超臨界流體萃取配合高效液相層析在子彈發射火藥鑑析上之研究

• Main Authors: Yang , Tzung-han, 楊宗翰
• Other Authors: Meng , Hsien-hui
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/2z789v

碩士 === 中央警察大學 === 鑑識科學研究所 === 89 === Since the advent of leadless ammunition, the analysis of organic constituents of gunshot residues (GSR) has been regarded as complementary method and additional confirmation for inorganic analysis of GSR. Common procedures employed for organic GSR analysis are liquid extraction of samples followed by chromatographic analyses. Because thin-layer chromatographic results are not confirmative, while gas chromatography is not suitable for the analysis of thermally instable explosives, high-performance liquid chromatography with photo diode array detector were employed in this work. Supercritical fluid extraction (SFE) instead of liquid extraction was used for sample preparation to avoid the use of toxic solvent dichloromethane. Eleven standards of organic compounds that are most frequently detected in smokeless powders were firstly analyzed to optimize chromatographic operational conditions and acquire detection and quantitation limits of each compound. Calibration curve of each compound was also calculated. The extraction conditions of SFE were then optimized and the efficiency of SFE was compared to that of liquid extraction. Sixteen pre-fired and five post-fired propellant powder samples from a variety of sources were analyzed to obtain compositional information of each sample. The results were used for discrimination of samples from different sources and confirmation of samples from same sources. Analysis results of pre- and post-fired samples from same sources were also compared. Quantity ratios of compounds detected in the same sample were employed to discriminate samples from different sources. A t test was used to establish the significance of difference between the averages of quantity ratios of compared sample pairs. For pre-fired samples, when the confidence level of 99% (α=0.01) was chosen for the test, the success rate of the differentiation of samples from different sources were 93.0%. The success rate were 96.5﹪while the confidence level were 95% (α=0.05). The success rate of confirmation of samples from same sources were 80﹪regardless α=0.01 or α=0.05. During the comparison of pre- and post-fired samples, most of the samples from the same sources were differentiated as being from different sources. The possible explanation of this phenomenon is that variations of powder morphology and ingredient distribution within propellant particle resulted in varied consuming rates of different constituents during combustion, and further resulted in quantitative compositional change of post-fired powders. This result indicated that using organic analysis results to postulate the original quantitative organic composition of fired propellant powders is impractical. However, it is worthwhile to further study the potential of organic GSR analysis in the confirmation of GSR from targets and spent cases being from the same sources or not.