高效液相色谱-蒸发光散射法分析人和动物油脂种属

目的采用反相高效液相色谱-蒸发光散射方法分析人和动物油脂种属。方法采集人体和7种动物(猪、牛、羊、鸡、鸭、鹅、鱼)油脂,丙酮溶解后直接进样分析,色谱柱为C18反相柱,流动相为二氯甲烷-乙腈(30∶70 V/V),流速1.0mL/min,蒸发光散射检测器进行检测。结果采用本文方法检测POSt、MMP、StPSt、OPO 4种甘油三酯组分分离效果良好;用于油脂分析,其主要组分高级脂肪酸三甘酯均得到了有效分离,色谱峰的保留时间和相对峰面积比的重现性好;与动物油脂比较,人体油脂具有独特的色谱特征;动物之间色谱特征也有差异。结论采用本文高效液相色谱-蒸发光散射法检测油脂,可根据人体油脂与动物油脂色谱特征的差异为油脂种属鉴定提供依据。     

GC/MS法检测全血中的奥氮平

目的采用乙睛-甲醇混合溶剂提取、气质联用分析法检测全血中奥氮平。方法针对奥氮平特性,在加入稳定剂硫代硫酸钠条件下采用乙睛-甲醇混合溶剂提取法,采用GC/MS分析法,对全血中的奥氮平进行定性、定量分析。并对提取介质、酸碱度、稳定剂种类及用量进行了考察。结果采用本文方法在奥氮平为1～400μg/mL浓度范围内呈良好的线性关系(r2=0.999 8,n=5),检出限为1.0ng,方法平均回收率可达66.5%(RSD=2.5%)。日内RSD为2.1%～3.9%,日间RSD为2.9%～4.5%。选择乙腈∶甲醇(V∶V=8∶2)混合溶剂进行液-液提取,稳定剂为300mg硫代硫酸钠。结论本文方法可用于全血中奥氮平检测,在相关案件检验中选择使用。     

同时裂解甲基化气相色谱法快速鉴别人体脂肪及动植物油脂

采用同时裂解甲基化气相色谱法（SPM－GC），首次分析人体脂肪，并且观察人体脂肪、猪、鸡、牛、羊脂和豆油中7种脂肪酸的组份含量变化。根据7种主要脂肪酸（肉豆蔻酸、棕榈酸、棕榈油酸、硬脂酸、油酸、亚油酸和亚麻酸）甲酯的百分含量可有效地进行鉴别。结果表明：通过SPM－GC法分析油脂，可将传统的油脂酯化法时间由2个多小时缩短到1分钟左右。数据C．V．％＜4％，最小检测量为1．Oμg。最佳比例四甲基氢氧化按（TMAH）甲醇液（TMAH：甲醇＝1：10，V／V），可消除油脂中多不饱和脂肪酸的异构化和降解。     

裂解毛细管柱色谱法检验微量油斑迹中常见高沸点矿物油脂的方法研究

采用居里点裂解毛细管柱色谱法,氢火焰离子化检测器,利用色谱峰“指纹轮廓图”分析法,特征峰的相对保留值(RRT)和相对百分含量比值(RCP)鉴别10种常见高沸点矿物油脂油斑迹,均获得满意结果。该法灵敏度高,鉴别能力强,数据重现性好,适用于犯罪现场微量油斑迹的检验,最小检测量为5μg。     

基于高通量测序进行无创产前亲子鉴定的可行性

目的初步探讨基于高通量测序进行STR分型的技术方法应用于无创产前亲子鉴定的可行性。方法选择13个STR基因座(6个常染色体STR基因座,6个Y染色体STR基因座,1个性别判定基因座),进行复合PCR扩增和高通量测序文库构建后,采用Ion PGM400高通量测序平台进行测序,并采用自主研发软件NGS-STR genotyper(perl脚本)进行STR分型,本文简称上述过程为NGS-STR分型。对13个母子配对混合样本(母亲:儿子=2%~50%)、1组家系样本进行了上述NGS-STR分型,旨在(1)了解其在混合样本中的灵敏度及分型情况;(2)了解其在无创产前亲子鉴定中的应用可能性。结果 (1)当混合样本中低组分(儿子)的比例超过8%,所有基因座均可检出低组分的STR信息;(2)对1例血浆样本进行NGS-STR分型,共计69.2%的基因座可检出胎儿的STR基因型信息,且所有检出基因座均符合孟德尔遗传规律。结论初步证明了NGS-STR分型技术具有进行无创产前亲子鉴定的可行性。     

