Quantification and aging of the post-blast residue of TNT landmines

Post-blast residues are potential interferents to chemical detection of landmines. To assess the potential problem related to 2,4,6-trinitrotoluene (TNT), its post-blast residue was identified and quantified. In the first part of this study laboratory-scale samples of TNT (2 g) were detonated in a small-scale explosivity device (SSED) to evaluate the explosive power and collect post-blast residue for chemical analysis. Initiator size was large relative to the TNT charge; thus, issues arose regarding choice of initiator, residue from the initiator, and afterburning of TNT. The second part of this study detonated 75 to 150 g of military-grade TNT (typical of antipersonnel mines) in 55-gal barrels containing various witness materials (metal plates, sand, barrel walls, the atmosphere). The witness materials were analyzed for explosive residue. In a third set of tests, 75-g samples of TNT were detonated over soil (from Fort Leonard Wood or Sandia National Laboratory) in an indoor firing chamber (100 by 4.6 by 2.7 m high). Targeted in these studies were TNT and four explosive-related compounds (ERC): 2,4-dinitrotoluene (DNT), 1,3-dinitrobenzene (DNB), 2- and 4-aminodinitrotoluene (2-ADNT and 4-ADNT). The latter two are microbial degradation products of TNT. Post-blast residue was allowed to age in the soils as a function of moisture contents (5 and 10%) in order to quantify the rate of degradation of the principal residues (TNT, DNT, and DNB) and formation of the TNT microbial degradation products (2-ADNT and 4-ADNT). The major distinction between landmine leakage and post-blast residue was not the identity of the species but relative ratios of amounts. In landmine leakage the DNT/TNT ratio was usually greater than 1. In post-blast residue it was on the order of 1 to 1/100th of a percent, and the total amount of pre-blast residue (landmine leakage) was a factor of 1/100 to 1/1000 less than post-blast. In addition, landmine leakage resulted in low DNT/ADNT ratios, usually less than 1, whereas pre-blast residues started with ratios above 20. Because with time DNT decreased and ADNT increased, over a month the ratio decreased by a factor of 2. The rate of TNT degradation in soil observed in this study was much slower than that reported when initial concentrations of TNT were lower. Degradation rates yielded half-lives of 40 and 100 days for 2,4-DNT and TNT, respectively.     

Comparison of bulk and compound-specific δ13C isotope ratio analyses for the discrimination between cannabis samples

Five marijuana samples were compared using bulk isotope analysis compound-specific isotope ratio analysis of the extracted cannabinoids. Owing to the age of our cannabis samples, four of the five samples were compared using the isotope ratios of cannabinol (CBN), a stable degradation product of Δ(9)-tetrahydrocannabinol (THC). Bulk δ(13)C isotope analysis discriminated between all five samples at the 95% confidence level. Compound-specific δ(13)C isotope analysis could not distinguish between one pair of the five samples at the 95% confidence level. All the measured cannabinoids showed significant depletion in (13)C relative to bulk isotope values; the isotope ratios for THC, CBN, and cannabidiol were on average 1.6‰, 1.7‰, and 2.2‰ more negative than the bulk values, respectively. A more detailed investigation needs to be conducted to assess the degree fractionation between the different cannabinoids, especially after aging.     

Sourcing explosives: A multi-isotope approach

Although explosives are easily identified with current instrumental techniques, it is generally impossible to distinguish between sources of the same substance. To alleviate this difficulty, we present a multi-stable isotope (δ¹³C, δ¹⁵N, δ¹⁸O, δD) approach for appraising the possibility of discriminating explosives. The results from 30 distinct PETN, TNT and ANFO samples show that the different families of explosives are clearly differentiated by both their specific isotope signatures and their combination with corresponding element concentrations. Coupling two or more of the studied isotope systematics yields an even more precise differentiation on the basis of their raw-material origin and/or manufacturing process.     

