Practical Aspects of Analyzing Vegetable Oils in Fire Debris*

Abstract: Vegetable oils undergo burning, self‐heating, and spontaneous ignition, resulting in their presence in fire debris. As these processes can affect the fatty acid content of vegetable oils, it is important that debris be properly handled in order to obtain reliable and informative data. This research investigated changes in vegetable oil content as a result of storage conditions and different types of burning. Material spiked with vegetable oils and burned was stored under various long‐term conditions, and debris was tested by heating overnight using passive headspace concentration. Results indicated that refrigeration is ideal for fire debris samples suspected of containing vegetable oils and that including passive headspace concentration in the analytical scheme would not affect oils. Spontaneous ignition experiments were conducted to compare the effects of various burning processes on vegetable oil content. Vegetable oils that experienced nonpiloted ignition, self‐heating, and spontaneous ignition produced noticeably different chromatograms from those that underwent piloted ignition.     

“负责任外空行为”议程与太空安全机制新动向

近年来,太空安全环境发生急剧变化,各国太空军事化步伐加速,商业航天崛起,太空拥挤加剧,太空军民融合加深。在此背景下,英国于2020年发起一项名为“负责任外空行为”的太空军控新议程。该议程推出后,美国积极参与并试图将之导向一项自愿承诺禁止地基动能反卫星试验的国际协议,这意味着其太空军控立场的重大转向。美国意图借“负责任外空行为”议程干扰对手发展不对称反卫星手段、强化太空同盟、划定太空威慑“红线”、策应太空环境议题。“负责任外空行为”已成为太空安全机制领域最有影响力的议程,不仅因为其引发了大国间政治矛盾,还因其体现了太空安全机制的发展动向。在新的太空安全环境下,太空军事安全和民事安全的国际机制正交叉融合发展,各机制的议程模式将更加开放、参与者更加多样、控制行为的路径更加主流。     

Preparation and characterization of micro-bore wall-coated open-tubular capillaries with low phase ratios for fast-gas chromatography–mass spectrometry: Application to ignitable liquids and fire debris

Fast Gas Chromatography (GC) allows for analysis times that are a fraction of those seen in traditional capillary GC. Key modifications in fast GC include using narrow, highly efficient columns that can resolve mixtures using a shorter column length. Hence, a typical fast GC column has an inner diameter of 100–180 μm. However, to maintain phase ratios that are consistent with typical GC columns, the film thickness of fast GC stationary phases are also low (e.g., 0.1–0.18 μm). Unfortunately, decreased film thickness leads to columns with very low sample capacity and asymmetric peaks for analytes that are not sufficiently dilute. This paper describes micro-bore (50 μm i.d.) capillary columns with thick films (1.25 μm), and low phase ratios (10). These columns have greater sample capacity yet also achieve minimum plate heights as low as 110 μm. Hence, separation efficiency is much higher than would be obtained using standard GC columns. The capillary columns were prepared in-house using a simple static-coating procedure and their plate counts were determined under isothermal conditions. The columns were then evaluated using temperature programming for fast GC–MS analysis of ignitable liquids and their residues on fire debris exemplars. Temperature ramps of up to 75 °C min^?1 could be used and separations of ignitable liquids such as gasoline, E85 fuel, and lighter fluid (a medium petroleum distillate) were complete within 3 min. Lastly, simulated fire debris consisting of ignitable liquids burned on carpeting were extracted using passive headspace absorption-elution and the residues successfully classified.     

Assessing the potential fire risk of laundered fabrics after contamination with emollients using ATR-FTIR spectroscopy and chemometrics

Since 2010, more than 50 UK fire deaths, have been reported as linked with emollients. This prompted the Medicines and Healthcare products Regulatory Agency (MHRA) to issue advice on their safer use in 2018. The advice was in response to concerns raised by the National Fire Chiefs Council, coroners’ reports, and flammability tests. The test results show a significant reduction in ignition time of fabrics contaminated with paraffin-based and paraffin-free skin care product residues. The MHRA report also included advice on washing clothing and bedding at high temperatures but warned this may not remove all emollient residues. This paper reports on new research on the removal of skin care products from clothing investigated by laundering contaminated 100% cotton fabric at 30, 40 and 60 °C using both biological and non-biological based detergents. As part of the experiment, non-contaminated (blank) napkin samples were included in the wash experiments to assess the possible transfer from fabrics contaminated with emollients to uncontaminated clean fabrics during washing. Washed and dried fabrics were analysed using Attenuated Total Reflectance, Fourier Transform Infrared (ATR-FTIR) spectroscopy and further interpreted via principal component analysis (PCA) and network analysis. Results suggest that the majority of the 6% white soft paraffin-based lotion and paraffin-free cream were removed at all temperatures. Residues of 21% paraffin-based cream (6% light paraffin/15% white soft paraffin) remain, and more residues persist of the 100% paraffin-based ointment (5% light paraffin/95% white soft paraffin) after washing at 30, 40 and 60 °C. The wash experiments show unequivocal transfer of the 100% ointment from the contaminated napkins to clean control napkins placed within washes at 30 °C. Furthermore, residues of the ointment were observed within the machine drum, and washing machine door seal, though this did not cause secondary transfer to subsequent wash experiments. There were no differences observed when using biological versus non-biological detergents, nor when employing a pre-wash treatment in the removal of residues of the 21% cream and 100% ointment. These results suggest that a single application of an emollient when soaked and dried into a fabric is not removed by a single wash at 30, 40 or 60 °C. Instead, the residue remains a persistent potential fire risk and, its high paraffin content presents an additional fire risk via contamination of other fabrics.     

