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...     

Identification of gunshot residues in fabric targets using sector field inductively coupled plasma mass spectrometry technique and ternary graphs

During criminal investigations involving firearms, the detection of gunshot residues (GSRs) is one of the most important evidences. In the present study, a new method to identify trace evidences of GSRs, deposited around the bullet entrance hole, in different types of fabrics used as targets, is described. The experiments were carried out using a 0.38-inch caliber revolver, and 9-mm and 0.40-inch caliber pistols. Testimonies of 2.25 cm(2) of the fabrics were cut around the bullet entrance and digested with 10% nitric acid. Antimony, barium, and lead were analyzed in the remaining solution using a sector field inductively coupled plasma mass spectrometer. The concentrations of the elements were detected at levels up to few microgram per square centimeter. The use of ternary graphics allowed us to identify specific patterns of distribution for blank samples and the clear distinction between the revolver and pistols used.     

Characterization of Undigested Particulate Material Following Microwave Digestion of Recycled Document Papers

Abstract:  Recycled document paper was microwave digested in a solution of HNO₃ and H₂O₂ prior to analysis by inductively coupled plasma mass spectrometry (ICP-MS) to determine the trace elemental concentrations within the paper. Undigested particulate material was observed and subsequently characterized as a mixture of kaolin (clay) and TiO₂ by Fourier transform infrared spectroscopy and X-ray diffraction spectroscopy. The effect of the particulate material on the elemental concentrations was then investigated. Paper samples were completely digested in hydrofluoric acid (HF) and element concentrations determined in the HF and HNO₃/H₂O digests were statistically compared using Student's t -test (95% confidence limit). Statistical differences in element concentrations between the two digests were observed for only four elements and there was no evidence of element adsorption by the particulate material. Hence, the HNO₃/H₂O₂ digestion proved sufficient to digest paper for ICP-MS analysis, eliminating the need to use the hazardous and corrosive HF matrix.     

Determination of Trace Elemental Concentrations in Document Papers for Forensic Comparison Using Inductively Coupled Plasma–Mass Spectrometry

Abstract:  With improvements in manufacturing procedures, comparing physical characteristics of paper samples may not offer sufficient discrimination among different vendors. In this work, the potential to differentiate paper samples based on trace element concentrations was investigated. Paper samples from two different vendors were microwave-digested and trace element concentrations (Mg, Al, Mn, Fe, Sr, Y, Ba, Ce, and Nd) were determined using inductively coupled plasma–mass spectrometry. Differences in concentration were assessed statistically using two-way ANOVA and Tukey's honestly significant differences test. Elemental concentrations were shown to be consistent across a single sheet as well as within a single ream of paper for each vendor. Reams from vendor A were differentiated based on Al and Ba concentration while reams from vendor B were differentiated based on Mg, Mn, and Sr concentrations. Paper was differentiated according to vendor based on significant differences in Ba, Sr, Ce, and Nd concentrations.     

Detection of Gunshot Residue in Blowfly Larvae and Decomposing Porcine Tissue Using Inductively Coupled Plasma Mass Spectrometry (ICP‐MS)*

Abstract: Blowfly larvae and porcine tissue contaminated with gunshot residue (GSR) were collected during summer and winter months, over a 37‐day and a 60‐day sampling period, respectively. Wound samples were microwave‐digested and analyzed by inductively coupled plasma mass spectrometry (ICP‐MS) for the detection of antimony, barium, and lead. During summer, the 37‐day sampling period encompassed all stages of decomposition, except skeletonization. The three elements were detected in larvae only on days 3 and 4 after death but were detected at significant levels in tissue samples throughout the entire sampling period. In winter, no significant decomposition was observed throughout the 60‐day sampling. Although temperatures were too low for blowfly activity, the three elements were detected in the tissue samples at relatively constant, significant levels. Hence, GSR determination in tissue was more dependent on decomposition stage rather than time since death.     

Visualization of gunshot residue patterns on dark clothing

ABSTRACT: Determination of the muzzle‐to‐target distance is often a critical factor in criminal and civil investigations involving firearms. However, seeing and recording gunshot residue patterns can be difficult if the victim's clothing is dark and/or bloodstained. Trostle reported the use of infrared film for the detection of burn patterns. However, only after the film is developed are the results visible and multiple exposures at different settings may be needed. The Video Spectral Comparator^? 2000 (Foster & Freeman Ltd., Evesham, Worcestershire, U.K.) is an imaging instrument routinely used by forensic document examiners. Without use of specialized film could the VSC 2000 (at appropriate instrument settings) quickly, easily, and reliably provide instantaneous viewing, saving, and printing of gunshot residue patterns on dark and/or blood soaked clothing? At muzzle‐to‐target distances of 6, 12, and 18 in., test fires were made into five different types of dark clothing using eight different handguns of different calibers. Gunshot residues were detected for all eight calibers, and powder burn patterns were seen on dark clothing for all three target distances and calibers except 0.22 long rifle and 0.25 ACP. Bloodstains did not preclude the viewing of these patterns.     

