx and the P(L-Asp)/ND-CNF matrix was revealed by the high repeatability (3.4%) and good operational stability. The AOx/P(L-Asp)/ND-CNF/GCE biosensor was successfully applied to the determination of L-ascorbic acid in vitamin C effervescent tablet and pharmaceutical powder containing ascorbic acid with good results, which makes it a promising approach for quantification of L-ascorbic acid. Keywords Amperometric biosensor . L-Ascorbic acid . Carbon nanofiber . Poly(L-aspartic acid) . Nanodiamond
Introduction L-Ascorbic acid or vitamin C is a water-soluble vitamin found in citrus and other fruits, and in vegetables [1]. It is widely utilized as an antioxidant in some foods, pharmaceutical formulations, and cosmetics [2]. L-Ascorbic acid plays a crucial role in some biological processes such as hormone biosynthesis, collagen formation, and amino acid metabolism [3]. The excess of ascorbic acid can lead to several disorders such as gastric irritation, urinary stones, and diarrhea, whereas its
* Pınar Esra Erden [email protected] 1
Department of Chemistry, Faculty of Science, Ankara University, 06100 Ankara, Turkey
2
Department of Chemistry, Polatlı Faculty of Science and Arts, Ankara Hacı Bayram Veli University, 06900 Ankara, Turkey
deficiency can cause muscle degeneration, anemia, Parkinson’s, Alzheimer’s, infections, or poor wound healing [3, 4]. Ascorbic acid cannot be synthesized in human body and must be provided exogenously in the diet [1]. Thus, the development of rapid and reliable techniques for the quantitative determinati
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