Department of Chemistry and Biochemistry, University of Mississippi, University, MS 38677, USA.
Forensic Sci Int. 2013 Dec 10;233(1-3):37-44. doi: 10.1016/j.forsciint.2013.08.019. Epub 2013 Aug 30.
Students in an instrumental analysis course with a forensic emphasis were presented with a mock scenario in which soil was collected from a murder suspect's car mat, from the crime scene, from adjacent areas, and from more distant locations. Students were then asked to conduct a comparative analysis using the soil's elemental distribution fingerprints. The soil was collected from Lafayette County, Mississippi, USA and categorized as sandy loam. Eight student groups determined twenty-two elements (Li, Be, Mg, Al, K, Ca, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Rb, Sr, Cs, Ba, Pb, U) in seven samples of soil and one sample of sediment by microwave-assisted acid digestion and inductively coupled plasma-mass spectrometry (ICP-MS). Data were combined and evaluated using multivariate statistical analyses. All eight student groups correctly classified their unknown among the different locations. Students learn, however, that whereas their results suggest that the elemental fingerprinting approach can be used to distinguish soils from different land-use areas and geographic locations, applying the methodology in forensic investigations is more complicated and has potential pitfalls. Overall, the inquiry-based pedagogy enthused the students and provided learning opportunities in analytical chemistry, including sample preparation, ICP-MS, figures-of-merit, and multivariate statistics.
有犯罪学倾向的仪器分析课程的学生收到了一个模拟场景，其中从谋杀嫌疑犯的汽车垫、犯罪现场、相邻区域和更远的地方收集了土壤。然后要求学生使用土壤的元素分布指纹进行比较分析。土壤来自美国密西西比州拉斐特县，归类为沙壤土。八个学生小组通过微波辅助酸消解和电感耦合等离子体质谱法 (ICP-MS) 确定了七种土壤样本和一种沉积物样本中的二十二种元素（Li、Be、Mg、Al、K、Ca、V、Cr、Mn、Fe、Co、Ni、Cu、Zn、As、Se、Rb、Sr、Cs、Ba、Pb、U）。数据通过多元统计分析进行组合和评估。所有八个学生小组都正确地将他们的未知样本分类到不同的位置。然而，学生们了解到，虽然他们的结果表明，元素指纹识别方法可用于区分来自不同土地利用区和地理位置的土壤，但在法医调查中应用该方法更为复杂，并且存在潜在的陷阱。总的来说，基于探究的教学法激发了学生的学习兴趣，并为他们提供了分析化学方面的学习机会，包括样品制备、ICP-MS、度量指标和多元统计。
