Determination of degree of deacetylation of chitosan by 1H NMR spectroscopy

Hirai, Asako; Odani, Hisashi; Nakajima, Akira

doi:10.1007/bf00299352

Cited by 658 publications

(414 citation statements)

References 6 publications

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“…The determination of NMR GD is recommended for samples with high chitosan deacetylation degree and has been the method most used in these cases [23][24][25]. …”

Section: Nuclear Magnetic Resonance Of Hydrogen (1h -Nmr)mentioning

confidence: 99%

Structure and Properties of Nanocrystalline Chitosan

Pighinelli

et al. 2016

JABB

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Chitosan and its derivatives are polymers with excellent properties to be used in regenerative medicine because they guarantee efficiency in the healing process. This polymer has a great potential for the development of a new generation of biomaterials that can be used in regenerative medicine and tissue engineering. The nanocrystalline chitosan (nCh) is a modified form of chitosan prepared by the method of obtaining chitosan salts. It is characterized by having the same special properties of the precursor chitosan as biocompatibility, bioactivity, be non-toxic and biodegradable. The aim of this study was to develop a new method of obtaining nanocrystalline chitosan according to their chemical and physical characterization. The material was characterized by Absorption Spectroscopy in the Infrared Region -with the Fourier transform (FTIR-ATR), scanning electron microscopy, SEM, Nuclear Magnetic Resonance, NMR, Diffraction of X-rays, particle size analysis and the potential Zeta. The results indicated that the process of obtaining nanocrystalline chitosan did not change the structure of the precursor chitosan. The analysis in the FTIR showed the same functional groups of the precursor chitosan. The 1H-NMR spectroscopy was helpful in the analysis of the chitosan samples in a wide range of values to determine the degree of deacetylation (GD). The morphology indicates the homogeneity of the structure and the surface. The X-ray diffraction shows the reduction of crystallinity of QNC, which corresponds to the amorphous structure thereof. The value of the zeta potential of the chitosan acetate (AQ) in acid media (pH 4.43) was 43.6 mV, while the value of QNC (pH 7.3) was 15.4 mV due to its high polydispersity. The variation in particle size of samples and AQ using QNC 0.450 uM mesh filter, indicated the average particle size of 55.52 and 266.0 nm, respectively.

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“…The determination of NMR GD is recommended for samples with high chitosan deacetylation degree and has been the method most used in these cases [23][24][25]. …”

Section: Nuclear Magnetic Resonance Of Hydrogen (1h -Nmr)mentioning

confidence: 99%

Structure and Properties of Nanocrystalline Chitosan

Pighinelli

et al. 2016

JABB

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“…Determinou-se o grau de acetilação (GA) da quitosana através do espectro de ressonância magnética nuclear de próton 15 …”

