Shozi Kawase

Analysis of wool fiber by alkali-catalyzed pyrolysis gas chromatography

Alkali-catalyzed pyrolysis gas chromatography (PyGC) has been used to identify minute samples of wool fiber. The wool sample to which aqueous sodium hydroxide was added was pyrolyzed in a Curie-point pyrolyzer attached to a gas chromatograph or a gas chromatograph-mass spectrometer. The addition of an aqueous solution of sodium hydroxide increased the production of specific volatile pyrolysis products from the constitutive amino acid residues of wool protein, i.e. acetaldehyde from alanine or proline, isobutyronitrile from valine, 2-methylbutyronitrile from isoleucine, isovaleronitrile from leucine and toluene from phenylalanine. Compared with conventional non-catalyzed PyGC, the alkali-catalyzed PyGC was found to greatly improve the detection limit of wool fiber and make it possible to analyze very minute samples. The alkali-catalyzed PyGC presented here has been shown to be applicable to minute thermally-denatured samples of wool fiber which cannot be identified successfully by morphological inspection using a microscope or by using Fourier-transform infrared microspectroscopy. Furthermore, the present PyGC method was successfully used for several protein samples and was shown to be useful for analysis of proteins other than wool fibers by using different special pyrograms reflecting different amino acid compositions.

Rapid Analysis by Capillary Gas Chromatography of Thinners and the Related Organic Solvents.

The inhalation of thinners and the related organic solvents (e.g., toluene, methanol, ethyl acetate etc.) expected as an anesthetic and stimulus, is still a social problem in connection with juvenile delinquency. For the purpose of a rapid identification of the abused solvents, 38 pure organic solvents and 18 commercial thinner samples were analyzed by a flame ionization detector (FID)-gas chromatograph with a DBTM-1, SUPELCOWAXTM 10 or DBTM-17 capillary column, respectively. In the cases of the DBTM-1 and SUPELCOWAXTM 10 columns, most organic solvents were successfully separated from each other under the gas chromatographic conditions as follows, a 30 m×0.53 mm i.d. thick-film (1.5 μm and 1.0 μm) fused-silica capillary column was used, and the column temperature was kept at 60°C for 1 min and then raised to 120°C and 150°C at 5°C/min. The total analysis times were 13 and 19 min. Especially, the DBTM-1 column was suitable for the forensic analysis of thinners, because methanol, ethylacetate and toluene prohibited by the law were succesfully separated from others. The column was also appropriate to identify lacquer thinner and industrial toluene. This method is more efficient, and less time-consuming than the other methods so far reported.