Determination of the Degree of Acetylation of Chitin/Chitosan by Pyrolysis-Gas Chromatography in the Presence of Oxalic Acid

Abstract

A new method to determine directly and rapidly the degree of acetylation of chitin/chitosan was developed based on reactive pyrolysis-gas chromatography in the presence of an oxalic acid aqueous solution. The degree of acetylation was precisely evaluated on the basis of peak intensities of the characteristic products such as acetonitrile, acetic acid, and acetamide originating from the N-acetyl group of N-acetyl-d-glucosamine units of chitin/chitosan. The observed values were in good agreement with those obtained by (1)H NMR and the other methods. Moreover, the proposed technique was applicable to any kinds of chitin/chitosan samples over the whole range of acetylation including insoluble chitin/chitosan and perfectly acetylated artificial chitin having higher crystallinity to which (1)H NMR had been inapplicable.

Fungal chitosan production using xylose rich of corn stover prehydrolysate by Rhizopus oryzae

“…Therefore, the DD of chitosan should be determined as accurately as possible [26]. Some methods have been reported to determine the DD of chitosan, such as elemental analysis, titration, chromatography, IR and NMR spectroscopy [7,24,32]. Titration was applied to determine the DD of fugal chitosan in the paper.…”

Characterization and Properties of Chitosan

“…N-acetyl-D-glucosamine (NADG) was employed as standard to calculate the degree of acetylation (DA) of chitosan. This assumption is correct only if the characteristic products (acetonitrile, acetic acid, and acetamide) are quantitatively formed from both chitosan and NADG (Sato et al, 1998). …”

“…• Elemental analysis (Davies & Hayes, 1988;dos Santos et al, 2009); • Titration (Arcidiacono & Kaplan, 1992;Balázs & Sipos, 2007;de Alvarenga et al, 2010;Hattori et al, 1999;Park et al, 1983;Raymond et al, 1993;Tôei & Kohara, 1976;Zhanga et al, 2011); • Hydrolytic methods (Davies & Hayes, 1988;Nanjo et al, 1991;Niola et al, 1993;Sato et al, 1998;Zamani et al, 2008); • HPLC -Ultraviolet (Aiba, 1986;Muzzarelli & Rocchetti, 1985); • Infrared (Baxter et al, 1992;Duarte et al, 2002;Kasaai, 2008;Miya et al, 1980;Moore & Roberts, 1980;Sannan et al, 1978); • 1 H nuclear magnetic resonance (Brugnerotto et al, 2001;de Alvarenga et al, 2010;Fernandez-Megia et al, 2005;Lavertu et al, 2003;Varum et al, 1991); • CP-MAS 13 C NMR (Heux et al, 2000;Manni et al, 2010;Raymond et al, 1993); • CP-MAS 15 N NMR (Kasaai, 2009;Yu et al, 1999); • Many other methods are described in the literature but with a somewhat smaller appeal. Some of these methods are: steric exclusion chromatography (Brugnerotto et al, 2001), nitrous acid deamination (Sashiwa et al, 1991), thermal analysis (Garcia Alonso et al, 1983), gas chromatography with columns packed with chitin and chitosan (Muzzarelli et al, 1980),...…”

Pyrolysis-Gas Chromatography/Multiphoton Ionization/ Time-of-Flight Mass Spectrometry for the Rapid and Selective Analysis of Polycyclic Aromatic Hydrocarbons in Aerosol Particulate Matter

“…One possible system is a GC-MS that uses a pyrolyzer for the sample introduction. [28][29][30][31][32] A portable Curie-point pyrolyzer has recently become commercially available, where a sample can be safely and rapidly introduced into a GC. 33 Though the influence of an impurity is a possibility for environmental samples that have had no pretreatment, the use of a laser for MPI would successfully enhance selectivity.…”