Simultaneous identification and δ¹³C classification of drugs using GC with concurrent single quadrupole and isotope ratio mass spectrometers

In this study, δ13C values of six cocaine samples were identified and classified using a single quadrupole mass spectrometer and an isotope ratio mass spectrometry (IRMS) as simultaneous gas chromatography detectors. Our instrument modification is simple to use and is useful (i) when the sample is of limited size or can only be injected once, (ii) to help identify peaks in a complicated IRMS chromatogram, and (iii) to help differentiate very simple systems when impurity profiling is not possible. The EI-MS confirmed the identity of cocaine in each sample. The IRMS data distinguished 12 of the 15 possible pair-wise comparisons at the 95% CL. Three samples could not be differentiated by their δ13C ratios for cocaine. ANOVA demonstrated that the measurement variance was consistently larger than the sample variance. As the δ13C values clearly show, this technique enables the exclusion of a potential common source even when two samples have otherwise identical chemical and physical properties.     

Forensic utility of carbon isotope ratio variations in PVC tape backings

Forensic interest in adhesive tapes with polyvinyl chloride (PVC) backings (electrical tape) derives from their use in a variety of illicit activities. Due to the range of physical characteristics, chemical compositions, and homogeneity within a single roll of tape, traditional microscopic and chemical analyses can offer a high degree of discrimination between tapes, permitting the assessment of potential associations between evidentiary tape samples. The carbon isotope ratios of tapes could provide additional discrimination among tape samples. To evaluate whether carbon isotope ratios may be able to increase discrimination of electrical tapes, particularly with regards to different rolls of tape of the same product, we assessed the δ(13)C values of backings from 87 rolls of PVC-based black electrical tape (~20 brands, >60 products) Prior to analysis, adhesives were removed to prevent contamination by adhering debris, and plasticizers were extracted because of concern over their potential mobility. This result is consistent with each of these tapes having approximately the same plasticizer δ(13)C value and proportion of carbon in these plasticizers. The δ(13)C values of the 87 PVC tape backings ranged between -23.5 and -41.3 (‰, V-PDB), with negligible carbon isotopic variation within single rolls of tape, yet large variations among tape brands and tape products. Within this tape population, carbon isotope ratios permitted an average exclusion power of 93.7%, using a window of +/-0.3‰; the combination of carbon isotope ratio measurement with additional chemical and physical analyses raises the discrimination power to over 98.9%, with only 41 out of a possible 3741 pairs of tape samples being indistinguishable. There was a linear relationship between the δ(13)C value of tape backings and the change in δ(13)C value with the extraction of plasticizers. Analyses of pre- and post-blast tape sample pairs show that carbon isotope signatures are within 0.3‰ of pre-blast values, indicating that carbon isotope values are largely preserved during an explosion.     

Carbon and Nitrogen Stable Isotope Analyses of Ephedra Plant and Ephedrine Samples and Their Application For Methamphetamine Profiling

In this study, stable isotope ratio analysis was used to track the precursor information of methamphetamine. The δ¹³C and δ¹⁵N values of 30 nature ephedra plants, 12 synthetic ephedrine/pseudoephedrine (ephedrine), 14 natural ephedrine, and 987 seized methamphetamine samples were measured and compared. Due to different weather and earth conditions, the δ¹³C and δ¹⁵N values of ephedra plants grown in the east and the west of Inner Mongolia showed great difference. The δ¹⁵N values of ephedra plants were consistent with related ephedrine extracted from them. Moreover, the criteria to infer the synthetic origin of ephedrine were set up after the analysis of natural and synthetic ephedrine samples. Finally, the precursor origins of 949 seized methamphetamine samples synthesized by Emde and Nagai method were tentatively inferred. Influenced by different preprecursors, the δ¹³C values of seized methamphetamine samples that synthesized from P2P also showed great difference, and this result is consistent with the reported data.     

