纵火现场中汽油、煤油和柴油残留物的ATD／GC／MS法检测

目的为火场中汽油、煤油和柴油残留物的检测建立一种简便、高灵敏度的ATD／GC／MS检验方法。方法采用Tenax TA吸附管吸附富集检材中的汽油、煤油和柴油成分。然后用美国PE公司的ATD／GC／MS仪器进行全自动的解吸和分析检测。结果检材中汽油、煤油和柴油的检测极限分别达0．05、0.2、0．2pL／mL。结论该方法具解吸和分析检测过程自动化。操作简便快捷，检测灵敏度高。杂质干扰少等特点，可用于实际火场皆汽油、煤油和柴油残留物的检测。     

火场样品中汽油与稀释剂燃烧残留物的区分方法探讨

目的探讨火场样品中汽油与稀释剂燃烧残留物的区分方法。方法样品用ATD—GC—MS法检验,检验结果通过对芳烃、烷烃、茚满、和萘系列的4个特征离子色谱图与已知汽油和稀释剂作比较,并结合向量夹角法计算样品与汽油色谱指纹图的相似度来区分汽油与稀释剂残留物。结果个别品种的稀释剂燃烧残留物与汽油很相似,但彼此有某些差别。结论使用本方法,一般能将汽油与稀释剂燃烧残留物区分开。     

建立火场样品中汽油残留物ATD-GC-MS检验结果的评价方法

目的建立火场中汽油燃烧残留物ATD-GC-MS检验结果评价方法。方法将模拟燃烧样品用ATD-GC-MS法检验,检验结果通过对芳烃、烷烃、茚满、和萘系列的4个特征离子色谱图与已知汽油作比较,并利用向量夹角法计算样品与汽油色谱指纹图的相似度来对检验结果作评价。结果有汽油作助燃剂的模拟燃烧样品与汽油色谱指纹图的相似度一般大于90%,无汽油作助燃剂的样品则在60%以下。结论利用样品的4个特征离子色谱图与已知汽油作比较,并结合样品与汽油色谱指纹图相似度的计算,能对检验结果作出客观、可靠和准确的评价。     

自动热脱附气相色谱-质谱法分析火场助燃剂汽油成分

目的建立检验纵火案件现场燃烧残留物中助燃剂汽油成分的方法。方法利用自动热脱附技术对火场残留物中的助燃剂进行富集、浓缩、脱附后经气-质联用仪（GG-MS）分析。结果结合现场燃烧环境运用目标化合物法能够判定是否含有助燃剂汽油成分。结论该方法简便易行。     

固相微萃取与气相色谱仪联用技术在火场助燃剂检验中的应用

目的建立检验纵火案件现场燃烧残留物中助燃剂的一种方法。方法利用固相微萃取器吸附浓缩燃烧残留物中的挥发性气体,使用气相色谱仪对挥发性气体进行定性分析。结果固相微萃取与气相色谱仪联用能较好地对火场不同介质燃烧残留物中汽油、煤油、柴油等助燃剂进行种类认定。结论该方法简便易行。     

应用SPME—GC／MS／PFPD技术测定烃类及硫化物标记物鉴别汽油、煤油、柴油燃烧残留物

目的利用汽油、煤油、柴油等助燃剂中特殊的硫化合物类标记物,建立一种新型的火场助燃剂残留物分析方法。方法应用固相微萃取气质联用一脉冲火焰光度检测器（SPMBGC／MS／PFPD）技术同步测定烃类、芳香烃类及硫化合物类。结果确定了13种特征硫化合物。质谱烃类数据和PFPD硫化合物数据稳定,RSD％值分别≤0．75和≤1．29。结论该方法能对各种纵火现场助燃剂微量燃烧残留物进行有效鉴别。     

Tenax GR吸附解析技术在火场汽油残留物提取检验中的应用研究

目的针对火灾现场常规提取检验方法操作复杂、容易导致汽油残留物有效成分丢失等问题,研究建立采用Tenax GR吸附解析技术简便、高效提取检验汽油残留物的方法。方法将Tenax GR吸附管放入相关检材中,密封后在60℃烘箱中加热1h,经热脱附仪解析后使用气质联用仪分析。结果Tenax GR吸附解析技术可以检验汽油残留物中特征组分,主要包括甲苯、二甲基苯、三甲基苯、四甲基苯、萘、甲基萘及茚满类化合物。该技术的检测限为0.25pL/mL,同时放入6根吸附管做稳定性实验,其相对标准偏差(RSD)为2.43%。该技术进行7、15、30、60、90d等不同阶段的保存实验,其相对偏差分别为6.3%、14.4%、8.7%、18.3%、11.6%。结论该技术操作方便、灵敏度高、稳定性好,适用于火灾现场中汽油残留物的提取检验。     