Chemical fingerprinting of petrochemicals for arson investigations using two-dimensional gas chromatography - flame ionisation detection and multivariate analysis

Two-dimensional gas chromatography is a mature, yet underutilised, separation technique able to provide the high resolution and peak capacity required for the study of complex samples such as oils. This paper presents the development of a comprehensive two-dimensional gas chromatography method with flame ionisation detection to profile easily available ignitable liquids commonly found in arson cases. The use of 2D chromatograms to profile different potential ignitable liquids was also explored for classification purposes. The chemical fingerprints produced were visually different and allowed the distinction of all the petroleum products tested. How the chemical fingerprints of each fuel changed over time was also assessed. Each sample was subjected to weathering with aliquots (1 mL) being collected every half hour for a five-hour period. Principal component analysis of the resulting data was able to demonstrate the effect of weathering for all fuels tested and established that it was still possible to differentiate between the various petrochemicals even after weathering. The work demonstrates an optimised analytical method for petrochemical product analysis that provides forensic scientists with a robust, fast and sensitive technique that can be used to determine not only which ignitable liquid was used in a fire (even after the fact) but also provide information on the specific fuel used.     

An Evaluation of Standardized Software for Processing GC/MS Data from Different Vendors' Instruments in a Forensic Laboratory

Forensic science laboratories perform analyses on a variety of materials using gas chromatography/mass spectrometry (GC/MS). Instruments from different vendors may be used, requiring analysts to be proficient in the use of multiple proprietary software packages for collecting and processing data. There is no standardized GC/MS software available that can acquire data from different vendors' instruments. However, there are third‐party processing software products that can import data files in different formats. The Centre of Forensic Sciences compared the data processing performance of one such product, ACD/MS Manager Suite, with three instrument vendors' software used for casework analysis. This product was tested for its compatibility with the existing software, its capability to load and present data, and to initiate searches of commercial libraries. The study shows that the MS Manager module provides a means for the forensic analyst to view, process, and report on data from different sources in one software package.     

企业C类员工的界定与管理

成功企业不仅是依靠有效的对A类、B类员工管理，更是依靠对C类员工的妥善处理。C类员工已经成为当前许多企业发展的障碍，而且相当多的企业对C类员工的界定和管理还处于靠感情、凭经验的层次上，不利于企业塑造一支优秀、高效的员工队伍。重视对C类员工的管理，建立一套行之有效的对C类员工的综合评价系统及管理制度是企业领导者的迫切、重要的任务。     

公安派出所消防监督管理工作的问题及对策

目前,很多公安派出所在消防监督方面都未依法行使职权和落实责任,现状堪忧。 公安派出所的消防监督管理工作,必须落实各项措施,建立长效机制。     

中美火箭残骸碰撞事件引发的法律责任问题思考

随着人类探索和利用外层空间的迅速发展,外空环境中的空间碎片急剧增加,发生空间物体损害责任事故的可能性随之日益增大。中美火箭残骸碰撞事件引发了作者对《空间物体造成损害的国际责任公约》能否有效应对当前责任事故的思考。基于空间开发新形势的需要,有必要对该公约进行修改和完善。     

谈中国关于空间碎片的立法不足

空间碎片现在已经成为外太空的主要污染源,各国航天事业需要共同攻破的课题。鉴于空间事故的屡次发生,对于空间碎片的探讨已提上日程。通过对中国参加的相关国际条约和中国国内空间的立法研究,发现国际条约中并没有具体的界定空间碎片的概念,更没有具体的条款来规范空间碎片,而国内关于空间的立法里亦没有提及到空间碎片。为了更好的发展我国航天事业,应该进一步完善我国国内空间立法,使航天事业的发展有法可依,有法可循。