LC-MS-MS analysis of buprenorphine and norbuprenorphine in whole blood from suspected drug users

A liquid chromatography tandem mass spectrometry method is described for the analysis of buprenorphine and norbuprenorphine in whole blood. Linearity was achieved between 0.2-5 ng/g for buprenorphine and 0.5-5 ng/g for norbuprenorphine. Stability studies on spiked whole blood and an authentic sample showed no degradation of buprenorphine- and norbuprenorphine-glucuronide to their respective aglycones. Buprenorphine and norbuprenorphine showed some degradation when stored at 4°C for three weeks, but was stable when stored at -20°C for 4 weeks. The method was applied to forensic cases of driving under the influence of drugs (DUID) and petty drug offences (PDO) during 2007-2009. Out of 2459 cases analyzed, 322 were positive for both buprenorphine and norbuprenorphine (13%), 219 for buprenorphine only (9%), and 12 for norbuprenorphine only (0.5%). The mean and median concentrations (N=322) were 1.7 and 1.0 ng/g, respectively, for buprenorphine and norbuprenorphine. The mean and median norbuprenorphine/buprenorphine ratios were 1.5 and 1.1, respectively. There was no significant difference in concentration ratios for DUID and PDO cases (p>0.05). We conclude that the described method for analysis of buprenorphine and norbuprenorphine in whole blood could be used to investigate use or misuse of buprenorphine but that many of the cases presented with very low concentrations of buprenorphine. We also conclude that analysis should be performed within two weeks unless samples are stored frozen prior to analysis.     

Stable isotope analysis of human hair and nail samples: the effects of storage on samples

When submitting samples for analysis, maintaining sample integrity is essential. Appropriate packaging must be used to prevent damage, contamination or loss of sample. This is particularly important for stable isotope analysis by isotope ratio mass spectrometry as this technique is capable of detecting subtle differences in isotopic composition with great precision. In a novel study, scalp hair and fingernail samples were placed in five different types of packaging, routinely used in forensic laboratories and stored for 6 weeks and 6 months. Samples were subsequently cleaned and submitted for (13)C/(12)C, (15)N/(14)N, (2)H/(1)H and (18)O/(16)O analysis. Results from (13)C analysis indicate that type of packaging can cause slight changes in (13)C abundance over time. Differences were noted in the (15)N isotope signatures of both hair and nail samples after 6-week storage, but not after 6 months. This apparent discrepancy could be a result of the packaging not being properly sealed in the 6 weeks study. Fewer differences were noted when analyzing samples for (2)H and (18)O abundance.     

Selective colorimetric determination of TNT partitioned between an alkaline solution and a strongly basic Dowex 1-X8 anion exchanger

The Meisenheimer anions formed from TNT in KOH solutions in alcohol or acetone were used in screening tests for TNT among possible nitro-explosives. The same reaction was used for the spectrophotometric assay of TNT in soil by CRREL (Cold Regions Research & Engineering Laboratory of the U.S. Army) method, also known as Jenkins' method, but the color stability was too dependent on the solution composition and the water tolerance was low, necessitating complete drying of soil samples (which may cause partial analyte decomposition) prior to analysis. This study reports the development of a colorimetric method based on the solid phase extraction (SPE) of the Meisenheimer anion formed from TNT and aqueous NaOH into a strongly basic anion exchange resin Dowex 1-X8 (OH(-) form). The orange-red color that developed both in the solid resin and solution phases was persistent for at least 1h. The resin was let to swell in alcohol, washed first with 1M aqueous NaOH, and then with H(2)O before use. To 5 mL of 4-400 ppm TNT solutions in 1:1 (v/v) acetone-water, 0.5 mL of 5% NaOH was added, diluted to 50 mL with 1:1 acetone-water, and the resulting solutions (containing the orange-red Meisenheimer anion of TNT) were agitated at room temperature with 0.9 g resin for < or =50 min. TNT exhibited a reasonably constant distribution coefficient between the resin and aqueous phases. The absorbance of the filtered solutions was measured against a reagent blank at 500nm. The TNT-loaded resins were regenerated with 1M HCl containing sodium sulfite. The calibration line of filtrate absorbance versus analytical concentration was linear over two orders of magnitude between 0.4 and 40 ppm TNT in final solution. Unlike Jenkins' method, the method was tolerant to 100-fold (by mass) of common soil anions like sulfate, nitrate, and chloride. The basic advantages of the developed colorimetric method over the similar CRREL/Jenkins' method may be summarized as color stability, water and common ion tolerance, lowering of the LOD, and widening of the linear range. As opposed to Jenkins' method, the charge-transfer bands characteristic to colorimetric detection were not obscured by the presence of water. The method is suitable for on-site applications, because the color developed in heterogenous solution was stabilized, and the method can be easily practiced with a portable colorimeter to large numbers of samples.     