Detection of Pb,Ba, and Sb in Cadaveric Maggots and Pupae by ICP-MS*

The concentrations of lead (Pb), barium (Ba), and antimony (Sb), characteristic of GSR, were determined in soil sediments and immature (larvae) of cadaveric flies of the family Calliphoridae, by inductively coupled plasma mass spectrometry (ICP-MS). This research refers to a case study from two real crime scenes in which the corpses were in an advanced state of decomposition. In case 1, the victim had holes similar to gunshot wounds, and in case 2, there was no evidence of perforations in the corpse. Soil sediment collection was performed at three different points of the terrain, at a minimum distance of 10 m from the corpse, for cases 1 and 2. In relation to the collection of immatures, larvae were collected in regions of the mouth, nose, and orifices similar to the entry of firearms projectile into the body, for case 1, and collection of larvae and pupae, located on the body and underneath it, for case 2. It was possible to detect and quantify the three elements of interest (Pb, Ba, and Sb) by ICP-MS in both sediment and cadaveric larvae. Concentrations of 4.44, 8.74, and 0.08 μg/g were obtained for Pb, Ba, and Sb, respectively, in the soil for case 1. For the case 2, the concentrations in Pb, Ba, and Sb were from 16.34 to 26.02 μg/g; from 32.64 to 57.97 μg/g and from 0.042 to 0.30 μg/g, respectively. In the larvae, Pb, Ba, and Sb were quantified in cases 1 and 2 with a concentration of 6.28 and 1.78 μg/g for Pb, 1.49 and 2.94 μg/g for Ba, 0.50 μg/g and <LD for Sb, respectively. These new results present the detection of characteristic elements of GSR in cadaveric larvae in humans in a real crime scene, besides highlighting the importance of the study of immature flies, using the ICP-MS technique in forensic analysis.     

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。     

微波消解ICP-MS法测定人头发中24种元素的含量

目的建立人头发中24种无机元素的电感耦合等离子体质谱（inductively coupled plasma-mass spec-trometry,ICP-MS）分析方法。方法采用微波消解法处理样品,以铟（115In）作内标,用ICP-MS分析人头发中的24种元素含量。同时检测56例健康志愿者和10例海洛因滥用者头发中24种元素含量。结果 24种元素的方法检出限范围为0.0003~10.14μg/g,标准物质的测得值与标准值基本相符。海洛因滥用者经戒毒治疗后头发中镁、镓、钡含量下降。结论该方法灵敏度、准确度高,适用于头发中24种元素的测定。     

Trace element fingerprinting of Australian ocher using laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS) for the provenance establishment and authentication of indigenous art

The expansion of indigenous art and the interest it has generated both at a domestic and international level means large monetary transactions are taking place between art galleries or centers and purchasers. As such, an accurate and conclusive method for provenance determination of traditional indigenous artistic materials must be established that can, if necessary, be used to assist in authentication of artworks. Laser ablation inductively coupled plasma mass spectrometry was utilized for elemental differentiation and provenance establishment of ocher samples. This research was used to develop a robust scientific protocol which facilitates definitive and accurate determination of provenance of Australian ochers and the artworks created using them. Analysis of the results obtained through this study show that the trace metal distribution patterns alone appear to be sufficient evidence to establish provenance of specific ochers, although additional differentiation between ocher samples, using major element distribution patterns, was achieved through the utilization of X-ray analytical techniques.     

A method for enhancing gunshot residue patterns on dark and multicolored fabrics compared with the modified Griess test

In using infrared or infrared-enhanced photography to examine gunshot residue (GSR) on dark-colored clothing, the GSR particles are microscopically examined directly on the fabric followed by the modified Griess test (MGT) for nitrites. In conducting the MGT, the GSR is transferred to treated photographic paper for visualization. A positive reaction yields an orange color on specially treated photographic paper. The examiner also evaluates the size of the powder pattern based on the distribution of nitrite reaction sites or density. A false-positive reaction can occur using the MGT due to contaminants or dyes that produce an orange cloud reaction as well. A method for enhancing visualization of the pattern produced by burned and partially unburned powder is by treatment of the fabric with a solution of sodium hypochlorite. In order to evaluate the results of sodium hypochlorite treatment for GSR visualization, the MGT was used as a reference pattern. Enhancing GSR patterns on dark or multicolored clothing was performed by treating the fabric with an application of 5.25% solution of sodium hypochlorite. Bleaching the dyes in the fabric enhances visualization of the GSR pattern by eliminating the background color. Some dyes are not affected by sodium hypochlorite; therefore, bleaching may not enhance the GSR patterns in some fabrics. Sodium hypochlorite provides the investigator with a method for enhancing GSR patterns directly on the fabric. However, this study is not intended to act as a substitute for the MGT or Sodium Rhodizonate test.     

