Fatal Methemoglobinemia Due to Acute Inhalation of Methyl Nitrite in an Industrial Accident

Methyl nitrite is suggested to cause methemoglobinemia by generating methemoglobin, which may be lethal when the methemoglobin concentration exceeds 70%. However, intoxication with methyl nitrite is seldom reported compared with that with other nitrites. Here, we present an industrial accident involving methyl nitrite inhalation during its synthesis process that resulted in three fatalities and one survivor. The autopsy revealed conspicuous blue-gray discoloration in various parts of the body, including the skin, airway mucosa, vessels, brain, heart, and among other areas. The toxicological tests on the deceased showed methemoglobin concentrations in the blood over the lethal level and increased nitrite ion levels in the blood, gastric contents, liver, and lung tissue compared with those in control samples. The cause of death was determined to be methemoglobinemia-induced hypoxia due to methyl nitrite inhalation. This report provides evidence that in methyl nitrite intoxication, exposure duration has a significant influence on the postmortem changes and likelihood of a fatal outcome may be related to the age of the victim. More attention is required regarding the industrial hazards of this substance.     

Quick Screening of Crystal Methamphetamine/Methyl Sulfone Exhibits by Raman Spectroscopy

Abstract: The analysis of mixtures of “crystal meth” (usually comprised of methyl sulfone [MS] and methamphetamine [MA]) by gas chromatography‐mass spectrometry (GCMS) is routine in many forensic drug laboratories. The utilization of Raman spectroscopy for the identification of such mixtures quickly and without the need for a separation technique is discussed. Samples were dissolved in water and Raman spectra of the resulting aqueous solutions were collected. By comparing these spectra to spectra of methylsulfone and MA mixtures of known composition, an indication of the composition of the sample can be obtained in only a few minutes. This spectral comparison also can be used as a semi‐quantitative analysis of MA concentrations in such exhibits.     

Methyl tert‐Butyl Ether (MTBE) Detected in Abnormally High Concentrations in Postmortem Blood and Urine from Two Persons Found Dead Inside a Car Containing a Gasoline Spill

Two deep frozen persons, a female and a male, were found dead in a car. There had been an explosive fire inside the car which had extinguished itself. On the floor inside the car were large pools of liquid which smelled of gasoline. The autopsy findings and routine toxicological analyses could not explain the cause of death. Carboxyhemoglobin levels in the blood samples were <10%. Analysis with a headspace gas chromatography revealed methyl tert‐butyl ether (MTBE) concentrations of 185 mg/L (female victim) and 115 mg/L (male victim) in peripheral blood. The urine MTBE concentrations were 150 mg/L and 256 mg/L, respectively. MTBE is a synthetic chemical which is added to gasoline as a fuel oxygenate. Gasoline poisoning is likely to be the cause of the death in these two cases, and MTBE can be a suitable marker of gasoline exposure, when other volatile components have vaporized.     

Ultrafast Amplification of DNA on Plastic Microdevices for Forensic Short Tandem Repeat Analysis

The majority of microfluidic devices used as a platform for low‐cost, rapid DNA analysis are glass devices; however, microchip fabrication in glass is costly and laborious, enhancing the interest in polymeric substrates, such as poly (methyl methacrylate) (PMMA), as an inexpensive alternative. Here, we report amplification in PMMA polymerase chain reaction (PCR) microchips providing full short tandem repeat profiles (16 of 16 loci) in 30–40 min, with peak height ratios and stutter percentages that meet literature threshold requirements. In addition, partial profiles (15 of 16 loci) were generated using an ultrafast PCR method in 17.1 min, representing a ~10‐fold reduction in reaction time as compared to current amplification methods. Finally, a multichamber device was demonstrated to simultaneously amplify one positive, one negative, and five individual samples in 39 min. Although there were instances of loci dropout, this device represents a first step toward a microfluidic system capable of amplifying more than one sample simultaneously.     

Forensic Analysis of MTBE Contamination Using Basic Hydrogeologic Concepts

Contamination of groundwater with petroleum hydrocarbons and additives, such as methyl tert‐butyl ether (MTBE), is often linked to the leaking product distribution system of gas stations. In very few cases is it know if and when a leak occurred and how much product was released to the environment. In the absence of direct evidence, a careful analysis of the available data, such as contaminant breakthrough at receptor wells or discrepancies in the product inventory data, may provide evidence about the nature of the release, its timing and magnitude. Using a MTBE contamination site in the formerly glaciated New England region as an example, two possible release scenarios (slow, long‐term release vs. spill) were examined. Of the two scenarios, the slow release could be ruled out as the sole source even though there was no direct evidence for a spill. The analysis of hydraulic test results together with chemical data further permitted to estimate when such an undocumented spill might have occurred. Analyses of the data also allowed these results to be compared to that of a prior transport and fate modeling study. Good agreement and consistency for contaminant travel times was confirmed. This forensic analysis demonstrates that applying basic hydrogeologic principles can aide in the reconstruction of contamination events while providing more readily understandable and defendable evidence relative to complex models. Conceptually, the approach described herein is transferable to other sites with similar hydrogeologies.     