Discrimination of arsenous acids with comparison of trace elements contained by using synchrotron X-ray fluorescence spectrometry

In the poisonous incident case occurred in Japan, clarification of the identity between seized poisons and retrieved from crime scene is strictly required from the court. In this case, arsenous acid was used as a poisonous material and, seized one from suspect's house was only twenty particles. The synchrotron X-ray fluorescence spectrometry by comparing the intensity ratios of L(alpha) line of four heavy metal, such as Bi, Sn, Sb, Se to K(beta) line of As was performed to overcome this problem. In this paper, the evaluation of this new method using 13 authentic arsenous acid samples, 4 of 13 were refined by Chinese method, 7 of 13 were refined by Japanese method (Sumitomo mining Co. Ltd. method), 2 of 13 were refined by German and Swiss method. As a result, by the comparison of the ratios of these four elements to As, these 13 samples were clearly classified to three products classes produced by different refining methods.     

Application of LC−QTOF/MS for the validation and determination of organic explosive residues on Ionscan® swabs

The identification and confirmation of trace explosive residues along with potential precursors and degradation products require a comprehensive laboratory analysis procedure. This study presents the determination of organic explosives consisting of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), 2,4,6-trinitrotoluene (TNT), 2,4,6,N-tetranitro-N-methylaniline (Tetryl), 1,3,5-trinitrobenzene (1,3,5-TNB) and pentaerythritol tetranitrate (PETN) by a high-resolution liquid chromatography quadrupole time-of-flight mass spectrometry (LC−QTOF/MS). The qualitative information including retention time, collision energy, precursor ions, and characteristic fragmentation pattern of each explosive were collected using an atmospheric pressure chemical ionization (APCI) in negative ion mode. The separation efficiency among five compounds was greatly achieved in this study. Four real explosive samples consisting of TNT, RDX, PETN and Tetryl and 12 Ionscan® quality control swabs from the Royal Thai Army were also tested to validate and verify the viability of the GC–MS method used to validate results from an Ionscan® system. The results showed that LC−QTOF/MS is a powerful technique for the identification and confirmation of thermally unstable organic explosives on Ionscan® swabs compared to a conventional GC−MS technique.     

Accumulation of explosives in hair--part II: factors affecting sorption

This study examines the sorption of eight explosives (2,4,6-trinitrotoluene [TNT]; pentaerythritol tetranitrate [PETN]; hexahydro-1,3,5-trinitro-s-triazine [RDX]; diacetone diperoxide [DADP]; triacetone triperoxide [TATP]; ethylene glycol [EGDN], nitroglycerin [NG]; and 2,4-dinitrotoluene [DNT]) to human hair. The study uses only cut hair, which is exposed to explosive vapor. The vapor transfer studies reported herein indicated that hair did not reach saturation even after 2.5 years of exposure to TNT. While previous studies showed black hair sorbed more explosive than blond or brown, this study reports that red hair sorption is similar to black, while grey hairs, exposed along with black hair from the same individual, sorbed significantly less explosive than the same individual's black hairs. In a study using only black hair, a slight racial bias was observed with sorption greater for Mongoloid hair as compared to Caucasian or Negroid. Only for Mongoloid hairs were enough samples studied to examine for a gender bias, but one was not observed. There was much variability in results in all categories (hair color, race, and gender) that trends were established only in general terms. Hair at different ages was tested for a few individuals. Detailed studies focused on the sorption of TATP and TNT as these appear to be sorbed most differently-TATP mainly on the hair surface and TNT both on the surface and in the cortex. The uptake of high vapor pressure explosives (e.g., TATP) and moderate vapor pressure explosives (e.g., TNT) by hair was rapid and could be detected within about 1 h of exposure. Both explosives were readily sorbed by pure melanin.     

