Simultaneous detection and image capture of biological evidence using a combined 360° camera system with single wavelength laser illumination

Forensic investigators frequently utilise light sources to detect and presumptively identify biological evidence. The instrumentation typically deploys single or multiple wavelength exposures at various intensities, which interact with constituents of biological material, initiating fluorescence or improving contrast between the material and substrate. Documentation using sketches and/or photographic approaches follows detection, which are essential for scene reconstruction. Recent research has demonstrated the simultaneous detection and capture of biological evidence using a 360° camera system combined with an alternate light source exhibiting broad wavelength ranges of light. Single wavelength light sources reportedly offer enhanced sensitivity, due to the increased light intensity and narrower bandwidth of light, although their combined use with a 360° camera system has not yet been explored.Samples of human blood, semen, saliva, and latent fingermarks were deposited on to a variety of substrates. A 360° camera system combined with a laser light source was used to detect and capture the samples. Ten participants were asked to detect the samples on images of the substrates without ground truth knowledge. It was possible to detect and capture biological evidence, although success varied according to substrate colour and light intensity. Advantageously, presumptive screening for biological fluids and the simultaneous location and visualisation of such evidence as part of a 360° panorama of the scene for contextual purposes was permitted. There was no fluorescent response from the fingermarks, although the oblique lighting effects appeared sufficient to aid mark detection in some circumstances. The use of single wavelength illumination clearly facilitates identification of a range of forensically important material. When coupled with a 360-degree camera, this allows for simultaneous identification and recording of such evidence in the context of the whole environment.     

液相色谱-串联质谱法检测生物样品中百草枯及其代谢物

目的建立生物样品中百草枯(paraquat,PQ)及其2种主要代谢物monoquat,paraquatmonopyridone(MP)的液相色谱-串联质谱(LC-MS/MS)检测方法,应用于百草枯中毒案件的法医学鉴定。方法生物样品经乙腈或甲醇沉淀蛋白,使用Agilent HILIC Plus(4.6×100mm,3.5μm)色谱柱,以0.1%甲酸水溶液～0.1%甲酸乙腈溶液(v/v)为流动相进行洗脱,在多反应监测模式下检测。结果百草枯及其代谢物在1～1000ng/mL内线性关系良好,相关系数(r)≥0.9996,最低检出限为0.34～6.00ng/mL,检测准确度为91.25%～113.44%,日内及日间精密度分别为1.51%～3.99%和1.92%～4.93%。结论本文建立的LC-MS/MS法具有灵敏度高、特异性好的特点,可应用于百草枯中毒相关案件的法医学鉴定。