The preparation and characterization of the hexacyanides immobilized in chitosan

Abstract

Re ceived: Oc to ber 15, 1996; Au gust 2, 1996 Mostramos neste trabalho alguns detalhes sobre a imobilização de complexos ferrocianeto e ferricianeto sobre a superfície do biopolímero quitosana. Os complexos imobilizados foram caracterizados por eletroquimica, espectrocopia de infravermelho e Mössbauer. Foi observado mudanças nos espectros de infravermelho e Mössbauer, e no voltamogramas cíclicos do ma terial preparado com ferricianeto após exposição a luz do sol. Estas alterações indicam que o ferricianeto sofreu um processo de redução fotoinduzida na superfícies do biopolímero.We re port some de tails of the ferro cyanide and ferri cyanide com plexes im mo bi lized in chitosan. These im mo bi lized com plexes are char ac ter ized by elec tro chem is try, and in fra red and Mössbauer spec tros copy. Al ter ations are ob served in the in fra red and Mössbauer spec tra and in the cy clic voltammograms of the ma te rial pre pared with ferri cyanide when this ma te ria l is ir ra di ated with sun light. These al ter ations in di cate that the ferri cyanide ion un der g oes a photoinductive re duc tion on the biopolymeric sur face. Key words: chitosan, cy clic voltammograms, photoinductive re duc tion In tro duc tionIn re cent years in creased at ten tion has been given to sun light-induced pho to chem i cal ef fects. The photoreactivity of both or ganic and in or ganic iron complexes has been rec og nized for a long time, and many reports on the ef fects of light on the chem is try of iron have been pub lished over the last 100 years 1 . In this study the prep a ra tion and char ac ter iza tion of ferro cyanide and ferricyanide com plexes im mo bi lized in chitosan is de scribed. Chitosan is a polysaccharide usu ally pre pared by the N-desacetylation of chitin, through a ba sic hy dro ly sis re action, and largely con sists of glucosamine units and a smaller per cent age of N-acetyl-glucosamine res i dues ( Fig. 1) 2 . Chitosan has a sim i lar struc ture to that of cel lu lose, but shows many prop er ties that dif fer from the lat ter, for ex ample, chitosan is con sid ered more chem i cally ver sa tile than cel lu lose, due to the pres ence of an amino group. This group gives chitosan sol u bil ity in or ganic ac ids (ace tic acid, for mic acid) and di luted in or ganic ac ids (chloridric acid). This poly mer has been the ob ject of con tin ued study for sev eral de cades. In par tic u lar, its metal-binding property has led to the use of chitosan as a low-cost ma te rial in, waste wa ter treat ment plants and streams con tam i nated by the ac cu mu la tion of toxic met als re leased by in dus trial activ i ties [3][4][5] .In a re cent re port chitosan was used in the im mo bi li zation and char ac ter iza tion of ni trite, per manga nate, io dide Ar ti cle

Chitosan: The Most Valuable Derivative of Chitin

“…Several possible explanations have been proposed for antimicrobial activity, namely, the polycationic chitosan molecule interacting with the predominantly anionic cell wall components (lipopolysaccharides and proteins) of the microorganism, which results in the leakage of intracellular components due to changes in the permeability barrier; preventing nutrients from entering the cell; upon entry into the cell (especially LMWC), binding to DNA, and thus inhibiting RNA and protein synthesis; binding through hydrophobic interactions, etc. Chitosan shows a broad-spectrum antimicrobial activity against both gram-positive and gramnegative bacteria and fungi [239].…”

The Coordination of Pyridyl-N to Pentacyanoferrate for the Electrochemical Detecting Small Organic Molecules

“…10,11 In this paper, a facile synthetic process enabling the direct coordination of pyridyl-N to pentacyanoferrate for the detection of small organic molecules is reported. 12,13 In particular, two novel strategies are employed to design the homogeneous electrochemical immunoassay system, as follows: First, the synthesized complex between pyridyl-N and pentacyanoferrate was not only an excellent electroactive molecule, but also provided direct conjugation to the antibody for the detection of the target molecules. Second, the proposed homogeneous electrochemical immunoassay is relatively simple, inexpensive and easily manipulated.…”

Electrocatalytic Oxidation of Ascorbic Acid on Carbon Paste Electrode Modified with [Ru(EDTA)(4PMC)]

“…Chemically modified electrodes (CME) have attracted a great deal attention over the past decade in a wide range of potential applications in electrochemical processes, particularly in -56 -recent reports [9] chitosan modified with 4-pyridinecarboxialhdeyde was used to prepare carbon paste modified electrode (CPME) and tested with pentacyaneferrato(II) as electroative species. The present works report the preparation, electrochemical and electron mediator properties of the polymer 4-pyridilmethylchitosan/Ru(EDTA [Ru(EDTA)(4PMC)] in MCPE .…”