尿中氯胺酮及其代谢物盘鉴和GC/MS/SIM测定

目的 研究尿中氯胺酮(KET)及其代谢物去甲基氯胺酮(NKET)的盘鉴(Disk SPE)。方法 用含有化学键合C18和强酸型强阳离子交换(SCX)基团的萃取柱SPEC.C18 AR/MP3萃取,加入萃取柱前的尿样用0.1mol/L磷酸盐缓冲溶液(pH 6)稀释,洗脱溶剂为含2％(v/v)氨水的乙酸乙酯;以2,4,6-三硝基甲苯(TNT)为色谱内标,GC/MS/SIM检测。结果 在加标量为0.5μg/mL、2μg/mL和6μg/mL的控制尿样中,KET和NKET的平均回收率分别为91.5％和79.9％,6次测定的RSD均为8.7％;线性范围0.02-8μg/mL,线性相关系数分别为0.9819和0.9964;检出限(S/N=3)分别为6ng/mL和4ng/mL;总离子色谱图背景低,杂质少。同一根萃取柱重复使用8次以上未见性能下降;嫌疑尿样中检出KET和/或NKET,和常规的液液萃取结果相符。结论 该方法适用于尿中KET和NKET的同时测定。     

Isotope ratio mass spectrometry as a tool for forensic investigation (examples from recent studies).

The versatility of isotope ratio mass spectrometry is demonstrated by reference to diverse case studies. Variations in the natural isotopic composition of non-biological, organic materials are compared as a means by which samples may be associated or discriminated. These techniques may be used to augment or compliment conventional forensic methodologies. delta13C analysis was used to demonstrate that different masking tape had been recovered in two, apparently similar cases, involving the smuggling of money. Visually similar ecstasy tablets were compared by consideration of the delta13C and delta15N composition of MDMA extracted from the tablets. Although only a limited number of tablets were analysed, the isotopic similarity between two different seizures was sufficient to induce a guilty plea from a person suspected of possessing both. A combination of delta2H, delta13C, delta15N and delta18O together with GC-MS analyses were applied to small samples of seized heroin. Although GC-MS analysis indicated differences between the chemical composition of two of the heroin samples, isotopic analysis suggested similarities, which were confirmed by further delta2H, delta13C and delta18O isotopic analysis of the clingfilm in which the samples were wrapped.     

Case of Fatal Starvation: Can Stable Isotope Analysis Serve to Support Morphological Diagnosis and Approximate the Length of Starvation?

The diagnosis of death as a result of starvation is established on anthropological measurements, visual appearance of the deceased on external and internal examination, microscopic analysis, laboratory testing, and exclusion of other causes of death. Herein, we present our findings on a case of 95‐year‐old man who died of starvation. After the diagnosis of starvation was established by traditional forensic medicine methods, we have conducted retrospective segmental analysis of stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios in hair sample. This method reveals periods of starvation through decrease in δ¹³C and increase in δ¹⁵N along the strand of hair. Our analysis revealed the decrease of 0.6 ‰ in δ¹³C during the last 10–12 weeks prior to death, similar as reported in other investigations. Also, a decrease of 0.7 ‰ in δ¹⁵N during the last 8–10 weeks prior to death was determined that was different than observed in previous studies.     