Section: Quitosanaunclassified

Obtenção e caracterização de blendas colágeno-quitosana

Tonhi¹,

Plepis²

2002

Quím. Nova

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Recebido em 15/8/01; aceito em 19/2/02 PREPARATION AND CHARACTERIZATION OF COLLAGEN-CHITOSAN BLENDS. Biodegradable polymer blends were obtained using collagen and chitosan. Membranes of collagen and chitosan in different proportions (3:1, 1:1 and 1:3) were prepared by mixing their acetate solutions (pH 3.5) at room temperature. The blends were characterized by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier Transform infrared (FTIR) spectroscopy, specific viscosity, water absorption and stress-strain assays. The results showed that chitosan did not interfere in the structural arrangement of the collagen triple helix and the properties of the blends can be controlled by varing the proportion of the collagen and the chitosan.Keywords: blends; collagen; chitosan. INTRODUÇÃOO colágeno é uma proteína fibrosa presente na pele, tendões, ossos, dentes, vasos sangüíneos, intestinos e cartilagens, correspondendo a 30% da proteína total e a 6% em peso do corpo humano.A quitosana é um copolímero constituído de b-(1-4)-2-amino-2-deoxi-D-glicopiranose e b-(1-4)-2-acetamida-2-deoxi-D-glicopiranose, proveniente da reação de desacetilação da quitina, o segundo polissacarídeo mais abundante na natureza.O colágeno e a quitosana têm sido bastante utilizados na medicina, odontologia e farmacologia como biomateriais, pois são polímeros biocompatíveis, atóxicos e biodegradáveis, além de possuírem inú-meras propriedades biológicas [1][2][3][4][5][6] . As blendas poliméricas constituem-se na mistura de pelo menos dois polímeros ou copolímeros sem que haja qualquer reação quími-ca entre eles 7 . O interesse nesta área deve-se às crescentes aplicações práticas destes novos materiais e os principais estudos são voltados para a melhoria de suas propriedades físicas, físico-químicas e de processamento destes materiais, comparadas às propriedades dos polímeros puros 8 . Muitas blendas formadas pela combinação de biopolímeros, têm grande importância na área de biomateriais, sendo que é possível juntar as propriedades individuais de cada material em um só, além da possibilidade de melhorar ou controlar as suas propriedades mecânicas e biológicas através da interação entre as suas estruturas quí-micas diferentes. Recentemente, membranas e hidrogéis provenientes da mistura de colágeno e quitosana foram investigados pelas suas aplicações potenciais no campo dos biomateriais 9,10 . Já foi demostrado que as interações entre o colágeno e a quitosana dependem da organização estrutural do colágeno e da quantidade e distribuição de cargas ao longo das cadeias dos dois polímeros 11 . Estas propriedades estão diretamente relacionadas com o pH do meio, que é uma propriedade de fundamental importância para o estudo da interação entre eles em solução.Este trabalho teve por objetivos obter blendas colágeno-quitosana em diferentes proporções (3:1, 1:1 e 1:3) em pH 3,5, estudar a interação entre estes dois biopolímeros tanto na forma de membranas como em solução e avaliar suas propriedades físico-químicas. PARTE EXPERIMENTAL C...

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“…Both chitin and chitosan are β (1-4) glycans formed by 2-acetamide-2-deoxy-D-glucopyranose and 2-amino-2-deoxy-D-glucopyranose units (as shown in Figure 1), with (C 6 H 10 O 4 N) n as general chemical formula for this class of biopolymers [47,48]. The ratio between the two monomeric units corresponds to the N-Deacetylation Degree (or %DD in the following), which is an indication of the molar fraction of the 2-amino-2-deoxy-D-glucopyranose units (i.e., the amount of freely-available amino groups) in the biopolymer [49].…”

Section: The Chitin Industry Case Studymentioning

confidence: 99%

Aquatic-Derived Biomaterials for a Sustainable Future: A European Opportunity

Nisticò

2017

Resources

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Abstract:The valorization of aquatic-derived biowastes as possible feedstock for the production of value-added chemicals and materials is proposed here as a sustainable alternative compared to the exploitation of the more conventional (fossil) resources. In this context, the comprehension of the opportunity related to the valorization of the shellfish industry biowaste for the production of useful materials, especially focusing on chitin and its derived byproducts, is investigated. The large amount of waste produced each year by the shellfish processing industry seems to be an appealing opportunity for the European market to produce valuable products from underutilized waste. In order to highlight this important market-opportunity, the actual European situation concerning the shellfish volume of production is presented. The industrial processes necessary for the recovery of chitin, chitosan, and their derivatives are largely described, together with a wide description of their peculiar (and interesting) physicochemical properties. Even if nowadays the scientific literature suggests that this class of biopolymers is very appealing, further research is still necessary for overcoming some criticisms still present in the extraction and valorization of such substrates. However, the principles of both circular economy and green chemistry encourage the reduction of such biowastes and their exploitation as an alternative resource for a global sustainable future.

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Determination of degree of deacetylation of chitosan by 1H NMR spectroscopy

Cited by 658 publications

References 6 publications

Structure and Properties of Nanocrystalline Chitosan

Structure and Properties of Nanocrystalline Chitosan

Obtenção e caracterização de blendas colágeno-quitosana

Aquatic-Derived Biomaterials for a Sustainable Future: A European Opportunity

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