用dHPLC技术检测线粒体DNA编码区单核苷酸多态性

目的研究线粒体DNA(m tDNA)编码区单核苷酸多态性,建立检测m tDNA编码区单核苷酸多态性(SNP)的变性高效液相色谱(dHPLC)方法。方法设计针对线粒体DNA编码区nt10287-10679及nt8507-8805引物,应用dHPLC技术检测其序列多态性。结果100例中国汉族无关个体中,m tDNA nt10287-10679检出13个SNP位点,13种单倍型,基因多样性(H)为70.79%,偶合概率(P)为29.92%;m tDNA nt8507-8805检出10个SNP位点,12种单倍型,H为70.42%,P为30.28%;两段序列联合起来共检出23个SNP位点,23种单倍型,H为84.14%,P为16.70%。结论所建立的dHPLC方法可用于快速、准确地检测m tDNA编码区序列多态性;m tDNA编码区多态性位点作为m tDNA控制区多态性位点的补充,联合应用可以提高m tDNA的个体识别能力。     

Detection of Cutting Agents in Drug‐Positive Seized Exhibits within the United States

The following report summarizes a study performed on seized drug exhibits collected in two U.S. states to evaluate the presence and identification of cutting agents. Aliquots of seized drug materials from Kentucky (n = 200) and Vermont (n = 315) were prepared using a dilute‐and‐shoot procedure. Initial analysis was performed using gas chromatography–mass spectrometry (GC‐MS) followed by analysis using liquid chromatography quadrupole time‐of‐flight mass spectrometry (LC‐QTOF). Active compounds detected overall included caffeine (31.0%), quinine/quinidine (24.7%), levamisole (11.6%), acetaminophen, (8.2%) and procaine (8.2%). These compounds were found with several drugs of abuse, such as heroin, fentanyl, methamphetamine, and cocaine. This novel information about cutting agents used to dilute or alter drugs of abuse is important to criminal investigations and in the management of acute intoxications at health centers. However, common methodologies for analysis and standard reporting practices frequently do not include cutting agents, resulting in lacking or inadequate information regarding prevalence of these substances.     

固相萃取/气相色谱法检测全血中的扎来普隆

目的建立全血中扎来普隆的固相萃取/气相色谱检测方法。方法采用Oasis HLB固相萃取柱,5%甲醇水淋洗,二氯甲烷洗脱,GC/NPD定量检验,GC/MS定性检验,并对检测条件进行考察。结果扎来普隆与血中杂质分离良好,平均萃取回收率达89%以上,最低检出限20ng/mL,50～2000ng/mL内线性良好,相关系数R2=0.9945,日内RSD为3.1%～4.2%,日间RSD 5.8%～6.7%。结论该方法操作简便快速,提取回收率高,重现性好,提取物杂质少,可用于实际案件的检验。     

Availability of target odor compounds from seized ecstasy tablets for canine detection

The aim of this study was to compare seized samples of 3,4-methylenedioxy-N-methylamphetamine (MDMA) pills, used to train law enforcement detection canine teams, to determine what differences exist in the chemical makeup and headspace odor and their effect on detectability. MDMA solutions were analyzed by liquid chromatography-mass spectrometry. Analysis of these samples showed a wide variance of MDMA (8-25%). Headspace SPME-GC/MS analysis showed that several compounds such as 3,4-methylenedioxyphenylacetone and 1-(3,4-methylenedioxyphenyl)-2-propanol are common among these MDMA samples regardless of starting compound and synthesis procedure. However, differences, such as the level of the various methylenedioxy starting compounds, were shown to affect the overall outcome of canine detection, indicating the need for more than one MDMA training aid. Combinations of compounds such as the primary odor piperonal in conjunction with a secondary compound such as MDP-2-OH or isosafrole are recommended to maximize detection of different illicit MDMA samples.     

Analysis and discrimination of electrical tapes: part II. Backings

The backings of 90 black electrical tapes were analyzed to evaluate the chemical components of these films, the ability of individual techniques to discriminate samples, and the ability of the techniques combined to distinguish samples. The techniques utilized and their respective discrimination results were stereomicroscopy and physical measurements, to include observation of surface features of the backing, width, and thickness measurements (c. 64%); Fourier transform infrared spectroscopy (FTIR) using a microscope accessory (c. 83%); pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS; c. 81%); and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS; c. 87%). Ninety-four percent of the backings were discriminated through this combination of analytical methods. Finally, evaluating these results in conjunction with previously published data on the analysis of the adhesives from the same set of electrical tapes provided an overall discrimination of nearly 96%.     

