裂解气相色谱-质谱法鉴别双组分丙烯酸汽车清漆

Discrimination of Automobile Acrylic Clear Coatings by Pyrolysis-GC/MS

  • 摘要: 为了提高微量物证鉴定中对双组分丙烯酸汽车清漆的鉴别能力,采用裂解气相色谱-质谱法(Py-GC/MS)检测该类清漆,并考察该方法在鉴定实践中的适用性。该方法的重现性好,丙烯酸聚氨酯清漆3个裂解单体的相对峰面积的日内RSD不大于5.3%,日间RSD不大于10.6%。应用该方法对6种丙烯酸氨基树脂汽车清漆样品及一例微量物证案件送检样品进行检测,结果表明,裂解气相色谱-质谱法对双组分丙烯酸汽车清漆的鉴别能力优于红外光谱法。在微量物证鉴定实践中,需要根据检材量酌情使用此方法,并注意“先无损后有损”的检验顺序。

     

    Abstract: In order to improve the discrimination of automobile acrylic clear coatings in trace evidence examination, a method of pyrolysis-gas chromatography-mass spectrometry (Py-GC/MS) was established to analyze automobile acrylic clear coatings (i.e. acrylic melamine and acrylic urethane paints), and its applicability in forensic practice was investigated. The repeatability of the method was acceptable. The RSDs of the relative peak area of the three monomers of acrylic urethane paint were no more than 5.3% in one day, or 10.6% in six days. The results show that Py-GC/MS performes better than infrared spectroscopy in discriminating acrylic clear coatings. In the forensic practice of trace evidence, the application of Py-GC/MS depends on the amount of paint sample available, and non-destructive methods should be used before destructive ones.

     

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