Covalent Immobilization of Amino-β-Cyclodextrins on Glassy Carbon Electrode in Aqueous Media

Abstract

In the present work, the application of the amine electrooxidation method to achieve the grafting of amino β-cyclodextrins (CDamines) on glassy carbon electrodes (GCE) in aqueous media has been investigated. The results indicate that the electrooxidation procedure of CD-amines on GCE effects their covalent immobilization without the need of additional linkers or intermediates. Cyclic voltammograms of ferricyanide proved that the immobilized CDs cover at a large extent the GCE surface. This immobilization is due to real grafting and not the result of a weak physisorption interaction. Indeed, the presence of contributions characteristic of amide groups and the absence of peaks typical of amine groups in the XPS N 1s spectra of the modified GCE, support the evidence of the covalent bonding of the CDs to the glassy carbon surface through amide bond formation. Electrochemical experiments demonstrated that ferrocenemethanol and bentazon can be encapsulated within the cavity of the CDs immobilized on GCEs via the formation of inclusion compounds. Overall, the results of the present work show that this simple amine-electrooxidation strategy is suitable to immobilize CDs on glassy carbon surfaces while maintaining their inclusion abilities and, therefore, open the door to design cheap and simple electrochemical sensors for environmental applications.

New Highly Charged Iron(III) Metal–Organic Cube Stabilized by a Bulky Amine

“…This behavior indicates that the relaxation time of compound 1 is shorter than the lifetime of the nuclear excited state (experimental measurement time, 10 –7 s). 51 Such kind of paramagnetic fast spin relaxation has also been reported for other polynuclear Fe III -HS coupled systems. 60 , 61 …”

“…The mechanisms giving place to chemical changes under X-ray irradiation in XPS are complex and have been commented in detail elsewhere. 51 In particular, in the case of the reduction of metal cations in oxides, interionic Auger decay processes appear to play an important role. 50 Among all the chemical changes reported, the degradation of quaternary nitrogen species (deprotonation) has also been reported for some organic compounds.…”

“…The main one at 531.4 eV can be associated with CO bonds in OCO groups, while the second one at 533.0 eV may correspond to C− O bonds in OCO groups. 50,51 The minor component at 535.0 eV might be ascribed to a small oxygen satellite.…”

Realizing Fast Charge Diffusion in Oriented Iron Carbodiimide Structure for High-Rate Sodium-Ion Storage Performance

“…To clarify the results of this test, the XPS peaks of Fe 2p, C 1s, and N 1s were fitted to corresponding states of each element, as shown in Figure . The XPS peaks of C 1s were fitted to four states (CO 3 2– , CO, CN, and C–C). , The peaks of CO 3 2– and CO correspond to the surface SEI film of the electrode. The CN and C–C are related to the structure of FeNCN and carbon-based substrates in O-FeNCN/S, respectively.…”

“…The XPS peaks of C 1s were fitted to four states (CO 3 2− , C O, CN, and C−C). 48,49 The peaks of CO 3 2− and CO correspond to the surface SEI film of the electrode. The CN and C−C are related to the structure of FeNCN and carbonbased substrates in O-FeNCN/S, respectively.…”