Provenance determination of oriental porcelain using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS)

The sale of fraudulent oriental ceramics constitutes a large proportion of the illegal artifact and antique trade and threatens to undermine the legitimate international market. The sophistication and skill of forgers has reached a level where, using traditional appraisal by eye and hand, even the most experienced specialist is often unable to distinguish between a genuine and fraudulent piece. In addition, current provenancing techniques such as energy-dispersive X-ray fluorescence (EDXRF) spectrometry and thermoluminescence (TL) dating can result in significant damage to the artifact itself. Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), a relatively nondestructive analytical technique, has been used for the provenance determination of materials based on geographical origin. The technique requires the production of a laser crater, c. 100 microm in diameter, which is essentially invisible to the naked eye. Debris from this crater is analyzed using ICP-MS, with the results forming the basis of the provenance establishment protocol. Chinese, Japanese, and English porcelain shards have been analyzed using this protocol and generic isotopic distribution patterns have been produced that enable the provenance establishment of porcelain artifacts to their country of production. Minor variations between elemental fingerprints of artifacts produced in the same country also indicate that it may be possible to further provenance oriental ceramics to a specific production region or kiln site.     

The Survival of Gunshot Residues in Cremated Bone: An Inductively Coupled Plasma Optical Emission Spectrometry Study

Gunshot residue (GSR) has been sought and demonstrated on many types of material and with many techniques. Inductively coupled plasma optical emission spectrometry (ICP‐OES) could be a useful method on difficult substrates, but a systematic study on burnt material has never been performed. Hence, this study aims at evaluating the usefulness and reliability of this method on burnt samples. Sixteen adult bovine ribs (eight with soft tissues, eight totally skeletonized) were shot using two kinds of projectile (both 9 mm full metal‐jacketed or unjacketed). Then, every sample was led to complete calcination in an electric oven. The area of the gunshot entrance wound was swabbed and analyzed by ICP‐OES; the results were also correlated with a previously published parallel study by scanning electron microscopy (SEM) equipped with an SEM–energy dispersive X‐ray analyzer. ICP‐OES proved to be very sensitive and reliable even on degraded material and can be an appropriate nondestructive method for detecting residues on difficult and delicate substrates such as burnt bone.     

The Analysis of Gun‐Cleaning Oil as Long‐Distance Gunshot Residue and Its Implications for Chemical Tags on Bullets

Using a BB gun, it was shown that a gun‐cleaning oil (GCO) can be wiped from the barrel by a projectile and carried much longer distances than those usually associated with solid gunshot residue (GSR). Analysis of GCO subsequently deposited on a target was performed using pentane extraction and gas chromatography. (Hoppe's GCO was used here as a model.) When a 0.45 caliber handgun was used, analysis reveals that most of the GCO wiped from the barrel does not survive, owing to the elevated temperatures encountered. However, two components of the GCO, a long‐chain fatty acid and its ethyl ester, do survive and can be detected in the bullet wipe. This suggests that GCO may be considered as GSR, uniquely detectable at long distances, and that other chemical compounds could either be added to a GCO or directly to bullets, to serve as identifying chemical tags.     

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.     

微波消解ICP-MS法测定人发中的汞

目的建立人发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分析人发中的汞含量。结果方法检出限为0.0032μg/g,准确度通过测定人发标准物质GBW07601、GBW09101b进行验证,检测结果与标准参考值相符。结论该方法快捷、高效,灵敏度、准确度高,适用于人发中汞含量的检测。     

Differentiating writing inks using direct analysis in real time mass spectrometry

Writing ink analysis is used in establishing document authenticity and the sources and relative ages of written entries. Most analytical methods require removing samples or visibly altering the document. Nondestructive, in situ analysis of writing inks on paper without visible alteration is possible using mass spectrometry with a new ion source called Direct Analysis in Real Time. Forty-three different black and blue ballpoint, black fluid, and black gel inks were examined. Both dyes and persistent but thermally labile components of the inks contribute to the mass spectra, principally as protonated molecules [M+H](+). Numerous ink components were identified from the spectra. The spectra were placed in a searchable library, which was then challenged with two spectra from each of the 43 inks. The best match for each of the challenge spectra was correct for all but one ink, which matched with a very similar ink by the same manufacturer.     

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.     

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。     

激光剥蚀电感耦合等离子体质谱技术检测车辆油漆金属元素

目的建立车辆油漆的激光剥蚀电感耦合等离子体质谱（laser ablation inductively coupled plasma mass spectrometry,LA—ICP—MS）分析方法。方法对38种车辆油漆样品采用激光剥蚀,电感耦合等离子体质谱进行测定,通过各油漆样品本含有金属元素种类和金属元素响应相对比值的差异对油漆样品进行区分。结果38种样品中有30种可直接依据所含金属元素种类的差异进行对其进行区分,其余8种依据元素间响应值比值的差异进行区分,方法重现性良好,精密度（RSD）小于10％。结论所建立的LA—ICP—MS方法简便快速、精密度良好、对样品微损,适用于法庭科学对车辆油漆的检测。