Gunshot residue testing in suicides: Part I: Analysis by scanning electron microscopy with energy-dispersive X-ray

Several different methods can be employed to test for gunshot residue (GSR) on a deceased person's hands, including scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Each of these techniques has been extensively studied, especially on living individuals. The current studies (Part I and Part II) were designed to compare the use and utility of the different GSR testing techniques in a medical examiner setting. In Part I, the hands of deceased persons who died from undisputed suicidal handgun wounds were tested for GSR by SEM-EDX over a 4-year period. A total of 116 cases were studied and analyzed for caliber of weapon, proximity of wound, and results of GSR testing, including spatial deposition upon the hands. It was found that in only 50% of cases with a known self-inflicted gunshot wound was SEM-EDX positive for at least 1 specific particle for GSR. In 18% of the cases there was a discernible pattern (spatial distribution) of the particles on the hand such that the manner in which the weapon was held could be determined. Since only 50% of cases where the person is known to have fired a weapon immediately prior to death were positive for GSR by SEM-EDX, this test should not be relied upon to determine whether a deceased individual has discharged a firearm. Furthermore, in only 18% of cases was a discernible pattern present indicating how the firearm was held. The low sensitivity, along with the low percentage of cases with a discernible pattern, limits the usefulness of GSR test results by SEM-EDX in differentiating self-inflicted from non-self-inflicted wounds.     

Forensic discrimination of match heads by elemental analysis with inductively coupled plasma-atomic emission spectrometry

In arson and bombing cases, matches are often used as the ignition method. We have investigated the use of elemental analysis by inductively coupled plasma-atomic emission spectrometry to discriminate match heads used in arson cases. Six elements, magnesium, aluminum, calcium, iron, zinc, and barium, in match heads were detected after the match heads were dissolved in HNO3, and these elements were quantified in 8 wood stick matches and 5 paper stick matches by means of calibration curves prepared from standard sample solutions. Using this method, we were able to distinguish all the matches from one another both before and after combustion. The method has the potential to be very useful for resolving arson cases.     

血、尿中金属毒物的电感耦合等离子发射光谱检测方法

目的建立血和尿中的有毒金属元素快速检测方法。方法通过模拟样品,采用微波消解炉对样品进行预处理,用电感耦合等离子发射光谱仪同时对多种可疑有毒金属元素进行检测。结果血、尿样品经消解或酸稀释处理,镉、钴、铬、铜、镍等元素可检测方法平均回收率范围为75.5%～127.5%,变异系数小于16.4%结论在中毒剂量,对肝脏和肾脏组织中的可疑有毒金属元素,可以采用电感耦合等离子发射光谱仪同时进行检测。     

Analysis of gunshot residue test results in 112 suicides

The results of gunshot residue (GSR) tests in 112 suicide cases investigated by the U.S. Army Criminal Investigation Command over a ten-year period are described. Only suicide cases in which there was certainty that the victim fired a weapon were examined in an effort to reduce ambiguous results. Previous case work research by Rudzitis indicated that positive GSR test results were encountered in suicides 62% of the time using various combinations of neutron activation analysis (NAA) and atomic absorption spectrophotometry (AAS). Threshold values of 0.2-micrograms antimony and 0.3-micrograms barium (0.2-micrograms antimony and 0.5-micrograms barium after 1985) used by the U.S. Army Criminal Investigation Laboratory resulted in positive GSR results in suicide cases 38% of the time. The effects of time, location of body, handling of the body, weapon type, caliber, and condition of the hands on GSR results are examined. Case studies involving suicides by unit armorers are discussed.     

The analysis of some evidential materials by inductively coupled plasma-optical emission spectrometry

Inductively coupled plasma-optical emission spectrometry (ICP-OES) is under evaluation at the Central Research Establishment for the analysis of evidential materials. The analysis of standard reference materials has demonstrated that quantitative multi-element data can be obtained from small samples of a variety of materials. The results of some determinations carried out in support of casework investigations are reported.     

Gunshot residue in Chicago police vehicles and facilities: an empirical study

Suspects in shooting investigations in Chicago are routinely transported in department vehicles and detained in department facilities prior to gunshot residue (GSR) evidence collection. The GSR test results are used to associate the suspect with primary exposure to GSR. The potential for these vehicles and facilities being sources of secondary GSR contamination needed to be determined. A total of 201 samples were collected from randomly selected vehicles and detention facilities. The sampling collected trace materials from surfaces that suspects' hands may contact during the arrest process. These samples were examined for the presence of GSR particles using scanning electron microscopy. Upon completion of the automated analysis, those particles that met an initial GSR screening criterion were relocated and reanalyzed. The locations where GSR particles were recovered allowed us to make recommendations to the Chicago Police Department with regard to transporting and detaining these suspects. The low number of GSR particles recovered suggests that the potential for secondary contamination, although present, is relatively low.     

