酮洛芬注射液在乳牛体内的残留消除研究

为建立牛乳中酮洛芬的液相色谱-串联质谱(LC-MS/MS)检测方法,牛乳样品经甲醇提取,C18色谱柱分离,采用正离子模式,多反应监测,内标法定量。结果表明,牛乳中酮洛芬的检出限为1μg/kg,定量限为5μg/kg,在5~200μg/kg范围内线性关系良好,相关系数大于0.99。在25~100μg/kg添加水平的回收率为93.3%~107.5%,批内、批间相对标准偏差分别为1.72%~5.46%、1.13%~7.04%。该方法高效、灵敏、准确,可作为牛乳中酮洛芬的检测方法。选用20头健康的泌乳期荷斯坦乳牛,高产、低产各10头,以3 mg/kg剂量肌内注射给药,每天1次,连用3 d,分别于每次给药后第2、15小时采集乳样。每次给药后2 h牛乳中可检出酮洛芬,最高质量分数为(38.43±3.90)μg/kg,停药后15 h均未检出。所有时间点牛乳中酮洛芬质量分数的实测结果均低于加拿大规定的最高残留限量50μg/kg,建议弃乳期为0 d。     

Combined Collection and Analysis of Inorganic and Organic Gunshot Residues

Gunshot residue (GSR) analysis and their interpretation provide crucial information on a criminal investigation involving the use of firearms. To date, several approaches have been proposed for the implementation of a combined sampling and analysis of inorganic (IGSR) and organic GSR (OGSR). However, it is not clear at this stage if concurrent analyses of both types of residue might be detrimental to the analysis of IGSR currently applied in forensic laboratories. Thus, this work aims to compare and evaluate three different protocols for the combined collection and analysis of IGSR and OGSR. These methods, respectively, involve the use of a modified stub (with two halves, one for the detection of IGSR and the other for the analysis of OGSR); the sequential recovery of GSR with two stubs mounted with different adhesives (double-sided carbon tape and Tesa® TACK) and the sequential analysis of IGSR and OGSR from a single carbon stub following carbon deposition. The detection of IGSR was carried out using SEM-EDX, while OGSR analysis was performed using ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS). Obtained results for experiments performed using Geco Sinoxid^® ammunition indicated that sequential analysis was the most suitable protocol for the combined collection and analysis of both IGSR and OGSR. A higher number of inorganic (characteristic and consistent) particles and higher concentrations of ethylcentralite, N-nitrosodiphenylamine, diphenylamine, and nitroglycerin were recovered with this method.     

Nondestructive Differentiation of Polyester Single White Fibers Using Synchrotron Radiation Microbeam X-ray Fluorescence Spectrometry with Vertical Focusing

In this study, the nondestructive differentiation of individual white polyester clothing fibers was accomplished via synchrotron radiation microbeam X-ray fluorescence (SR-μ-XRF) analysis. SR-μ-XRF with vertical focusing is a useful nondestructive method for the analysis of a single polyester clothing fiber. Kirkpatrick–Baez (KB) mirror was used to vertically focus 20 keV X-rays for the analysis of 22 individual white polyester fibers taken from clothing commonly sold in Japan. SR-μ-XRF with a vertical focused 2 μm (V) × 300 μm (H) beam was approximately 12.8 times more sensitive than SR-XRF with an unfocused 300 μm (V) × 300 μm (H) beam for the detection of elements in single fibers. The minimum detection limits (MDLs) of the SR-μ-XRF method were 8.15 ppm for Cl and 0.06 ppm for Br. In addition to Ti in TiO₂ delustering agents, Zr and Nb impurities in the delustering agents were detected in individual fibers. Sb from a polymerization catalyst and Co from a transesterification catalyst were also detected in individual fibers. Comparing the Ti K_β/Sb L_α,β and Zr K_α/Nb K_α X-ray intensity ratios was a useful way to distinguish individual clothing fibers, and 98% of the fibers were differentiated when additional trace elements were used as discrimination indicators.     

The Effect of Temperature and Exposure Time on Stability of Cholesterol and Squalene in Latent Fingermarks Deposited on PVDF Membrane

Cholesterol and squalene are fatty materials of latent fingermarks that can be utilized for dating methodologies and visualization techniques. Previous studies have suggested these compounds undergo degradation in fingermarks as a function of time (days) and light at ambient temperature. However, studies assessing how their composition changes at low and high temperatures over short periods of time (hours) have not been published previously. Here, we performed quantitative analysis of cholesterol and squalene in natural fingermark residue using PVDF membrane, after exposure to a range of temperatures (−20 to 100°C) for 4 and 8 h. We found that levels of both fatty materials remained constant at −20 to 60°C, but both showed significant reduction at 100°C, over short exposure times. These results indicate that cholesterol and squalene are detectable at −20 to 60°C, whereas at 100°C or higher, both are lost due to rapid thermal degradation.     

