采用离子束切割技术进行纤维截面制样的研究

纤维为常见微量物证，高质量的纤维横截面形态能提供更多信息用于比对和生产工艺溯源，而获得清晰的横截面主要依赖于纤维截面制样技术。本文选取羊毛纤维作为研究对象建立了纤维的离子束切割方法，比较了7种固定剂对纤维包埋固化时间、样品固定情况、样品导热性和样品导电性的影响，系统考察了加速电压、切割时间、离子束摆动速度以及离子束摆动角度等关键参数对切割效果的影响，并对7种纤维依照优化后的制样方法进行截面切割。采用银浆丙酮溶液对羊毛、涤纶、空心涤纶、异形涤纶、尼龙、维纶、难燃纤维和ES纤维8种纤维进行固定，以4 V、2.5 h、3 r/min、±30°为切割条件进行切割，能获得较为满意的纤维横截面。在扫描电镜放大4 000倍的条件下能清晰观察到光滑的纤维截面形态以及孔隙内壁的结构。本方法具有操作简便的特点，可应用于实际案件纤维物证的鉴定，为通过纤维截面特征区分相同种类、不同工艺纤维提供科学依据。     

显微光谱成像技术在汽车油漆截面检验中的应用

目的对汽车多层油漆的横截面进行分层和比对研究。方法运用显微光谱成像技术对收集的12个省市623个汽车漆片样本进行分层,并对截面结构相同或相似的油漆样本进行了区分。结果 623个油漆样本均可以分层,分析出漆层为两层及以上的油漆样本数占总数的87.26%;截面结构相同或相似的油漆样本能够多层同时区分。结论该方法具有科学及实用价值,检验结果可靠,可见光谱成像技术完全可运用拓展到微量物证的检验中。     

纤维的检验及其新方法

纤维是刑事案件、交通事故等各类案件中可利用的重要物证。本文总结了纤维检验中。从外观形态、化学性质、光学性质、热性能、分子结构等角度检验纤维种类。尤其是单根纤维检验的方法：评价了双折率法、小角度激光散射法、差热分析法、裂解气相色谱法、红外光谱法在实际应用中的检测效能：展望了激光拉曼光谱法等新方法的应用情况。     

付立叶红外显微镜及其附件检验微量纤维

通过付立叶红外显微镜及其附件ATR、金刚石池对微量纤维进行检验,从而达到对微量或痕量纤维准确确定其种属和比对检验是否相同的目的,方法准确、快捷、可靠.     

pMCT118位点扩增片段长度多态性及其应用

本文报道了对98例中国人 pMCT118位点扩增片段长度多态性的等位基因频率调查及有关法医生物物证检验问题的研究。用多聚酶链反应、小型聚丙烯酰胺凝胶电泳和银染方法,在12h 内检测低至1ngDNA 的 pMCT118位点扩增片段长度多态性。已发现22个等位基因,大小分布在340～780bp 之间,基因频率为0.005～0.3,杂合度为79%。对6个家系22名相关个体的分析符合孟德尔定律。探讨了微量检材样品制备和对混合斑、单根毛囊、唾液等生物检材的法医应用。对20个实际案例进行了检验。     

一种红外微量样品简易压片法

压片制样法是红外光谱检验最常用的样品处理法,适用于纤维、粉末、固态颗粒等多种样品的制备。测试这样的样品无溶剂峰的干扰,测试后的薄片可以保存,但实际应用中需要固定模具,操作繁琐,稍有不慎便会导致制样失败,且压制微量样品时必须再更换微量压模器,给工作带来不便。笔者在工作中摸索出一种简易压片法,该法无需特制模具,操作简便,成功率高,可压制几十毫克至几十微克不同量的样品,压制微量样品也不必更     