发射光谱分析微量油漆串并系列盗枪案

目的检验4个现场提取的残留油漆,为系列枪支被盗案件串并案提供依据。方法发射光谱分析油漆微量元素成份。结果4个现场提取的油漆微量元素成份一致,根据痕迹特征,属同一种工具所致。结论该方法经济快速、灵敏度高、用材量少,适用于微量元素分析。     

Elemental analysis of glass by laser ablation inductively coupled plasma optical emission spectrometry (LA-ICP-OES)

The elemental analysis of glass evidence has been established as a powerful discrimination tool for forensic analysts. Laser ablation inductively coupled plasma optical emission spectrometry (LA-ICP-OES) has been compared to laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) and energy dispersive micro X-ray fluorescence spectroscopy (μXRF/EDS) as competing instrumentation for the elemental analysis of glass. The development of a method for the forensic analysis of glass coupling laser ablation to ICP-OES is presented for the first time. LA-ICP-OES has demonstrated comparable analytical performance to LA-ICP-MS based on the use of the element menu, Al (Al I 396.15 nm), Ba (Ba II 455.40 nm), Ca (Ca II 315.88 nm), Fe (Fe II 238.20 nm), Li (Li I 670.78 nm), Mg (Mg I 285.21 nm), Sr (Sr II 407.77 nm), Ti (Ti II 368.51 nm), and Zr (Zr II 343.82 nm). The relevant figures of merit, such as precision, accuracy and sensitivity, are presented and compared to LA-ICP-MS. A set of 41 glass samples was used to assess the discrimination power of the LA-ICP-OES method in comparison to other elemental analysis techniques. This sample set consisted of several vehicle glass samples that originated from the same source (inside and outside windshield panes) and several glass samples that originated from different vehicles. Different match criteria were used and compared to determine the potential for Type I and Type II errors. It was determined that broader match criteria is more applicable to the forensic comparison of glass analysis because it can reduce the affect that micro-heterogeneity inherent in the glass fragments and a less than ideal sampling strategy can have on the interpretation of the results. Based on the test set reported here, a plus or minus four standard deviation (± 4s) match criterion yielded the lowest possibility of Type I and Type II errors. The developed LA-ICP-OES method has been shown to perform similarly to LA-ICP-MS in the discrimination among different sources of glass while offering the advantages of a lower cost of acquisition and operation of analytical instrumentation making ICP-OES a possible alternative elemental analysis method for the forensic laboratory.     

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.     

Analysis of glass fragments by laser ablation-inductively coupled plasma-mass spectrometry and principal component analysis

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is used to differentiate glass samples with similar optical and physical properties based on trace elemental composition. Laser ablation increases the number of elements that can be used for differentiation by eliminating problems commonly associated with dissolution and contamination. In this study, standard residential window and tempered glass samples that could not be differentiated by refractive index or density were successfully differentiated by LA-ICP-MS. The primary analysis approach used is Principal Component Analysis (PCA) of the complete mass spectrum. PCA, a multivariate analysis technique, provides rapid analysis of samples without time-consuming pair-wise comparison of calibrated analyses or prior knowledge of the elements present in the samples. Probabilities for positive association of the individual samples are derived from PCA. Utilization of the Q-statistic with PCA allowed us to distinguish all samples within the set to a certainty greater than the 99% confidence interval.     

Firing distance estimation through the analysis of the gunshot residue deposit pattern around the bullet entrance hole by inductively coupled plasma-mass spectrometry: an experimental study

The use of inductively coupled plasma-mass spectrometry (ICP-MS) in the study of gunshot residues (GSR) is relatively recent, and only a few studies have been published on the subject. In the present paper, this instrumental technique has been used to study the deposit pattern of the GSR around the bullet entrance hole, through the analysis of antimony (Sb), barium (Ba), and lead (Pb). The data obtained were used to establish a mathematical model for estimating the firing distance. Test shots using a 6.35-mm pistol were made against a target of cotton tissue, and the amounts of Sb, Ba, and Pb deposited in quadrangular pieces of the target, cut from 4 radial positions, were determined by ICP-MS. In these experimental conditions, it was possible to estimate the firing distance on the interval [20-80] cm. The best linear correlation between ln m and d, where m is the mass of Sb, Ba, or Pb in the samples, expressed in mug/g of target tissue, and d the firing distance, was obtained at radial distances between 3.5 cm and 4.5 cm from the entrance hole. The best regression curve which adjusted to the data was a linear multiple regression between the firing distance and the logarithm of the mass of each element: d = a + b(1)X(1) + b(2)X(2) + b(3)X(3), where X(1) = ln m (Sb), X(2) = ln m(Ba) and X(3) = ln m (Pb). The accuracy of firing distance estimation using only 1 or 2 elements was not significantly different from the one obtained with the 3 elements.     

