用Sep—Pak C18固相萃取柱快速提取净化氨基甲酸酯类农药

本文介绍了一种应用Sep—Pak C_(18)固相萃取柱从各类生物检材中快速提取净化9种氨基甲酸酯类农药的方法,并用大口径毛细管气相色谱进行分析。9种药物包括:速灭威、叶蝉散、灭多虫、灭除威、灭杀威、残杀威、巴沙、呋喃丹、西维因。萃取前,水基质检材用蒸馏水稀释;脏器检材加0.4N高氯酸溶液。用3ml氯仿/异丙醇(9:1)洗脱药物。水基质检材的回收率(尿、血浆、全血)在80—100％之间;脏器检材的回收率(肝、肾、脑)在66—100％之间。Sep—Pak C_(18)小柱用于尿和血浆样品时可反复使用。     

Equity, international trade and climate policy

The literature of welfare-maximising greenhouse gas emission reduction strategies pays remarkably little attention to equity. This paper introduces various ways to consider efficiency and equity simultaneously. Lower (higher) discount rates lead to higher (lower) emission reduction. Higher (lower) inequity aversion leads to higher (lower) emission abatement, unless one also considers the negative effects of OECD emission reduction on the exports of developing countries; in that case, the effect of inequity aversion is ambiguous. In the absence of international co-operation, higher (lower) risk aversion leads to lower (higher) emission abatement. With international co-operation, the effect of risk aversion is ambiguous because the higher risk aversion gives more weight to poorer regions and poorer generations. We analyse four ways to introduce compassion in a non-cooperative setting. If observed development aid is a guide, international altruism is small and has little impact on optimal emission control. If countries act as if they 'feel' but not 'physically experience' the climate impact of the most vulnerable country, optimal emission reduction increases, but not substantially so. However, if countries actually have to pay for the damage done, they would prefer to reduce their emissions to much lower levels. Finally, if countries pay as much for emission reduction as other countries suffer from climate change, (that is, if climate policy restores the income distribution to what it would have been without climate change), emissions are rapidly cut to very low levels.     

尸体腐败程度与死亡经过时间的实验研究

为了找出推测死亡经过时间的客观依据,应用健康的苏白猪为实验模型,进行尸体腐败程度与死亡经过时间研究,将模型分别放置在室内、室外及地下三个环境中,让尸体在自然的环境中发生腐败,详细记录尸体腐败所表现的现象,特别是腐败气体所产生的张力。实验发现,尸体腐败至软组织与骨骼全部分离、以及腐败残留物质的完全消失,与温度、湿度、降雨量、尸体与地面倾斜度、昆虫的寄生等有明显的关系。所得数据,为死亡经过时间的推测,积累了重要的参考依据。     

利用供热能力和天然气资源发展采暖用户改善首都环境

北京集中供热事业已取得较大的发展。降低民用建筑的综合热指标、改善供热二次管网和用户内部系统、改采暖收费包费制为计费制可以充分挖掘建筑供暖系统节能的潜力。合理利用天然气资源,发展采暖用户,可改善城市的环境质量。     

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.     

Differentiating writing inks using direct analysis in real time mass spectrometry

Writing ink analysis is used in establishing document authenticity and the sources and relative ages of written entries. Most analytical methods require removing samples or visibly altering the document. Nondestructive, in situ analysis of writing inks on paper without visible alteration is possible using mass spectrometry with a new ion source called Direct Analysis in Real Time. Forty-three different black and blue ballpoint, black fluid, and black gel inks were examined. Both dyes and persistent but thermally labile components of the inks contribute to the mass spectra, principally as protonated molecules [M+H](+). Numerous ink components were identified from the spectra. The spectra were placed in a searchable library, which was then challenged with two spectra from each of the 43 inks. The best match for each of the challenge spectra was correct for all but one ink, which matched with a very similar ink by the same manufacturer.     

A review of the analysis of vegetable oil residues from fire debris samples: analytical scheme, interpretation of the results, and future needs

This paper reviews the literature on the analysis of vegetable (and animal) oil residues from fire debris samples. The examination sequence starts with the solvent extraction of the residues from the substrate. The extract is then prepared for instrumental analysis by derivatizing fatty acids (FAs) into fatty acid methyl esters. The analysis is then carried out by gas chromatography or gas chromatography-mass spectrometry. The interpretation of the results is a difficult operation seriously limited by a lack of research on the subject. The present data analysis scheme utilizes FA ratios to determine the presence of vegetable oils and their propensity to self-heat and possibly, to spontaneously ignite. Preliminary work has demonstrated that it is possible to detect chemical compounds specific to an oil that underwent spontaneous ignition. Guidelines to conduct future research in the analysis of vegetable oil residues from fire debris samples are also presented.     

Concentration of carbon monoxide (CO) in postmortem human tissues: effect of environmental CO exposure

We studied how carbon monoxide (CO) is distributed within the human body through quantitation of CO concentrations in postmortem tissue samples from fatalities including possible CO exposure. Stored, frozen tissues were diced, sonicated in water, and 0.01-8.0 mg wet weight (ww) tissues were incubated with sulfosalicylic acid in CO-purged, septum-sealed vials. CO released into the headspace was quantitated by reduction gas chromatography. Mean tissue CO concentrations (pmol/mg ww) from subjects diagnosed to have no known CO exposure (control, N=14), died from fire (N=13), and CO asphyxiation (N=7), respectively, were: adipose (2;13;9), brain (3;13;65), muscle (15;97;297), heart (30;99;371), kidney (22;432;709, lung (54;690;2638), spleen (73;1366;3548), and blood (162;2238;5070). Carboxyhemoglobin concentrations were 1.4%, 25.2%, and 69.1% of total hemoglobin, respectively. We conclude that measurements of CO concentration in a variety of tissues can be used as markers for the degree of exogenous CO exposure and the identification of possible causes of death.     

Development of a GC-MS method for the simultaneous analysis of latent fingerprint components

Latent fingerprint residue is a complex mixture of organic and inorganic compounds. A full understanding of the composition of this mixture and how it changes after deposition is lacking. Three solvent systems were compared for the simultaneous extraction and derivatization with ethyl chloroformate of selected amino and fatty acids from a nonporous substrate (Mylar for subsequent analysis by gas chromatography-mass spectrometry. A solvent system comprised of sodium hydroxide, ethanol, and pyridine was found to be the most effective. This method was applied to the analysis of latent fingerprint residue deposited on Mylar and preliminary data are presented. Twelve amino acids (e.g., serine, glycine, and aspartic acid) and 10 fatty acids (e.g., tetradecanoic, hexadecanoic, and octadecanoic acids) were identified. The potential application of this method to further the understanding of latent fingerprint chemistry has been demonstrated.     

A mechanistic model for the superglue fuming of latent fingerprints

The use of superglue vapors to detect latent fingerprints, known as superglue fuming, is a chemical process that has not been fully described. The role of the fingerprint material in the process, leading to formation of methyl cyanoacrylate polymer at the site of the fingerprint, remains to be established. Films of liquid alkanes respond similarly to actual fingerprints in the fuming experiment. Their responses depended on the hydrocarbon used, viscosity, and film thickness. Aspects such as film thickness appear to be relevant for actual fingerprints as well. A model was proposed in light of these observations. The model compares the process with gas chromatography, in which molecules partition between the gas phase and a stationary phase. Aspects such as accumulation of superglue monomers by partitioning into a thin film (or wax) are consistent with the preferential response of fingerprints on surfaces relative to the background.