聚乙烯塑料制品燃烧残留物对柴油分析鉴定的影响

本文以聚乙烯（PE）塑料制品——保鲜膜和聚乙烯原料为研究对象，探究二者对纵火现场助燃剂柴油分析鉴定的影响。利用固相微萃取–气相色谱–质谱法（SPME-GC-MS）对本体、未完全燃烧、完全燃烧至自燃熄灭三种不同燃烧状态下的样品与柴油的特征谱图进行对比分析。通过聚乙烯原料和PE保鲜膜本体进行对比分析发现，二者所含主要成分基本相同，PE保鲜膜中含有的个别组分在聚乙烯原料中并未检测到，主要是由于PE保鲜膜在生产过程中加入了一些添加剂所致。未完全燃烧保鲜膜对柴油分析影响最大，当m/z=85、178、192、183时，二者含有相同的成分且分布规律也基本相同，但当提取离子m/z=83时，未完全燃烧保鲜膜样品中不含有与柴油相同的环烷烃。应用SPME-GC-MS技术可以将未完全燃烧保鲜膜与柴油区分开，该方法灵敏度高，分析速度快，适用于火场中助燃剂的分析。     

LC-ESI-MS/MS法分析爆炸尘土中的硝化甘油

目的建立了高效液相色谱-质谱/质谱法（LC-ESI-MS/MS）测定尘土中的硝化甘油（NG）的方法,为日后测定爆炸残留物中的NG奠定基础。方法采用液液提取的方式提取样品,考察了前处理条件、色谱条件及质谱参数,最终确定实验方法。结果选择了最佳液相色谱质谱分析方法：固定相为SB C18（4.6×150 mm,5μm）,甲醇—0.05 mmol氯化铵做流动相,甲醇作提取溶剂;该方法在0.25～10 ng/g范围内呈良好线性,相关系数为0.9990;定量下限为0.25 ng/g;加标回收率为90.4%～95.2%。结论本方法操作简单,提取方便,有效避免了尘土复杂基质的干扰,结果准确可靠,灵敏度高,满足对爆炸残留物中硝化甘油的检测要求。     

海洛因毒品中残留有机溶剂的检测方法与结果分析

目的建立固体海洛因毒品中残留有机溶剂的顶空-气相色谱和顶空-气相色谱-质谱联用检测方法。方法采用干法和湿法处理42份样品,密封后90℃加热振荡20min,抽取顶空气体用气相色谱法（DB-WAX毛细柱,30m×0.25mm,0.25μm）和气相色谱-质谱联用法（HP-5MS毛细柱,30m×0.25mm,0.25μm）检测,以已知17种有机溶剂外标法定性。在样品中加水后检测,根据峰高估算5种共有成分的含量。结果在42份海洛因毒品中检出乙酸、乙醚、乙醇、乙酸乙酯、乙醛、三氯甲烷等12种有机溶剂成分,5种主要共有成分相对含量有差别。结论本研究建立的检测方法快速、简便,定性可靠,可用于固体海洛因毒品的来源与批次分析。     

GC/MS/MS时间编程在火灾现场助燃剂检测中的应用

运用Varian SATURN2000气质联用仪通过GC/MS、GC/MS/MS、时间编程 GC/MS/MS对汽油样品进行分析比对,发现利用时间编程GC/MS/MS,对检测火灾现场残留汽油效果很好,可彻底排除样品中基体的背景干扰,大大提高检测灵敏度;同时对混合助燃剂（汽油+煤油、汽油+柴油）进行了实验探索。     

Using Alkylate Components for Classifying Gasoline in Fire Debris Samples

The characteristic that discriminates gasoline from other ignitable liquids is that it contains high‐octane blending components. This study elaborates on the idea that the presence of gasoline in fire debris samples should be based on the detection of known high‐octane blending components. The potential of the high‐octane blending component alkylate as a characteristic feature for gasoline detection and identification in fire debris samples is explored. We have devised characteristic features for the detection of alkylate and verified the presence of alkylate in a large collection of gasoline samples from petrol stations in the Netherlands. Alkylate was detected in the vast majority of the samples. It is demonstrated that alkylate can be detected in fire debris samples that contain traces of gasoline by means of routine GC‐MS methods. Detection of alkylate, alongside other gasoline blend components, results in a more solid foundation for gasoline detection and identification in fire debris samples.     