Dilution in the United States and European Union (and beyond) Part II: testing for blurring

Legal context. Dilution by blurring has often been accused ofbeing a vague concept which is difficult to understand and whichhas no sensible limits. Mindful of the need for certainty inthis area, the US Senate and House of Representatives have passedthe Trademark Dilution Revision Act 2006. This Bill (which isdiscussed more generally in Part I) includes a definition ofblurring and a six-point test for blurring. Meanwhile, the EuropeanUnion has been steadily building up jurisprudence in this area. Key points. This part of the article focuses on dilution byblurring, considering how blurring is defined, how it is testedfor and whether US and EU blurring protection is in compliancewith the jurisdictions’ international obligations in thisarea (discussed in Part I). In particular, it considers thenew definition of, and test for, blurring under the US TrademarkDilution Revision Act 2006, and compares the position underthat Bill to the situation in the EU. Practical significance. Assuming that it enters into law, theRevision Act 2006 has serious implications for the proprietorsof famous marks doing business in the US. This article willinform the owners of such marks what protection they will benefitfrom and how this will differ from the protection they willget in the EU.     

微波消解ICP-MS法检测生物检材中汞元素

目的 建立生物检材中汞的电感耦合等离子体质谱分析方法.方法 采用微波消解法处理样品,以铟(115In)作内标,用电感耦合等离子体质谱仪对血液、尿液和头发中的汞含量进行分析.选择金与汞形成金汞齐,对金消除汞记忆效应的能力进行考察.结果 方法检出限为0.01μg/L,准确度为97.0%～107.1%.检测中添加金质量浓度在...     

Elemental analysis of bone: proton-induced X-ray emission testing in forensic cases

Proton-induced X-ray emission (PIXE) is a spectroscopic technique that provides the researcher with the elemental composition of a given target material. In this paper, we illustrate the utility of PIXE analysis in two forensic contexts: (1) case of cremation in which the nature of the remains is questioned and (2) cases of death by gunshot wound. In the first case, elemental analysis by PIXE reveals that the purported cremated remains are not bone. The last two cases show that radiopaque metallic residue embedded in bone is composed of lead from a projectile.     

Worldwide policy trends in agricultural extension: Part II

This second of a two-part article on global policy trends in agricultural extension deals with complexity. Policy differs enormously from country to country. The author believes that, rather than producing confusion and frustration in the field, the great variety of methodologies, institutional frameworks, and program priorities provides a rich field of ideas for study and practice. The major position in the article is that extension must be dealt with as part of a total agricultural-development process rather than an isolated subsystem for transferring technology to farmers.     

生物样品中的金属毒物电感耦合等离子发射光谱检验

目的建立有毒金属元素在肝、脾和肾脏组织中的快速检测方法。方法通过模拟样品,采用微波消解炉对样品进行预处理,用电感耦合等离子发射光谱仪同时对多种可疑有毒金属元素进行检测。结果在中毒剂量,对肝脏和肾脏组织中的可疑毒金属元素,可以采用电感耦合等离子发射光谱仪进行检测。     

Validity testing of commercial urine cocaine metabolite assays: II. Sensitivity, specificity, accuracy, and confirmation by gas chromatography/mass spectrometry

A comprehensive validity assessment study was performed on eight commercial urine assays for detection of cocaine use. Sensitivity, specificity, and accuracy of each assay were evaluated by analyzing, in random order and under blind conditions, specimens spiked with known drug concentrations and clinical specimens obtained from human subjects after intravenous cocaine use. Commercial assay results were compared with gas chromatography/mass spectrometry (GC/MS) assay of the same specimens for benzoylecgonine. All of the assays examined were determined to have utility in screening for cocaine use, with the exception of the KDI Quik Test, which was not a reliable test for detection of cocaine use. Major differences in sensitivity, specificity, and confirmation rate by GC/MS were noted among the assays, differences which should be taken into consideration when implementing a urine screening test for cocaine use or interpreting test results involving use of these assays.     

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.     

Measurement of airborne gunshot particles in a ballistics laboratory by sector field inductively coupled plasma mass spectrometry

The present study aimed determines lead (Pb), antimony (Sb) and barium (Ba) as the major elements present in GSR in the environmental air of the Ballistics Laboratory of the S?o Paulo Criminalistics Institute (I.C.-S.P.), S?o Paulo, SP, Brazil. Micro environmental monitors (mini samplers) were located at selected places. The PM(2.5) fraction of this airborne was collected in, previously weighted filters, and analyzed by sector field inductively coupled plasma mass spectrometer (SF-HR-ICP-MS). The higher values of the airborne lead, antimony and barium, were found at the firing range (lead (Pb): 58.9 μg/m(3); barium (Ba): 6.9 μg/m(3); antimony (Sb): 7.3 μg/m(3)). The mean value of the airborne in this room during 6 monitored days was Pb: 23.1 μg/m(3); Ba: 2.2 μg/m(3); Sb: 1.5 μg/m(3). In the water tank room, the air did not show levels above the limits of concern. In general the airborne lead changed from day to day, but the barium and antimony remained constant. Despite of that, the obtained values suggest that the workers may be exposed to airborne lead concentration that can result in an unhealthy environment and could increase the risk of chronic intoxication.