A new method for fast chitin extraction from shells of crab, crayfish and shrimp.

A new method for quick chitin isolation from the shells of crab, crayfish and shrimp is described. The main difference between the new method and the conventional method is two sodium hypochlorite (NaClO) treatments for 10 min each before the processes of demineralisation and deproteinisation. After the NaClO treatment, only 15 min is adequate for the demineralisation and 20 min for the deproteinisation processes. Newly extracted chitin from crab, crayfish and shrimp shells and commercial chitin were characterised using FT-IR, TGA, X-ray diffractometry and elemental analysis. From the results, it was observed that the chitins isolated with the new method and the commercial chitin had almost the same physicochemical properties. The advantage of the new method compared to traditional methods is the relatively rapid chitin extraction. When compared to the traditional chitin extraction method, the proposed method appears to be promising regarding its time and energy saving nature.

The quick extraction of chitin from an epizoic crustacean species (Chelonibia patula).

Chitin was isolated from the shells of Chelonibia patula (barnacle, Crustacea), which lives on blue crab epizoically, following a 10-min demineralisation process through HCl and a 20-min deproteinisation process through NaOH. Due to the low-crystalline structure, and mineral-rich and low-protein content of the shells, chitin isolation was convenient. It was observed that the shell structure of C. patula contains 3.11% chitin per its dry weight. Following characterisation of the isolated chitin by using Fourier transform infrared spectroscopy, thermogravimetric analysis, X-ray diffractometry, elemental analysis and scanning electron microscopy, it was determined that there was close similarity with the α-chitin isolated from crabs, shrimps and insects in various studies. It was observed that chitin was composed of nanofibres with a width of 10-20 nm. It was concluded that this was an economically advantageous chitin resource compared with crustaceans such as shrimp, crayfish and crab, because it is possible to isolate chitin in a significantly shorter time.

Subtractive-FTIR spectroscopy to characterize organic matter in lignite samples from different depths.

Organic matter present in lignite samples collected from different depths (i.e. top, mid and bottom) of lignite source, Ilgin, Konya province, was examined by using subtractive-FTIR-ATR spectroscopy. FTIR spectra were recorded on (i) original samples, (ii) the samples dried at 105 °C and (iii) the samples acid-treated and dried. After a combustion process performed for each sample at 650 °C for 15 min, the spectra of samples were recorded and subtracted from the spectra of untreated samples. Hence, a software-based subtraction made it possible to acquire a representative spectra related with organic matter. As the contribution of the bands related with inorganic constituents in lignite samples were eliminated after spectrum-subtraction procedure, difference-spectra led analyzing the spectra related with organic matter in lignite samples, reasonably. Furthermore, the bands related with acidic functional groups, aromatic and aliphatic structures were analyzed on the basis of difference-spectra, easily. From the difference-spectra it was shown that an acid-treatment process under mild conditions caused shift in some specific bands related with carbonyl groups of carboxyls so that the band at around 1710 cm(-1) arisen, while the intensity of the band at around 1420 cm(-1) was diminished. Through the acid-treatment process, acidic groups in lignite samples from different depths were thought to be turned into similar forms by protonation and/or stripping of metal ions originally bonded. Difference-spectra acquired for acid-treated samples made it possible to evaluate the form of carboxylic acid groups present in the studied samples under specific environmental conditions. Hence, a facile and environmentally-friendly methodology was used to analyze organic matter in lignite by using FTIR spectra, and valuable information was acquired about the aliphatic, aromatic and acidic character of the studied lignite samples collected from different depths. The proposed methodology seems to be promising in acquiring approximate representative spectra for lignite organic matter by using little or no chemicals.