UPLC-MS/MS法监测污水中甲卡西酮稳定性试验研究

目的通过正交试验比较甲卡西酮在不同溶剂pH值、浓缩温度、保存时间和保存温度提取条件下的稳定性,建立适合污水中甲卡西酮稳定测定的提取制备方法用于超高压液相色谱质谱联用仪的检测。方法在甲卡西酮检测过程中设置4个因素(提取溶剂pH值、浓缩温度、保存时间、保存温度)进行考察,每个因素选择3个水平,然后采用L9(3~4)进行正交试验,提取液使用液相色谱三重四极杆串联质谱仪(Exion LC/QTRAP 6500)检测,以甲卡西酮m/z=105.1的子离子峰面积作为定量指标,采用SPSS 16.0统计软件进行数据分析找出最佳条件。结果正交试验结果分析表明,提取溶剂pH=2.0,保存时间0d,保存温度-20℃,浓缩温度60℃为最佳提取条件,并根据该条件进行了方法学考察,结果表明甲卡西酮在1ng/L～500ng/L浓度范围内线性良好,提取回收率90%,RSD5.33%,基质效应6.52%,RSD0.31%,均符合相关标准要求。结论本研究通过正交试验筛选到的甲卡西酮制备方法有利于其稳定检测,适用于质谱的定性定量分析,可用于对污水中甲卡西酮成分的监测工作。     

高效液相色谱法测定卡西酮

目的建立卡西酮的高效液相色谱检测方法。方法采用UPLC-DAD分析方法。分析柱:Agilent ZorbaxSB-Phenyl柱(250mm×4.6mm,5μm),流动相为三氟乙酸(pH 3.5)∶乙腈为85∶15,流速0.2mL/min,检测波长254nm。结果卡西酮在0.5～1 000μg/mL浓度范围内线性关系良好R2=0.999 4,日内与日间保留时间和峰面积的标准偏差(RSD)均<1.06%,检出限为0.068μg/mL,平均回收率95.9%。结论本方法峰形好,分离度好,线性范围良好,回收率高,适用于刑事案件中卡西酮的定性定量分析。     

创周围六种金属痕迹的显现

<正> 利用金属印痕彩色显现方法,显现金属凶器遗留在衣服创口周围的金属成份及分布,从而确定凶器特征,现介绍如下。一器材与试剂器材紫外线灯、玻璃或塑料皿、印(放)相纸、竹夹子、上光机、量杯等。试剂 (1)溶解剂:12%氨水,10～25%醋酸,酒石酸缓冲液;(2)显色剂:红氨酸甲醇饱和液,0.2%玫红酸钠(钾)水溶液,0.05%铁氰化钾盐酸溶液;桑色素甲醇饱和液,5%     

LC-MS/MS同时测定人血浆中氯氮平、奥氮平和米氮平

目的 建立人血浆中氯氮平、奥氮平、米氮平的液相色谱-串联质谱(LC-MS/MS)检测方法.方法 血浆中的氯氮平、奥氮平、米氮平用乙醚液-液萃取,采用Agilent Zorbax SB-C18柱(2.1mm×l50mm,5 μm),电喷雾离子源,正离子检测,多反应监测方式进行定量分析,卡马西平作为内标.结果 氯氮平、奥氮平和米氮平的检测限为0.41～0.92ng/mL,质量浓度在10.0～2000.0ng/mL范围内线性良好(r≥0.9924),平均萃取回收率在65.7%～94.2%,日内、日间精密度RSD≤6%(n=5).结论 该方法专属性强、灵敏及准确,可以适用于法庭与临床毒物分析.     

细胞裂解法和磁珠法在法医DNA检验中的对比

目的 比较细胞裂解法和磁珠法在法医DNA检验中的效果,探讨两种方法在法医学检验中的运用。方法 使用细胞裂解法和磁珠法获取不同数量的THP-1细胞的基因组DNA并使用实时定量PCR检测DNA含量。使用细胞裂解法和磁珠法对不同稀释倍数的人血进行STR分型检测。结果 当THP-1细胞数量为100、400和800个时,使用细胞裂解法提取的DNA含量分别为(1.219±0.334)、(5.081±0.335)、(9.332±0.318) ng;使用磁珠法提取的DNA含量分别为(1.020±0.281)、(3.634±0.482)、(7.896±0.759) ng,在THP-1细胞数量为400和800个时,细胞裂解法提取的DNA含量高于磁珠法(P<0.05)。使用细胞裂解法和磁珠法检测不同稀释倍数人血的STR分型时灵敏度相近,在血样稀释100、300和500倍时均能获取完整的STR分型,血样稀释700倍时,均无法检出完整STR分型。使用细胞裂解法无法检出未稀释人血的STR分型。结论 细胞裂解法操作方便,能最大程度保留模板DNA,有望适用于微量血痕检验。     

