普通红外光谱法快速检验化学修饰后的毛发

该研究的目的是建立一种无损快速检验化学修饰后毛发的方法。将样品清洗后,染色使用仪器：傅立叶红外光谱仪水平ATR装置,扫描范围设定为4,000厘米-1到650厘米-1,扫描次数设定为32次,分辨率设定为4厘米-1;分别取适量毛发样品,置于水平ATR仪锗晶体表面上,并压平;样品扫描,采集样品红外光谱谱图;红外光谱谱图处理,基线自动校准,9点平滑处理。结果28种样品实验结果表明,重现性较好,能够区分不同处理的样品。     

Determination of barbiturates in hair samples by using a validated UHPLC-HRMS method: application in investigation of drug-facilitated sexual assault

In recent years,benzodiazepines and benzodiazepine-like drugs are the most common substances associated with drug-facilitated sexual assaults(DFSA);however,barbiturates are also detected occasionally.Segmental hair analysis provides useful information on the historic pattern of drug use,enabling differentiation between single exposure in DFSA cases and chronic use.However,sensitive and specific methods for barbiturate analysis in hair samples are needed.Herein,we present an ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry(UHPLC-HRMS)method for qualitative and quantitative determination of seven barbiturates in hair samples.Firstly,a hair strand was decontaminated and then freeze-milled in liquid nitrogen.Next,50mg of powdered hair was extracted with methanol in an ultrasonic bath for 10 min in the presence of 10 ng phenobarbital-d5.The supernatant was dried under nitrogen gas,and the pellet was dissolved in 100 μL mobile phase.Afterwards,10 μL of the suspension was injected into the UHPLC-HRMS system.The present method involved two UHPLC conditions for determination of barbiturates(I)and identification of the structural isomers amobarbital and pentobarbital(II).This method showed satisfactory linearity in a range of 0.02–20.00 ng/mg for UHPLC conditions I and II,both with a high determination coefficient(0.9991–0.9999).The selectivity,intra-and interday precision,accuracy and matrix effect of the method were acceptable.Next,the validated method was applied to investigate an authentic DFSA case.Hair samples(black,approximate 25cm long)were collected 3 months after the assault,and the proximal segments(0–5 cm from the root;each segment was 1 cm long)were analysed.Amobarbital was detected at a concentration ofhair segment but not in the other segments.Thus,our method was successful in determining barbiturate concentration in human hair after a single-dose exposure,showing its potential for application in the investigation of DFSA cases.     

Accumulation of explosives in hair--Part 3: Binding site study

This study extends previous work on the sorption of explosives to the hair matrix. Specifically, we have studied the interaction of 2,4,6-trinitrotoluene (TNT) and triacetone triperoxide (TATP) as a function of chemical pretreatment with acetonitrile, neutral and alkaline hydrogen peroxide, methanolic KOH and potassium permanganate, and the morphological changes that accompany these treatments. While differences in vapor pressure can account for quantitative differences between TNT and TATP sorption, both are markedly affected by the chemical rinses. Examination of the hair surface shows different degrees of smoothening following rinsing, suggesting that the attachment to hair is largely a surface phenomenon involving the 18-methyleicosanoic acid lipid layer. Density functional theory calculations were employed to explore possible nucleation sites of TATP microcrystals on the hair. We conclude that some of the sites on melanin granular surfaces may support nucleation of TATP microcrystals. Moreover, the calculations support the experimental finding that dark hair adsorbs explosives better than light hair.     

COⅠ基因微条形码技术在毛发种属鉴定中的应用

目的利用COⅠ基因微条形码技术对哺乳动物毛发进行种属鉴定。方法设计一对哺乳动物COⅠ基因微条形码通用引物,利用共同区PCR技术对来自于哺乳纲5个目11个种属的实验动物毛发DNA进行扩增,并对扩增产物进行双向引物测序,将测序结果进行拼接后所得的基因序列输入BOLD数据库进行同源性比对。结果本研究设计的微条形码通用引物能够对所有种属实验动物毛发DNA进行扩增,扩增片段长度147 bp。数据库同源比对结果显示最匹配物种与实验动物种属相符,除狮同源匹配度为98.99%外,其他实验动物同源匹配度均为100%,且狮种内遗传距离1%,种间遗传距离大于种内遗传距离十倍,可以进行种属判定。结论建立的COⅠ基因微条形码技术能够快速准确地对哺乳动物毛发检材进行种属鉴定。     

