State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China; University of Chinese Academy of Sciences, Beijing 100049, China.
Forensic Sci Int. 2020 May;310:110222. doi: 10.1016/j.forsciint.2020.110222. Epub 2020 Feb 28.
Soils are crucial trace evidence that can establish or exclude the relationship between a suspect, victim, or an object at a particular scene, which could contribute to building a case. Laser-induced breakdown spectroscopy (LIBS) and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy have been demonstrated to be effective techniques for soil characterization owing to its being rapid, non-destructive, and convenient analysis with little sample preparation requirements. Therefore, the principles of LIBS and FTIR-ATR techniques for soil forensic analysis in typical soil samples were investigated and their practical feasibility was tested by applying the techniques to forensic soil samples in two criminal cases. Principal component analysis (PCA) of a typical soil sample indicated that five typical soil types were clearly distinguished by LIBS and FTIR-ATR spectra. Variations in the soil elements (i.e., Si, Mg, Al, Ca, K, O, and N) and functional groups (i.e., OH/NH, CC/CO, SiO, CO, AlOH, and NH) are crucial indicators for soil identification. The casework results demonstrated that both LIBS and FTIR-ATR show great potential for forensic soil analysis in future cases.
土壤是至关重要的微量物证,可以确定或排除嫌疑人、受害者或特定现场物体之间的关系,这有助于建立案件。激光诱导击穿光谱(LIBS)和傅里叶变换衰减全反射红外光谱(FTIR-ATR)因其具有快速、无损、方便的分析特点,仅需少量样品制备要求,已被证明是土壤特征描述的有效技术。因此,本研究调查了 LIBS 和 FTIR-ATR 技术在典型土壤样品中的土壤法医分析原理,并通过将技术应用于两个刑事案件中的法医土壤样品来测试其实际可行性。对典型土壤样品的主成分分析(PCA)表明,LIBS 和 FTIR-ATR 光谱可清晰区分五种典型土壤类型。土壤元素(即 Si、Mg、Al、Ca、K、O 和 N)和官能团(即 OH/NH、CC/CO、SiO、CO、AlOH 和 NH)的变化是土壤识别的关键指标。案例结果表明,LIBS 和 FTIR-ATR 都具有在未来案件中进行法医土壤分析的巨大潜力。