结核分枝杆菌三价DNA疫苗的体液免疫与细胞免疫应答

为研究结核分枝杆菌Ag85B、MPT64和MPT83抗原DNA疫苗在奶牛体内诱导的免疫应答,以PJW4303为载体,构建了上述3种抗原基因的三价DNA疫苗。采用阴离子交换色谱方法提取3种质粒,混合后添加佐剂DDA免疫3月龄荷斯坦奶牛3次,采用ELISA法检测免疫奶牛的特异性抗体效价。利用双抗夹心ELISA定量测定免疫奶牛各月的IFN-γ浓度。结果显示,纯化后的DNA疫苗经质量检验达到动物免疫试验的要求;免疫前奶牛体内特异性抗体为阴性;三免后第30天MPT83、Ag85B和MPT64特异性抗体效价达到最高,均值分别为1∶3 200、1∶2 560和1∶2 880;同时免疫奶牛MPT83、Ag85B、MPT64三种蛋白诱导产生的IFN-γ在三免后第30天达到最高,分别为(630.25±94.45)、(341.65±76.75)、(51.38±9.80)pg/mL,阴性对照组PBS的IFN-γ浓度为(6.48±20.88)pg/mL。每个月的阴性对照与3种抗原相比,差异均极显著(P<0.01)。证实该三价核酸疫苗能同时诱导机体产生细胞免疫应答和体液免疫应答,可能有利于增强疫苗对结核病的抗性。     

The use of filtered light for the evaluation of writing inks analyzed using thin layer chromatography

Thin layer chromatography (TLC) is a scientific methodology that can be used to compare and characterize ink formulations. Occasionally, when evaluating chromatographic profiles on a TLC plate with ambient light, different ink formulations, or the same inks from different batches, may appear indistinguishable. The use of filtered light can be very effective to illuminate characteristics that are not readily apparent with ambient light. There are a diverse number of components commonly found in writing inks, and it may be that some of them respond to particular wavelengths of energy that are not visible to the unaided eye (i.e., colorless). There has been very little information published that addresses the use of filtered light for evaluating TLC plates. Twenty-nine ballpoint writing ink samples were selected for TLC analysis. Further evaluation using an alternate light source, coupled with the appropriate filter, proved to be an effective means for definitive discrimination in some cases.     

Development and validation of a simple GC-MS method for the simultaneous determination of 11 anticholinesterase pesticides in blood--clinical and forensic toxicology applications

Anticholinesterase pesticides are widely used, and as a result they are involved in numerous acute and even fatal poisonings. The aim of this study was the development, optimization, and validation of a simple, rapid, specific, and sensitive gas chromatography-mass spectrometry method for the determination of 11 anticholinesterase pesticides (aldicarb, azinphos methyl, carbofuran, chlorpyrifos, dialifos, diazinon, malathion, methamidophos, methidathion, methomyl, and terbufos) in blood. Only 500 μL of blood was used, and the recoveries after liquid-liquid extraction (toluene/chloroform, 4:1, v/v) were more than 65.6%. The calibration curves were linear (R(2) ≥ 0.996). Limit of detections and limit of quantifications were found to be between 1.00-10.0 and 3.00-30.0 μg/L, respectively. Accuracy expressed as the %E(r) was found to be between -11.0 and 7.8%. Precision expressed as the percent relative standard deviation was found to be <9.4%. The developed method can be applied for the investigation of both forensic and clinical cases of accidental or suicidal poisoning with these pesticides.     

The Characterization of 3,4-Dimethylmethcathinone (3,4-DMMC)

Analogs and derivatives of traditional illicit drugs are ever increasing in variety and creativity. Staying abreast of the new developments is a constant challenge for every forensic laboratory. Recently, a seizure from Australian Customs Service presented our laboratory with the designer cathinone 3,4-dimethylmethcathinone (3,4-DMMC). Gas chromatography/mass spectrometry (GC/MS), liquid chromatography/mass spectrometry (LC/MS), nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy, and ultraviolet (UV) spectrophotometry were employed to analyze the spectroscopic characteristics of this cathinone. As an analog, 3,4-DMMC exhibits similar if not identical IR and UV profiles to mephedrone (4-MMC) and methcathinone; however, the retention time from GC is unique as expected, and the electron impact fragmentation pattern is consistent with the fragmentation pattern of other cathinones. The chemical shifts of the carbons and hydrogens were assigned by both one- and two-dimensional NMR techniques, while the molecular weight was confirmed by LC/MS.     

中性墨水笔墨迹中甘油成分的气相色谱分析及历时性变化初探

目的对中性墨水笔墨迹中甘油成分和随时间变化规律进行研究。方法利用气相色谱法分析了含有甘油溶剂成分的中性墨水笔字迹墨迹,并对甘油成分含量相差较大的字迹样本的变化规律进行了研究。结果得到了3种字迹墨迹中甘油成分随字迹形成时间变化的关系曲线。结论曲线变化规律表明,书写时间6个月的中性墨水笔墨迹中甘油成分的含量变化出现拐点,6个月以后甘油成分的含量基本趋于不变。