Abuse of smoking methamphetamine mixed with tobacco: II. The formation mechanism of pyrolysis products

The pyrolysis products of smoking methamphetamine mixed with tobacco were determined by gas chromatography (GC) and GC/mass spectrometry (GC/MS) methods. The mainstream smoke contained methamphetamine (14.5% of the initial methamphetamine), phenylacetone (3.1%). N-cyanomethylmethamphetamine (1.9%), trans-beta-methylstyrene (1.7%), N-formylmethamphetamine (1.5%), and other products (each less than 1%). The amount of each pyrolysis product in the sidestream smoke was less than that in the mainstream smoke by a factor of over 5, except for methamphetamine (10.5%) and N-formylmethamphetamine (1.4%). The formation mechanism of these products was investigated, by use of a pyrolyzer, from the standpoint of the material, pyrolysis temperature, and pyrolysis atmosphere. Although several products (for example, dimethylamphetamine and trans-beta-methylstyrene) were formed by thermal self-decomposition of methamphetamine alone, most of the products, except N-cyanomethylmethamphetamine, were formed chiefly by the thermal reaction of methamphetamine with cigarette components. The formation of N-cyanomethylmethamphetamine required air and a high pyrolysis temperature. Air and a high pyrolysis temperature generally accelerated the formation of the pyrolysis products.     

A method for forensic identification of vegetable oil stains--rapid analysis of carboxylic acids with methyl esterification using purge-and-trap gas chromatography/mass spectrometry.

A simple method using purge-and-trap gas chromatography/mass spectrometry (P&T-GC/MS) for forensic examination of oil stains was studied. Carboxylic acids, chosen as target components for discrimination of oil samples, were extracted from stains with ether, methyl esterified by tetramethylammonium hydroxide, and analyzed by P&T-GC/MS. Vegetable oils were discriminated according to their carboxylic acid compositions. Carboxylic acid composition was independent of the substrate material of the stain. Although the carboxylic acid composition of the oil changed on exposure to sunlight, identification of oil was possible for oil stains that had been in the shade, if analysis was made within 20 days.     

Effect of Substrate Interferences from High‐Density Polyethylene on Association of Simulated Ignitable Liquid Residues with the Corresponding Liquid

The effect of substrate interferences from high‐density polyethylene (HDPE) on the ability to associate an ignitable liquid residue with the corresponding liquid standard, using statistical procedures, is demonstrated. Gasoline, kerosene, and lighter fluid, at three different evaporation levels, were spiked onto HDPE and subsequently burned to generate simulated ignitable liquid residues (ILRs). Samples were extracted using a passive headspace procedure and analyzed by gas chromatography–mass spectrometry. The total ion chromatograms were subjected to data pretreatment procedures prior to principal components analysis and Pearson product moment correlation. Using the combination of these statistical procedures, simulated ILRs were successfully associated with the corresponding liquid type, despite the presence of compounds inherent to the HDPE substrate, as well as those resulting from pyrolysis of the substrate.     

The forensic analysis of soil organic by FTIR

In order to elucidate the discriminating power of various soil analytical techniques, over 100 soils samples were analyzed using conventional analysis (i.e., color, percent organic and density gradient) and a novel FTIR technique. The FTIR technique involves collecting a spectrum of a soil sample that has been oxidatively pyrolysed, and therefore all organic have been degraded. This spectrum is subtracted from the spectrum of the same sample that contained the organic prior to pyrolysis. This resultant IR spectrum represents the organic portion of the sample. The use of organic components increases the discrimination in soils that are otherwise similar. We have illustrated the usefulness of this technique by selecting four soil samples, which have identical Munsel color values but can be discriminated by subtractive ETIR. We propose that the ETIR spectra of the organic portion of soil serves a useful purpose in forensic investigations.     

