Primer residue analysis of ammunition of Indian origin by neutron activation analysis

The primer residues of ammunition manufactured in India have been analysed by neutron activation analysis (NAA). Since NAA is rather insensitive for lead, attention was confined to the elements antimony, barium, copper and mercury. The element/element combinations detected in significant amounts were (Sb), (Ba, Hg), (Ba, Cu, Sb), (Cu, Hg, Sb) and (Hg, Sb). The present study reveals the presence of Hg from mercury fulminate in priming compositions long discontinued in most ammunition of foreign origin. The presence of Hg can be advantageous in certain situations where the matrix on which the residue is deposited contains high levels of antimony such as clothing made of synthetic fibres. Caution is also required in interpreting the Cu values as being solely due to a jacketed projectile.     

Comparison analysis of illicit cocaine samples.

A rapid method for comparison analysis of illicit cocaine samples has been developed. The raw data are obtained by capillary gas chromatography using a nitrogen-phosphorus detector. The area ratios of four alkaloids (tropacocaine, norcocaine, cis-cinnamoylcocaine, and trans-cinnamoylcocaine) to cocaine are calculated for each sample. These ratios are compiled in a computer database which allows easy comparison of samples and makes possible reliable conclusions regarding their commonality of origin.     

Analysis of Indian blue ballpoint pen inks tagged with rare-earth thenoyltrifluoroacetonates by inductively coupled plasma-mass spectrometry and instrumental neutron activation analysis

Characterization and assessment of inks on sensitive documents for absolute/relative age determination is the challenging forensic problem in spite of practical difficulties. Tagging of ballpoint pen ink with suitable taggant(s) is a unique method to come out with definitive inferences on the detection of forgery in documents written with ballpoint pens. Selection of a proper taggant primarily depends on sensitivity of analytical determination and their absence in normal varieties of ink used for document writing. Rare-earth elements, from all technical considerations can be potential taggant(s) for inks. To ensure more compatibility with ink, 13 rare-earth thenoyltrifluoroacetonate chelates were prepared and characterized. The ballpoint pen inks were tagged with rare-earth thenoyltrifluoroacetonate chelates individually at about 1-100 ppm level depending on sensitivity of element under suitable optimized experimental conditions and instrumental sensitivity. Aliquots of such tagged ink having varying amounts of taggants were analyzed by ICP-MS and INAA. Satisfactory recoveries and a good linear relationship of intensity (signal) against concentrations/amounts were observed. Under the optimized experimental conditions, the detection limits were worked out. This study of tagging metal ions in combination with ICP-MS and NAA as an analytical tool can allow to draw various combination options based on different rare-earth chelates as suitable materials for tagging of ballpoint pen inks for absolute/relative age determination to aid in document related crime examination. The advantages and limitations of proposed analytical techniques are discussed.     

Bullet identification: a case of a fatal hunting accident resolved by comparison of lead shot using instrumental neutron activation analysis.

Bullet identification by chemical analysis often provides a powerful clue in forensic science. A case is reported in which a hunting accident was resolved by using instrumental neutron activation analysis (INAA) for direct comparison of the trace element content in lead shot. Different preparation batches of lead shot appear to have a high within-group composition homogeneity, and good differentiation is achieved between different batches. Determination of the nickel and antimony content on a bush branch demonstrated that the branch had been perforated by one of the shot pellets, and this helped the detectives in reconstruction of the crime scene.     

Sourcing Brazilian marijuana by applying IRMS analysis to seized samples

The stable carbon and nitrogen isotopic ratios were measured in marijuana samples (Cannabis sativa L.) seized by the law enforcement officers in the three Brazilian production sites: Pernambuco and Bahia (the country's Northeast known as Marijuana Polygon), Pará (North or Amazon region) and Mato Grosso do Sul (Midwest). These regions are regarded as different with respect to climate and water availability, factors which impact upon the isotope fractionations of these elements within plants. It was possible to differentiate samples from the dry regions (Marijuana Polygon) from those from Mato Grosso do Sul and Pará, that present heavier rainfall. The results were in agreement with the climatic conditions of the suspected regions of origin and this demonstrates that seized samples can be used to identify the isotopic signatures of marijuana from the main producing regions in Brazil.     

Comparative analysis of illicit heroin samples

The comparative analysis of street heroin samples is still an object of scientific discussion. A combination of a wide range of analytical techniques is necessary to obtain a valid amount of information about the sample composition, and it is impossible to define an unique analytical approach. We suggest a complete analytical sequence based on analysis of volatile compounds, opiates, diluents, adulterants and metals, by head space gas chromatography (HS/GC), gas chromatography mass spectrometry (GC/MS), thin layer chromatography (TLC), high pressure liquid chromatography (HPLC) and atomic absorption (AA) using a sample amount as low as 50-100 mg. The outlined procedure can be successfully applied to routine work, thus obtaining suitable information about a sample's chemical composition. This helps to attribute or exclude common sources of separate specimens. Results obtained on 33 street heroin samples confiscated in the metropolitan area of Rome are listed.     

固相萃取、气相色谱法测定拟除虫菊酯农药

研究了水样中的微量拟除虫菊酯农药用固相萃取(C18)、GC/ECD法进行测定结果表明,250ml空白水中添加2μg混标拟除虫菊酯农药,氯氰菊酯、氰戊菊酯和溴氰菊酯回收率分别为37.7%、94.4%和78.2%.该方法简单快速、效果好,已成功应用于实际办案中.     

全血中扎来普隆两种萃取方法的比较

目的建立血样中扎来普隆的液液萃取和固相萃取方法。方法液液萃取方法是在碱性条件下用二氯甲烷提取。固相萃取是采用OasisHLB固相萃取柱提取,萃取液均用GC/NPD检验,并对其进行比较。结果血样中扎来普隆固相萃取平均回收率达89%以上,液液萃取平均回收率为84%,GC/NPD最低检出限为2×10-2μg.mL-1。结论两种方法均能满足实际检案的需求,而固相萃取方法在减少仪器损耗和内源性杂质干扰方面具有较大的优势。