高效液相色谱法-蒸发光散射检测器同时测定肝乐颗粒中黄芪甲苷和芍药苷的含量

目的 采用高效液相色谱-蒸发光散射检测器(high performance liquid chromatography-evaporative light scattering detector, HPLC-ELSD)建立肝乐颗粒中黄芪甲苷和芍药苷的含量测定方法。方法 以水和甲醇分别为流动相A和流动相B,在Hypersil ODS XB-C18柱(4.6 mm×250 mm,5 μm)上进行梯度洗脱。洗脱程序：0~5 min,A 60%;6~10 min,A 25%,11~18 min,A 10%;流速：1.2 mL/min;柱温：30 ℃。ELSD参数优化：增益值分别设为1、2、3;漂移管温度分别设为50、70、90、110 ℃;载气流量分别为1.2、1.6、2.0、2.4 L/min。结果 通过优化参数,在增益值为2,漂移管温度为90 ℃和载气流量为2.0 L/min时,对芍药苷和黄芪甲苷的含量检测结果最佳。芍药苷和黄芪甲苷的平均加样回收率分别为99.58%、100.37%,RSD分别为2.32%、1.21%。结论 该方法简便、准确、灵敏度高、重现性好,所优化的ELSD参数及建立的HPLC-ELSD法适合肝乐颗粒中芍药苷和黄芪甲苷含量的同时测定。     

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。     

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.     

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.     

Differentiation between inks of the same brand by infrared luminescence photography of their thin-layer chromatograms

A case is reported involving a U.S. Treasury check with an altered amount payable. The ink in the alteration and the ink in the endorsement signature were compared with ink from three Skilcraft ball pens all having Skilcraft black ink ball pen refills. Infrared luminescence photography of their thin-layer chromatograms revealed differences between the inks in the three pens.     

Simple determination of carboxyhemoglobin by double wavelength spectrophotometry of absorbance difference and the comparison with gas chromatographic method

This paper describes the spectrophotometric determination of carboxyhemoglobin (CO-Hb) in blood on the basis of double wavelength spectrophotometry of absorbance difference. Absorbance measurements are made in the 500–600 nm region at a blood dilution of 100–200-fold. Blood is diluted with a solution containing Na₂S₂O₄ to provide two components of CO-Hb and deoxyhemoglobin (deoxy-Hb). Absorbance difference at the two wavelengths at which deoxy-Hb has the same absorbance reflects only the CO-Hb component because the opposite component is nulled out of the mixture. After measurement of the absorbance difference, the measuring solution is saturated with CO gas to make all Hb derivative CO-Hb and remeasured at the same wavelengths. The percent of CO-Hb is considered the absorbance difference ratio. Results obtained by the present method was in satisfactory agreement with gas chromatographic data in blood not containing methemoglobin (Met-Hb). Comparative experiments using the gas chromatographic method and the present method were performed with samples containing Met-Hb. However, while there is a deficiency in the gas chromatographic method when the samples contain Met-Hb, the results of the present method were in close agreement with theoretical values when samples are mixed with CO-Hb, O₂-Hb and Met-Hb. Advantages of this method are that it is simple and accurate, standard curve or equation for calculation and accurate dilution are not necessary.     

肝中杀鼠酮硅藻土提取高效液相色谱检测法研究

目的建立肝中杀鼠酮的硅藻土提取方法和高效液相色谱检测法。方法取0．5g肝匀浆，加69／5HC10。沉淀蛋白，准确取1／2上清液倒入装有3．1g硅藻土的层析柱中，用10mL二氯甲烷或乙醚洗脱，洗脱液中加入安定作为内标，水浴浓缩，用0．2mL甲醇定容，供高效液相色谱分析。结果提取率分别为98．1％和99．9％，检出限分别为14ng／mL和13ng／mL。结论该方法简便、快速、提取率高，可作为法医毒物常规检测手段。