A solid-phase microextraction method for the detection of ignitable liquids in fire debris

A solid-phase microextraction (SPME) procedure involving direct contact between the SPME fibers and the solid matrix and subsequent gas chromatography/mass spectrometric analysis for the detection of accelerants in fire debris is described. The extraction performances of six fibers (100 mum polydimethylsiloxane, 65 mum polydimethylsiloxane-divinylbenzene, 85 mum polyacrylate, 85 mum carboxen-polydimethylsiloxane, 70 mum Carbowax-divinylbenzene, and 50/30 mum divinylbenzene-Carboxen-polydimethylsiloxane) were investigated by directly immersing the fibers into gasoline, kerosene, and diesel fuel. For simulated fire debris, in the direct contact extraction method, the SPME fiber was kept in contact with the fire debris matrix during extraction by penetrating plastic bags wrapping the sample. This method gave comparable results to the headspace SPME method in the extraction of gasoline and kerosene, and gave an improved recovery of low-volatile components in the extraction of diesel fuel from fire debris. The results demonstrate that this procedure is suitable as a simple and rapid screening method for detecting ignitable liquids in fire debris packed in plastic bags.     

Evaluation of a Headspace Solid‐Phase Microextraction Method for the Analysis of Ignitable Liquids in Fire Debris

The chemical analysis of fire debris represents a crucial part in fire investigations to determine the cause of a fire. A headspace solid‐phase microextraction (HS‐SPME) procedure for the detection of ignitable liquids in fire debris using a fiber coated with a mixture of three different sorbent materials (Divinylbenzene/Carboxen/Polydimethylsiloxane, DVB/CAR/PDMS) is described. Gasoline and diesel fuel were spiked upon a preburnt matrix (wood charcoal), extracted and concentrated with HS‐SPME and then analyzed with gas chromatography/mass spectrometry (GC/MS). The experimental conditions—extraction temperature, incubation and exposure time—were optimized. To assess the applicability of the method, fire debris samples were prepared in the smoke density chamber (SDC) and a controlled‐atmosphere cone calorimeter. The developed methods were successfully applied to burnt particleboard and carpet samples. The results demonstrate that the procedure that has been developed here is suitable for detecting these ignitable liquids in highly burnt debris.     

Comparison of gasolines using gas chromatography-mass spectrometry and target ion response

Gas chromatography-mass spectrometry was used to compare gasoline samples obtained from different sources based on the difference in amounts of certain components found in the headspace of gasoline using target response data. Many suspected arson cases involve comparing an ignitable liquid extracted from fire debris to a liquid found in a suspect's possession to determine if they could have had a common source. Various component ratios are proposed for determining if an unevaporated gasoline sample could have originated from the same source as an evaporated gasoline extracted from fire debris. Fifty and 75% evaporated gasoline samples were both found to contain similar ratios of certain components when compared with its unevaporated source gasoline. The results of the comparisons in this study demonstrate that for cases involving gasoline that has been evaporated up to 50% and extracted from pine, it is possible to eliminate comparison samples as originating from the same source. The results of the 75% comparisons suggest it may be possible to apply the same type of comparison to cases involving 75% evaporated gasoline.     

Progress Toward the Determination of Correct Classification Rates in Fire Debris Analysis II: Utilizing Soft Independent Modeling of Class Analogy (SIMCA)

A multistep classification scheme was used to detect and classify ignitable liquid residues in fire debris into the classes defined by the ASTM E1618‐10 standard method. The total ion spectra (TIS) of the samples were classified by soft independent modeling of class analogy (SIMCA) with cross‐validation and tested on fire debris. For detection of ignitable liquid residue, the true‐positive rate was 94.2% for cross‐validation and 79.1% for fire debris, with false‐positive rates of 5.1% and 8.9%, respectively. Evaluation of SIMCA classifications for fire debris relative to a reviewer's examination led to an increase in the true‐positive rate to 95.1%; however, the false‐positive rate also increased to 15.0%. The correct classification rates for assigning ignitable liquid residues into ASTM E1618‐10 classes were generally in the range of 80–90%, with the exception of gasoline samples, which were incorrectly classified as aromatic solvents following evaporative weathering in fire debris.