基于紫外可见反射光谱法对染色头发的初步研究

紫外可见反射光谱法是一种快速无损检验的方法,本文从采样量、样品的固定等方面对染色头发进行紫外可见光谱检验方法进行了初步探索,使用紫外可见光谱仪的积分球附件可以对不同染发剂染色头发进行大致的分类鉴别。     

两组引物对无毛囊毛根的PCR-STR分型

目的了解无毛囊毛根的短扩增子引物和通用引物PCR-STR分型在法医实践中应用的可行性。方法应用5对Bulter设计的短扩增子引物D8S1179、D21S11、THO1、D16S539和VWA与其对应的STR通用引物,利用非变性PAGE,对无毛囊毛根进行PCR-STR分型的对比研究。结果短扩增子引物与通用引物对无毛囊毛根分型的正确率:D8S1179为11.4%和17.1%、D21S11为3.7%和5.9%、vWA为22.2%和33.3%、THO1为9.3%和5.6%、D16S539为0和9.2%。毛根的短扩增子引物和通用引物部分STR分型出现了干扰结果的Ladder-like背景条带。结论在对无毛囊毛根检材进行通用引物和短扩增子引物PCR-STR分型时,五个STR位点分型检测的成功率有限,还需注意Ladder-like条带的干扰。     

吸毒者毛发中苯环己哌啶的串联质谱分析

应用串联质谱方法分析吸毒者毛发中苯环己哌啶(phencyclidine,PCP)国内尚未见报道。在整个分析过程中,不需要用溶剂将PCP从毛发中提取出来。从PCP吸毒者毛发中只检测到PCP,没有检测出其代谢产物。被动吸收试验发现毛发可从水溶液中紧密吸收PCP,这类似于身体对PCP的结合。检测结果表明:PCP可被非吸毒者的毛发吸收,且较为稳定。     

毒品与毛发的结合及其影响因素

毛发毒品的分析在毒品检验中具有独特优势,而毛发与毒品的结合状况及毒品聚集于毛发的机制影响其检测的准确性和灵敏性。对毒品与毛发的结合位点、毒品与毛发结合的差异性因素以及外界因素对毒品与毛发结合的影响进行了综述。     

Rapid presumptive "fingerprinting" of body fluids and materials by ATR FT-IR spectroscopy

Human body fluids and materials were evaluated using attenuated total reflectance Fourier transform infrared spectroscopy. Purified proteins, cosmetics, and foodstuffs were also assayed with the method. The results of this study show that the sampled fluids and materials vary in the fingerprint region and locations of the amide I peaks because of the secondary structure of the composite proteins although the C = O stretch is always present. The distinct 1016 cm(-1) peak serves as a signature for semen. The lipid-containing materials (e.g., fingerprints, earwax, tears, and skin) can also be easily separated from the aqueous materials because of the strong CH(3) asymmetric stretch of the former. Blood-saliva and blood-urine mixtures were also successfully differentiated using combinations of peaks. Crime scene investigators employing rapid, portable, or handheld infrared spectroscopic instruments may be able to reduce their need for invasive, destructive, and consumptive presumptive test reagents in evaluating trace evidence.     

Forensic Discrimination of Dyed Hair Color: II. Multivariate Statistical Analysis*,†

Abstract: This research is intended to assess the ability of UV–visible microspectrophotometry to successfully discriminate the color of dyed hair. Fifty‐five red hair dyes were analyzed and evaluated using multivariate statistical techniques including agglomerative hierarchical clustering (AHC), principal component analysis (PCA), and discriminant analysis (DA). The spectra were grouped into three classes, which were visually consistent with different shades of red. A two‐dimensional PCA observations plot was constructed, describing 78.6% of the overall variance. The wavelength regions associated with the absorbance of hair and dye were highly correlated. Principal components were selected to represent 95% of the overall variance for analysis with DA. A classification accuracy of 89% was observed for the comprehensive dye set, while external validation using 20 of the dyes resulted in a prediction accuracy of 75%. Significant color loss from successive washing of hair samples was estimated to occur within 3 weeks of dye application.