不同分型方法的STR分型差异

目的调查不同的STR分型系统之间分型的一致性。方法 10 0例不同个体的DNA样本分别用单位点聚丙烯酰胺凝胶银染法和PowerPlex16System试剂盒对 13个法医学常用STR位点进行基因分型 ,并比较两种不同分型系统间的分型结果。结果 1例样本在D8S1179位点出现了分型不一致的结果 :银染法的基因型为 12 / 14 ,而用PowerPlex16System试剂盒的分型则为 12 / 15。结论不同的STR分型系统可导致不同的基因分型     

Are Perceptions of Organizational Justice Universal? An Exploration of Measurement Invariance Across Thirteen Cultures

Previous research examined whether justice effects are comparable, focusing on quantitative differences in justice effects. This study examines whether justice perceptions are structured similarly or whether they are qualitatively different across working populations from 13 nations. Confirmatory factor analysis and multi-group analysis show that Colquitt??s (J Appl Psychol 86:386?C400, 2001) four-dimensional model of justice works well across these samples. However, factor intercorrelations and reliabilities are found to systematically vary between cultural samples. Perceptions of justice are more highly intercorrelated in power distant and collectivistic samples, in line with extensions of the relational model of authority. Score reliabilities were lower in collectivistic settings.     

Comparative analysis of 1-phenyl-2-propanone (P2P), an amphetamine-type stimulant precursor, using stable isotope ratio mass spectrometry: Presented in part as a poster at the 2nd meeting of the Joint European Stable Isotope User Meeting (JESIUM), Giens, France, September 2008

The isotope ratios of amphetamine type stimulants (ATS) depend as well on the precursor as the synthetic pathway. For clandestine production of amphetamine and methamphetamine, 1-phenyl-2-propanone (P2P, benzylmethylketone) is a commonly used precursor.Our aim was to determine the variation of the isotope ratios within precursor samples of one manufacturer and to compare seized samples of unknown sources to these values. δ¹³C_V-PDB, δ²H_V-SMOW and δ¹⁸O_V-SMOW isotope ratios were determined using elemental analysis (EA) and gas chromatography (GC) coupled to an isotope ratio mass spectrometer (IRMS). The comparison of all seized samples to the data of the samples of one manufacturer revealed considerable differences. The results show that IRMS provides a high potential in differentiating between precursors from different manufacturers for the clandestine production of ATS and identifying corresponding sources.     

不同温度下血样中毒鼠强的稳定性

目的探讨不同保存温度下血样中毒鼠强的稳定性。方法配制毒鼠强质量浓度为0.5μg/mL的血液样品,分别置于45℃、25℃和4℃环境中保存,在配制当天及存放3、12、18和39d用气相色谱-质谱联用法测定其质量浓度,运用SPSS统计软件对结果进行统计分析。结果45℃、25℃下血样存放3d毒鼠强质量浓度基本不变,存放4～12d毒鼠强质量浓度有明显下降,存放12d后毒鼠强质量浓度缓慢下降;4℃下血样存放12d毒鼠强质量浓度基本不变,存放13～18d毒鼠强质量浓度有明显下降,存放18d后毒鼠强样品质量浓度缓慢下降。结论血样中毒鼠强质量浓度在最初的3d内稳定,此后浓度下降。保存温度对血样中毒鼠强质量浓度有影响。     

Cyanide distribution in five fatal cyanide poisonings and the effect of storage conditions on cyanide concentration in tissue

The cyanide distribution in five fatal cyanide poisonings was analyzed by the pyridine-pyrazolone method using a Conway diffusion cell. In order to study the effect of storage conditions on cyanide concentration in tissue samples, the cyanide concentrations were first measured immediately after collection of the samples at autopsy, then measured again after storage in a refrigerator (4 degrees C) or in a freezer (-20 degrees C) for periods ranging from 1 day to 3 weeks. Concentrations in all but three of the blood samples stored at 4 degrees C or -20 degrees C increased, with concentration ratios based on measurement made before and after storage ranging from 0.71 to 1.46. The concentrations in the liver, kidney, and brain samples either increased or decreased, with ratios of from 0.2 to 8.8. The concentrations in the stomach contents samples decreased rapidly at 4 degrees C, but hardly changed at all at -20 degrees C.