荧光光谱法鉴别棉纤维上的染料

棉纤维是法庭科学实验室中常见的微量物证之一。由于常用于棉纤维染色的染料种类较多,有直接染料、硫化染料、还原染料、冰染染料、活性染料等,所以在对棉纤维进行检验时,为了得到准确、可靠的结论,除应检验纤维的种类、形态外,还必须对棉纤维上的染料进行检验。曾有人用荧光光谱法对毛腈纤维上的染料和棉纤维上的还原染料进行了分析。本文采用荧光光谱法测定了红色、蓝色共30种棉纤维上的染料提取液,为纤维上染料的分析测定建立了一种灵敏度高,操作简便,快速的方法。     

显微红外光谱仪与显微拉曼光谱仪对纺用无色单根纤维的检测

目的研究常见纺用单根无色纤维的有效鉴别方法。方法使用显微红外光谱仪、显微激光拉曼光谱仪研究7大类纺用单根无色纤维的分子光谱。结果显微红外光谱仪、显微激光拉曼光谱仪能有效区分包括棉、粘胶、羊毛、丝、聚酰胺、聚丙烯腈和聚酯在内的7种纤维,是检测单根纤维的有效手段。785nm激发光源是显微激光拉曼光谱仪研究这7类纤维的最佳波长。但由于纺用纤维生产过程的标准化,仅依据红外或者拉曼的峰位置区分同种类、不同产地纤维的效果一般。结论显微红外光谱仪、显微激光拉曼光谱仪是鉴别常见纺用单根无色纤维的有效方法。     

显微红外光谱仪与显微拉曼光谱仪对纺用无色单根纤维的检测

目的研究常见纺用单根无色纤维的有效鉴别方法。方法使用显微红外光谱仪、显微激光拉曼光谱仪研究7大类纺用单根无色纤维的分子光谱。结果显微红外光谱仪、显微激光拉曼光谱仪能有效区分包括棉、粘胶、羊毛、丝、聚酰胺、聚丙烯腈和聚酯在内的7种纤维,是检测单根纤维的有效手段。785nm激发光源是显微激光拉曼光谱仪研究这7类纤维的最佳波长。但由于纺用纤维生产过程的标准化,仅依据红外或者拉曼的峰位置区分同种类、不同产地纤维的效果一般。结论显微红外光谱仪、显微激光拉曼光谱仪是鉴别常见纺用单根无色纤维的有效方法。     

国外微量物证检验研究进展

本文根据近年来国外法庭微量物证检验方面的研究成果,从检验对象、检验技术及发展趋势三个方面总结了当前国外微量物证的研究现状。介绍了近年来国外法庭科学家在常见的微量物证如油漆、纤维、玻璃等的检测方法和检测技术,尤其重点介绍了一些新技术如电感耦合等离子体原子发射光谱技术（ICP/AES）、微波辅助消融和等离子光谱技术（OES...     

Preferential extraction of hydrocarbons from fire debris samples by solid phase microextraction

Headspace analysis by extraction/GC-MS is a common method of detecting volatile hydrocarbon accelerants in fire debris samples. Solid-phase microextraction was tested to determine if there is selective extraction of chemically distinct compounds. It was found that both the polydimethylsiloxane (PDMS) and Carboxen/PDMS solid phase microextraction fibers show preferential extraction of aliphatic or aromatic compounds from the headspace depending on fiber type and temperature. The Carboxen/PDMS fiber type showed particular (although not exclusive) selectivity for extraction of aromatic hydrocarbons. Other experimental considerations of SPME are noted.     

Dilute solution viscometry of single polyester fibers

Efflux times were measured for dilute solutions of short lengths of ten single polyester fibers by micro capillary viscometry using a 50-μl charge. Limiting viscosity numbers (intrinsic viscosities) and molecular weights were calculated for each fiber by a single-point method. Efflux times were measured for three of the fibers after they were subjected to two different laundering procedures and outdoor exposure. The viscometric method was unsuitable for fiber identification but was shown to be highly discriminating for the comparison of fibers of similar commercial origins.     