Chemical composition of fingerprints for gender determination

This work investigates the chemical nature of fingerprints to ascertain whether differences in chemical composition or the existence of chemical markers can be used to determine personal traits, such as age, gender, and personal habits. This type of information could be useful for reducing the pool of potential suspects in criminal investigations when latent fingerprints are unsuitable for comparison by traditional methods. Fingertip residue that has been deposited onto a bead was extracted with a solvent such as chloroform. Samples were analyzed by gas chromatography/mass spectrometry (GC/MS). The chemical components identified include fatty acids, long chain fatty acid esters, cholesterol and squalene. The area ratios of ten selected components relative to squalene were calculated for a small preliminary experiment that showed a slight gender difference for three of these components. However, when the experiment was repeated with a larger, statistically designed experiment no significant differences between genders were detected for any of the component ratios. The multivariate Hotelling's T2 test that tested all ten-component ratios simultaneously also showed no gender differences at the 5% significance level.     

The determination by gas chromatography with atomic emission detection of total sulfur in fuels used as forensic evidence

In Japan, taxed diesel fuel from non-taxed fuel oil-A is illegally produced by removing coumarin, which is added as a non-taxed marker. The coumarin is removed using concentrated sulfuric acid and this produces a high viscosity and hazardous material, called "sulfuric acid pitch", as a by-product. This compound has a detrimental effect on the environment and is hazardous to humans. The actions have been associated with organized crime with the illegally gained taxes becoming financial bases. To discriminate legal and diesel oil from illegal product, the peak area ratio R(SC), the ratio of total sulfur to carbon (>C(14)), was used. R(SC) is calculated by the total areas of sulfur and carbon (>C(14)) from the gas chromatogram obtained by gas chromatography-atomic emission detection (GC-AED). Sulfur in legal diesel fuels is strictly regulated by a maximum limit, which was 50ppm (and is now 10ppm), but in the preparation of illegal diesel oil, in which coumarin is eliminated, sulfur cannot be removed. Therefore, the R(SC) of fuel oil-A and illegal fuel oil is over 15, whereas those for legal fuel oil and diesel fuel are under 2.0. Furthermore, these ratios do not change in weathering experiments. GC-AED was applied to an actual arson case and was found to be effective for the determination of total sulfur in trace amounts of accelerants detected in fire debris at the arson scene, and hence was effective for the characterization of the ignitable liquids used.     

Latent fingerprint detection using a scanning Kelvin microprobe

Electrochemical interactions between latent human fingerprints and metal surfaces in ambient air are investigated using a scanning Kelvin microprobe. Inorganic salts present in sweat deposited at fingerprint ridges locally depassivate the metal surface producing a Volta potential decrease of greater than 200 mV. Volta potential patterns may persist for months and prints may be visualized by potential mapping, even when overcoated with a polymer layer. Because the Volta potential differences are produced by involatile salts they persist when the organic components of the fingerprint residue have been volatilized by heating to 600 degrees C.     

碱催化裂解气相色谱法检测白色毛纤维的研究

本文利用气相色谱仪,配以CZ—100热丝裂解器和FID检测器,对25种白色毛纤维进行比对分析,系统考察了织物在使用过程中经过日晒、汗渍的侵蚀、皂洗的处理后,对碱催化裂解气相色谱法分析毛纤维的影响,达到鉴别不同厂家、产地以及不同生产工艺白色毛纤维的目的。此方法可靠、快速、有效、便于操作,为各类案件中同类白色毛纤维的鉴定提供了一种切实可行的方法。     

The effect of metal salt treatment on the photoluminescence of DFO-treated fingerprints

Ninhydrin developed fingerprints can be enhanced by treatment with a zinc or cadmium salt. The resulting fingerprint luminescence has been attributed to the induced coplanarity of the bicyclic indanedione rings of Ruhemann's purple due to complexation with the metal ions. This paper explores whether this effect also occurs in the 1,8-diaza-9-fluorenone (DFO)-amino acid adduct (1), formed from the reaction of DFO with amino acids. Molecular modeling studies of (1) indicate a relatively small out-of-plane angle of 24 degrees. 1H NMR studies indicate (1) is asymmetric about the C2 axis in contrast to what has been previously reported. Little, if any, enhancement of luminescence was observed with Zn, Cd, Ru or Eu treated DFO developed latent fingerprints. This lack of enhancement was also borne out by solution luminescence studies. Given this lack of enhancement of luminescence, solutions of (1) and the four metal ions above were analyzed by electrospray mass spectrometry (ESMS). This indicated the formation of predominantly 1:1 complexes of (1) with both Zn and Cd, and the 2:1 complex with ruthenium. No evidence of a Eu complex was found by ESMS.