A method for forensic identification of vegetable oil stains--rapid analysis of carboxylic acids with methyl esterification using purge-and-trap gas chromatography/mass spectrometry
Ehara, Y
Criminal Investigation Laboratory, Saitama Prefecture Police Headquarters, 15-1, Takasago 3-chome, Saitama-shi, Saitama 336-8533, Japan.

Ehara, Y
Department of Environmental Science and Human Engineering, Graduate School of Science and Engineering, Saitama University, 255 Simookubo,Saitama-shi, Saitama 338-0825, Japan.

Sakamoto, K
Department of Environmental Science and Human Engineering, Graduate School of Science and Engineering, Saitama University, 255 Simookubo,Saitama-shi, Saitama 338-0825, Japan.

Marumo, Y
National Research Institute of Police Science, 3-1, Kashiwanoha 6-chome, Kashiwa, Chiba 277-0881, Japan.


Abstract
A simple method using purge-and-trap gas chromatography/mass spectrometry (P&T-GC/MS) for forensic examination of oil stains was studied. Carboxylic acids, chosen as target components for discrimination of oil samples, were extracted from stains with ether, methyl esterified by tetramethylammonium hydroxide, and analyzed by P&T-GC/MS. Vegetable oils were discriminated according to their carboxylic acid compositions. Carboxylic acid composition was independent of the substrate material of the stain. Although the carboxylic acid composition of the oil changed on exposure to sunlight, identification of oil was possible for oil stains that had been in the shade, if analysis was made within 20 days.

Keywords:
carboxylic acid, exposure, forensic science, methyl esterification, oil stain, purge-and-trap gas chromatography, steroid analysis, substrate material, vegetable oil

Paper ID: JFS4661462

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Author Ehara Y, Sakamoto K, Marumo Y Title A method for forensic identification of vegetable oil stains--rapid analysis of carboxylic acids with methyl esterification using purge-and-trap gas chromatography/mass spectrometry Symposium , Committee on