Principal component analysis and analysis of variance on the effects of Entellan New on the Raman spectra of fibers

During the forensic examination of textile fibers, fibers are usually mounted on glass slides for visual inspection and identification under the microscope. One method that has the capability to accurately identify single textile fibers without subsequent demounting is Raman microspectroscopy. The effect of the mountant Entellan New on the Raman spectra of fibers was investigated to determine if it is suitable for fiber analysis. Raman spectra of synthetic fibers mounted in three different ways were collected and subjected to multivariate analysis. Principal component analysis score plots revealed that while spectra from different fiber classes formed distinct groups, fibers of the same class formed a single group regardless of the mounting method. The spectra of bare fibers and those mounted in Entellan New were found to be statistically indistinguishable by analysis of variance calculations. These results demonstrate that fibers mounted in Entellan New may be identified directly by Raman microspectroscopy without further sample preparation.     

运用光谱成像技术区分同色棉纤维

目的研究同色棉纤维的检验方法。方法运用成像光谱法对红、蓝、黑3个颜色组的棉纤维进行区分。结果红色棉纤维的鉴别率为62．2％，蓝色棉纤维的鉴别率为77．8％，黑色棉纤维的鉴别率为69．6％。结论实验结果表明，光谱成像技术可以区分大部分同色棉纤维。拓宽了纤维检验的方法，解决了同色棉纤维的区分问题，该方法能够用于对微量同色棉纤维的快速鉴别。     

Determination of disperse dyes on polyester fibers by UHPLC–Orbitrap MS

The determination of fiber dyes is important in forensic investigations. Although a variety of fiber dyes detection methods have been established, the sensitive and accurate determination of trace fiber dyes remains a challenge due to the possible interferences caused by complex environmental matrix and various fiber additives. Orbitrap mass spectrometry (Orbitrap MS) is a type of high-resolution mass spectrometry with high qualitative accuracy and detection sensitivity which highly meet the identification requirements of fiber dyes in real cases. However, the application of Orbitrap MS in fiber dye analysis is limited. In this regard, this study used polyester fiber, which is the most commonly-found fiber in forensic cases, as a model and established a UHPLC–Orbitrap MS method to analyze disperse dyes on polyester fibers. Using the optimized UHPLC–Orbitrap MS method, nine disperse dyes were accurately identified and well separated, and the limits of detection ranged between 0.1 ng/mL and 5.0 ng/mL. The developed method was applied to analyze actual fiber samples, and dyes from single fibers of 1 mm in length could be accurately detected. The established method is sensitive, accurate, and demonstrates good application prospects.     

Forensic analysis of bicomponent fibers using infrared chemical imaging

The application of infrared chemical imaging to the analysis of bicomponent fibers was evaluated. Eleven nominally bicomponent fibers were examined either side-on or in cross-section. In six of the 11 samples, infrared chemical imaging was able to spatially resolve two spectroscopically distinct regions when the fibers were examined side-on. As well as yielding characteristic infrared spectra of each component, the technique also provided images that clearly illustrated the side-by-side configuration of these components in the fiber. In one case it was possible to prepare and image a cross-section of the fiber, but in general the preparation of fiber cross-sections proved very difficult. In five of the 11 samples, the infrared spectra could be used to identify the overall chemical composition of the fibers, according to a published classification scheme, but the fiber components could not be spatially resolved. Difficulties that are inherent to conventional "single-point" infrared spectroscopy, such as interference fringing and sloping baselines, particularly when analyzing acrylic type fibers, were also encountered in the infrared chemical image analysis of bicomponent fibers. A number of infrared sampling techniques were investigated to overcome these problems, and recommendations for the best sampling technique are given. Chemical imaging results were compared with those obtained using conventional fiber microscopy techniques.     

