New β-Cyclodextrin Entrapped in Polyethyleneimine Film-Modified Electrodes for Pharmaceutical Compounds Determination

Abstract

Abstract:The electrochemical behavior of ascorbic acid and uric acid on glassy carbon bare electrodes and ones modified with β-cyclodextrin entrapped in polyethyleneimine film has been investigated using square wave voltammetry. The electrode modification was achieved in order to separate the voltammetric peaks of ascorbic acid and uric acid when present in the same solution. On the modified electrodes the potential of the oxidation peak of the ascorbic acid was shifted to more negative values by over 0.3 V, while in the case of uric acid, the negative potential shift was about 0.15 V compared to the bare glassy carbon electrode. When the two compounds were found together in the solution, on the bare electrode only a single broad signal was observed, while on the modified electrode the peak potentials of these two compounds were separated by 0.4 V. When the uric acid concentration remained constant, the peak intensity of the ascorbic acid is increased linearly with the concentration (r 2 = 0.996) and when the ascorbic acid concentration remains constant, the peak intensity of the uric acid increased linearly with the concentration (r 2 = 0.992). FTIR measurements supported the formation of inclusion complexes. In order to characterize the modification of the electrodes microscopic studies were performed. The modified electrodes were successfully employed for the determination of ascorbic acid in pharmaceutical formulations with a detection limit of 0.22 µM.

Surface modification of adamantane-terminated gold nanoclusters using cyclodextrins

“…These cyclodextrins (CDs) possess a cone shape that exhibits an excellent pharmacokinetic profile due to their availability at low cost with no toxicity and immunogenicity. 22,23 Their unique ability to dissolve in polar solvents and accommodate guest molecules with suitable size and geometry within their hydrophobic cavity have gained great attention over the last decade from fundamental research to technological applications, including as molecular reactors, 24 enzyme mimics, 25 electrode surface modifiers, [26][27][28] water purification, 29 and chromatographic materials. 30 Very recently, Au 38 S 2 (SAdm) 20 nanoclusters (-SAdm = adamantanethiolate) were synthesized via a ''size-focusing'' process.…”

Electrochemical Methods for Evaluation of Antioxidant Properties of Propolis Extract Incorporated in Chitosan Nanoparticles

“…UV-Vis spectra of propolis extract and nanopropolis were recorded observing peaks at 300 nm (corresponding to the aqueous propolis extract) and at 290 nm and 310 nm (for the nanopropolis sample) (Figure 8), similarly with other types of propolis from some studies [2,[26][27]. Meanwhile ascorbic acid presents absorbance at 260 nm [53]. The peaks from the UV-Vis spectra confirmed the phenolic compounds from propolis extract and nanopropolis revealed by the HPLC analysis, knowing from the literature that these compounds are visible in the range 280-350 nm [2,[26][27].…”

Exploring the Research Progress about the Applications of Cyclodextrins and Nanomaterials in Electroanalysis

“…CDs have the ability to act as molecular shape sorters, a crucial feature for the development of highly stable and sensitive sensors. Numerous applications of CDs used for the development of sensors are reported, but in very few cases it is a question of using these compounds as such, usually composite materials based on CDs or functionalized CDs being employed [25,26].…”

“…The use of conducting polymers for the functionalization of CDs was also beneficial for the electroanalytical performance, CDs being usually incorporated into polymeric films and attached to the backbone by suitable reactions, chosen according to the type of polymer, the type of CD and the degree of functionalization. The presence of the conducting polymers [15,25,26] together with CDs could offer positive or negative charged groups, as well as electrocatalytic effect toward the target molecule, thus improving the selectivity and the sensitivity of the electrochemical sensor [24,[43][44][45].…”