MDMA前体PMK methyl glycidate的定性检验

目的利用PMK methyl glycidate来合成胡椒基甲基酮(piperonyl methyl ketone,PMK),可进一步合成3,4-亚甲二氧基甲基苯丙胺(MDMA)。本文首次报道了中国大陆出现的PMK methyl glycidate,并应用气相色谱-质谱联用(GC-MS)和核磁共振(NMR)技术对化合物结构进行了分析与确证。方法样品分别用甲醇和DMSO-d₆提取后,使用GC-MS和NMR进行检测。结果通过GC-MS分析测得化合物的质谱特征碎片和保留时间信息,并对氢谱碳谱的信号峰进行归属,确定了化合物结构。结论该方法简便可靠,能用于PMK methyl glycidate的检验。     

甲状腺滤泡上皮细胞DNA含量与死亡时间的相关性

目的探讨甲状腺滤泡上皮细胞平均DNA含量变化与死亡时间(PMI)的相关性。方法采用甲基绿-派洛宁(MG-P)染色法结合图像分析技术,测定尸体甲状腺滤泡上皮细胞平均DNA含量变化值,并对其数据进行统计学分析。结果甲状腺滤泡上皮细胞平均DNA含量随死后经过时间的延长而加速降解。平均DNA含量各指标(平均灰度、目标面积、目标面积比)与PMI之间的决定系数R2分别为0.960、0.987、0.988和0.990(P<0.001)。结论尸体甲状腺滤泡上皮细胞平均DNA含量与PMI之间具有明显相关性,甲基绿-派洛宁(MG-P)染色法结合图像分析技术测定在研究甲状腺滤泡上皮细胞DNA含量变化方面具有一定优势。     

Comparative analysis of gamma-hydroxybutyrate and gamma-hydroxyvalerate using GC/MS and HPLC

This paper describes two analytical techniques used to separate and quantify gamma-hydroxybutyrate (GHB) and gamma-hydroxyvalerate (GHV). The first technique was a N,O-bis(trimethylsilyl)triflouro-acetimide-trimethylchlorosilane derivatization, followed by gas chromatography/mass spectrometry analysis using an HP-5 capillary column at a rate of 1.0 mL/min with a run time of 9.25 min. This technique was found to be sensitive (LOD 1 pg on column) and gave a low average error (5%) in a beverage study. When supplemented by a surrogate spike, the method yielded 97% analyte recovery from beverages. The second technique was high-performance liquid chromatography/UV (HPLC/UV) using a C-18 column with a (20:80% v/v) methanol:dibasic phosphoric buffer (10 mM, pH 3) at a rate of 1.00 mL/min with a run time of 7.5 min. UV detection occurred at 254 nm. This method was found to be less sensitive (LOD 0.05 microg on column) for direct analysis of aqueous samples. To remove interferences seen in the beverage study, a liquid-liquid extraction before HPLC analysis was tested. However, a decreased sensitivity (LOD 100 microg on column) and irreproducible peak profiles resulted.     

Fatty Acid Profiles for Differentiating Growth Medium Formulations Used to Culture Bacillus cereus T‐strain Spores

Microbial biomarkers that indicate aspects of an organism's growth conditions are important targets of forensic research. In this study, we examined fatty acid composition as a signature for the types of complex nutrients in the culturing medium. Bacillus cereus T‐strain spores were grown in medium formulations supplemented with one of the following: peptone (meat protein), tryptone (casein protein), soy protein, and brain–heart infusion. Cellular biomass was profiled with fatty acid methyl ester (FAME) analysis. Results showed peptone cultures produced spores enriched in straight‐chained lipids. Tryptone cultures produced spores enriched in branched‐odd lipids when compared with peptone, soy, and brain–heart formulations. The observed FAME variation was used to construct a set of discriminant functions that could help identify the nutrients in a culturing recipe for an unknown spore sample. Blinded classification tests were most successful for spores grown on media containing peptone and tryptone, showing 88% and 100% correct identification, respectively.