Sample Mining and Data Mining: Combined Real-Time and Retrospective Approaches for the Identification of Emerging Novel Psychoactive Substances

Novel psychoactive substances (NPS) are synthetic drugs that pose serious public health and safety concerns. A multitude of NPS have been identified in the United States, often implicated in forensic investigations. The most common and effective manner for identifying NPS is by use of mass spectrometry and the true utility lies within nontargeted acquisition techniques. During this study, a liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) assay was developed, validated, and implemented for forensic toxicology testing. A SCIEX TripleTOF™ 5600 + with SWATH^® acquisition was used. Resulting data were compared against an extensive library database containing more than 800 compounds. The LC-QTOF-MS assay was applied to the reanalysis of biological sample extracts to discover emergent NPS. More than 3,000 sample extracts were analyzed, and more than 20 emerging NPS were detected for the first time. Among these were isopropyl-U-47700, 3,4-methylenedioxy-U-47700, fluorofuranylfentanyl, N-methyl norfentanyl, 2F-deschloroketamine, 3,4-methylenedioxy-alpha-PHP, eutylone, and N-ethyl hexedrone.     

自制海洛因标准品在常用有机溶剂中稳定性研究

目的 研发海洛因标准品及优化分析方法,以对云南缴获海洛因样本提纯制备成的自制海洛因对照品在常用有机溶剂中的稳定性进一步研究.方法 采用内标及GC、GC/MS方法,通过对提纯制备的海洛因在5种有机溶剂中冷藏保存后含量的变化,观察海洛因在常用有机溶剂中的稳定性.结果 乙醇、三氯甲烷及乙腈为溶剂的自制海洛因对照品储备液,保存30天时间范围内海洛因含量未发生明显变化;以丙酮作为溶剂的自制海洛因对照品储备液,在7至30天时间范围内,海洛因含量明显升高;以甲醇作为溶剂的自制海洛因对照品储备液,在0小时至30天时间范围内,海洛因含量一直呈明显的下降趋势.结论 乙醇、三氯甲烷及乙腈可以作为海洛因样品储备液溶剂使用,丙酮、甲醇不适合作为海洛因样品储备液溶剂使用.     

The analysis of casework sized alloy fragments by inductively coupled plasma-optical emission spectrometry (ICP-OES) using discrete nebulisation

A discrete nebulisation technique has been developed for the multi-element analysis of 100-μl solution droplets by inductively coupled plasma-optical emission spectrometry (ICP-OES). The technique increases analytical speed and uses very small solution volumes with only a slight degradation in detection limits when compared to continuous solution introduction.To evaluate its suitability in casework, small alloy fragments were produced by cutting with a hacksaw, sample division and filing. The analysis of fragments from two different brasses indicated that quantitative data could be obtained from fragments as small as 10 μg. The accurate determination of lead, a non-homogeneous constituent of leaded brasses, required sample sizes an order of magnitude greater. Analysis of an alloy of fine grain structure (copper-nickel) demonstrated that quantitative data could be obtained from samples weighing a few micrograms or less.     

高效液相色谱-质谱法测定人尿液中乙基葡萄糖醛酸苷

目的建立高效液相色谱-质谱法测定人尿液中乙基葡萄糖醛酸苷。方法取空白人尿液加入EtG-D5内标工作液和冷甲醇（4℃）,经涡旋、离心,取上清液于水浴氮气吹干,以沉淀杂质,采用Agilent Zorbax Bonus-RP色谱柱分离,以乙腈∶0.1%甲酸水溶液（5∶95）为流动相,采用负离子模式质谱检测,在选择离子监测模式下进行定性和定量测定。结果尿液中EtG在50～5 000ng/mL范围内线性关系良好,检出限为18ng/mL,方法回收率为90.2%～101.7%,相对标准偏差小于10%。结论所建方法简便,具有较高的回收率和精密度,适用于尿液中EtG的检测。     

东北亚油气合作的现实选择:来自中国在中亚的成功经验

东北亚和中亚地区凭借丰富的油气资源,在世界能源版图中的地位日渐上升。近年来,中亚地区油气合作发展迅速,但是在资源总量上更具优势的东北亚油气合作之路却充满曲折。在地区性统一能源市场形成之前,政府间多边协调机制仍然是东北亚油气合作的现实选择。中国在互利双赢的理念指导下,以良好的政治互信为基础,以油气运输管线为纽带,通过以双边合作为主、双边合作带动多边合作的方式,循序渐进地稳步推进了与中亚国家的油气合作。因此,中国在推动地区油气合作方面积累了一定的成功经验,提高了驾驭复杂局面的能力,理应在推进东北亚油气合作方面发挥更积极的作用。     

Detection of Gamma-Hydroxybutyric Acid in Various Drink Matrices via AccuTOF-DART*

Abstract: A new screening method for detecting gamma-hydroxybutyric acid (GHB) in drink matrices, using the IonSense, Inc. (Saugus, MA) direct analysis in real time (DART) ion source coupled to a JEOL exact mass time-of-flight mass spectrometer (AccuTOF), was validated and compared with the current screening methodology. The DART ion source allows for analysis of samples under ambient conditions with little to no sample preparation. Fifty drink specimens were spiked at levels of 1, 2, 3, and 4 mg/mL GHB, and analyzed on the AccuTOF-DART. Positive detection of GHB occurred for each of the samples at each concentration level, giving 100% accuracy for the samples tested. Twenty-five of the 50 drink specimens were spiked at 1 mg/mL GHB and tested using a color test known as the GHB Color Test #3. Only two of these 25 specimens tested positive for the presence of GHB, giving only 8% accuracy. Implementation of this new methodology as a screening tool for GHB analysis will quickly eliminate negative specimens allowing the examiner to focus analysis time on those that screened positive.