High-performance liquid chromatography-ultraviolet-visible spectroscopy-electrospray ionization mass spectrometry method for acrylic and polyester forensic fiber dye analysis

A critical point of comparison between a fiber collected from a crime scene and a fiber from a known source is the color. Fiber dye analysis using thin-layer chromatography or ultraviolet (UV)-visible (Vis) microspectrophotometry provides useful, although limited, data for comparison. High-performance liquid chromatography-electrospray ionization mass spectrometry (LC/MS) overcomes these limitations by integrating chromatography, ultraviolet-visible spectroscopy, and mass spectrometry into a single instrument. In order to evaluate the applicability of the LC/MS to forensic fiber dye analysis, a multi-stage chromatographic method using acidified water and acidified acetonitrile was developed that separated and identified a mixture of 15 basic and 13 disperse dye standards. The LC/MS also detected and analyzed dyes extracted from individual 0.5 cm acrylic and polyester fibers, demonstrating its applicability to this type of analysis. With regard to the analysis of disperse dyes in polyester fibers, the replacement of pyridine with acetonitrile in the extraction system allowed direct injection of the extracts into the LC/MS. The advantage of the LC/MS over other instrumental methods of textile dye analysis is demonstrated by the analysis and differentiation of three black acrylic fibers: two fibers had similar UV-Vis spectra but were differentiated with chromatography and two had similar UV-Vis spectra and chromatograms but were differentiated using the mass spectrometer.     

A quantitative differentiation method for acrylic fibers by infrared spectroscopy

Absorbance peak areas of nitrile (2240 cm(-1)), carbonyl (1730 cm(-1)) and CH (1370 cm(-1)) groups were obtained for 48 colorless acrylic fibers by infrared (IR) microspectroscopy. The carbonyl signal, related to the comonomers most commonly used in acrylic fibers, was ratioed against the nitrile and CH bands, pertaining to the backbone of the polymer chains. The ratios A1730/A2240 and A1730/A1370, a relative measure of the comonomer content in the fiber, were used to differentiate the samples. A decrease in the crystallinity of fibers has been noted with increasing comonomer content. Relative standard deviation (R.S.D.) of the ratios were 1 and 3% for repetitive analyses on the same location and along the length of the same single fiber, respectively. When different fibers of the same sample were examined, results were reproducible within 6%. This simple method can greatly enhance the evidential value of colorless acrylic fibers, being able to discriminate them and thus helping the Court to better assess their significance.     

A Novel Method for Identifying Shahtoosh

Shahtoosh, the down hair of the Tibetan antelope (Pantholops hodgsonii), is the noblest and most expensive wool in the world. The population of the animal has declined dramatically due to commercial poaching for the fiber. Traditional inspection for detection of shahtoosh has been performed by microscopic analysis. We developed a TaqMan real‐time PCR‐based DNA analysis method for identifying shahtoosh fibers. A set of probe and primers for the mitochondrial 12S ribosomal RNA gene that binds specifically to Tibetan antelope DNA was designed. A signal was detected with sensitivity to the 1:10,000 dilution of shahtoosh DNA. A fiber mixture of 1% of shahtoosh mixed with cashmere and even a single fiber can be detected with this method. The method is faster, more cost‐effective and more sensitive than other traditional sequencing methods and can be directly applied to identify shahtoosh and its processed products, which will be of value in illegal trade investigations.     

Mahaim纤维致猝死5例

寻找心源性猝死者的病理形态学诊断依据。采用本组建立的心传导系统检查法 ,对 16 5例无心外器官疾病猝死者的心脏 ,作心传导系统的组织学检查。发现 5例存在心传导系统Mahaim纤维 ,全部均为束室束型。本组Ma haim纤维的形态学与房室束 (HB)或左束支 (LBB)相似 ,胞体横径在 10～ 35 μm左右 ,胞浆丰富 ,色淡红染 ;来自HB的纤维胞体呈细条状 ,核居中 ;来源于LBB的则按其始发点不同自上而下逐渐变大 ,纵切细胞未见分叉 ,但部分细胞周围见有一薄层结缔组织包围。分析结果表明 ,Mahaim纤维是可致猝死的房室传导旁路。