A concept study on identification and attribution profiling of chemical threat agents using liquid chromatography-mass spectrometry applied to Amanita toxins in food

Accidental or deliberate poisoning of food is of great national and international concern. Detecting and identifying potentially toxic agents in food is challenging due to their large chemical diversity and the complexity range of food matrices. A methodology is presented whereby toxic agents are identified and further characterized using a two-step approach. First, generic screening is performed by LC/MS/MS to detect toxins based on a list of selected potential chemical threat agents (CTAs). After identifying the CTAs, a second LC/MS analysis is performed applying accurate mass determination and the generation of an attribution profile. To demonstrate the potential of the methodology, toxins from the mushrooms Amanita phalloides and Amanita virosa were analyzed. These mushrooms are known to produce cyclic peptide toxins, which can be grouped into amatoxins, phallotoxins and virotoxins, where α-amanitin and β-amanitin are regarded as the most potent. To represent a typical complex food sample, mushroom stews containing either A. phalloides or A. virosa were prepared. By combining the screening method with accurate mass analysis, the attribution profile for the identified toxins and related components in each stew was established and used to identify the mushroom species in question. In addition, the analytical data was consistent with the fact that the A. virosa specimens used in this study were of European origin. This adds an important piece of information that enables geographic attribution and strengthens the attribution profile.     

Comparative Analysis of the Chemical Profiles of 3,4-Methylenedioxymethamphetamine Based on Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry (GC × GC-TOFMS)*

Abstract: The chemical profiling of illicit drugs is an important analytical tool to support the work of investigating and law enforcement authorities. In our work, comprehensive two‐dimensional gas chromatography–time‐of‐flight mass spectrometry (GC × GC‐TOFMS) combined with nontargeted, pixel‐based data analysis was adapted for the chemical profiling of 3,4‐methylenedioxymethamphetamine (MDMA). The validity and benefit of this approach was evaluated by analyzing a well‐investigated set of MDMA samples. Samples were prepared according to a harmonized extraction protocol to ensure the comparability of the chemical signatures. The nontargeted approach comprises preprocessing followed by analysis of variances as a fast filter algorithm for selection of a variable subset followed by partial least squares discriminant analysis for reduction to promising marker compounds for discrimination of the samples according to their chemical profile. Forty‐seven potential marker compounds were determined, covering most of the target impurities known from the harmonized one‐dimensional profiling as well as other compounds not previously elucidated.     

Detection of hemorrhage source: The diagnostic value of post-mortem CT-angiography

The aim of this study was to compare the diagnostic value of post-mortem computed tomography angiography (PMCTA) to conventional, ante-mortem computed tomography (CT)-scan, CT-angiography (CTA) and digital subtraction angiography (DSA) in the detection and localization of the source of bleeding in cases of acute hemorrhage with fatal outcomes. The medical records and imaging scans of nine individuals who underwent a conventional, ante-mortem CT-scan, CTA or DSA and later died in the hospital as a result of an acute hemorrhage were reviewed. Post-mortem computed tomography angiography, using multi-phase post-mortem CTA, as well as medico-legal autopsies were performed. Localization accuracy of the bleeding was assessed by comparing the diagnostic findings of the different techniques. The results revealed that data from ante-mortem and post-mortem radiological examinations were similar, though the PMCTA showed a higher sensitivity for detecting the hemorrhage source than did ante-mortem radiological investigations. By comparing the results of PMCTA and conventional autopsy, much higher sensitivity was noted in PMCTA in identifying the source of the bleeding. In fact, the vessels involved were identified in eight out of nine cases using PMCTA and only in three cases through conventional autopsy. Our study showed that PMCTA, similar to clinical radiological investigations, is able to precisely identify lesions of arterial and/or venous vessels and thus determine the source of bleeding in cases of acute hemorrhages with fatal outcomes.     

On non-invasive 2D and 3D Chromatic White Light image sensors for age determination of latent fingerprints

The feasibility of 2D-intensity and 3D-topography images from a non-invasive Chromatic White Light (CWL) sensor for the age determination of latent fingerprints is investigated. The proposed method might provide the means to solve the so far unresolved issue of determining a fingerprints age in forensics. Conducting numerous experiments for an indoor crime scene using selected surfaces, different influences on the aging of fingerprints are investigated and the resulting aging variability is determined in terms of inter-person, intra-person, inter-finger and intra-finger variation. Main influence factors are shown to be the sweat composition, temperature, humidity, wind, UV-radiation, surface type, contamination of the finger with water-containing substances, resolution and measured area size, whereas contact time, contact pressure and smearing of the print seem to be of minor importance. Such influences lead to a certain experimental variability in inter-person and intra-person variation, which is higher than the inter-finger and intra-finger variation. Comparing the aging behavior of 17 different features using 1490 time series with a total of 41,520 fingerprint images, the great potential of the CWL technique in combination with the binary pixel feature from prior work is shown. Performing three different experiments for the classification of fingerprints into the two time classes [0, 5h] and [5, 24h], a maximum classification performance of 79.29% (kappa=0.46) is achieved for a general case, which is further improved for special cases. The statistical significance of the two best-performing features (both binary pixel versions based on 2D-intensity images) is manually shown and a feature fusion is performed, highlighting the strong dependency of the features on each other. It is concluded that such method might be combined with additional capturing devices, such as microscopes or spectroscopes, to a very promising age estimation scheme.     

Raman spectroscopy and microspectrophotometry of reactive dyes on cotton fibres: Analysis and detection limits

A collaborative study on Raman spectroscopy and microspectrophotometry (MSP) was carried out by members of the ENFSI (European Network of Forensic Science Institutes) European Fibres Group (EFG) on different dyed cotton fabrics. The detection limits of the two methods were tested on two cotton sets with a dye concentration ranging from 0.5 to 0.005% (w/w). This survey shows that it is possible to detect the presence of dye in fibres with concentrations below that detectable by the traditional methods of light microscopy and microspectrophotometry (MSP). The MSP detection limit for the dyes used in this study was found to be a concentration of 0.5% (w/w). At this concentration, the fibres appear colourless with light microscopy. Raman spectroscopy clearly shows a higher potential to detect concentrations of dyes as low as 0.05% for the yellow dye RY145 and 0.005% for the blue dye RB221. This detection limit was found to depend both on the chemical composition of the dye itself and on the analytical conditions, particularly the laser wavelength. Furthermore, analysis of binary mixtures of dyes showed that while the minor dye was detected at 1.5% (w/w) (30% of the total dye concentration) using microspectrophotometry, it was detected at a level as low as 0.05% (w/w) (10% of the total dye concentration) using Raman spectroscopy. This work also highlights the importance of a flexible Raman instrument equipped with several lasers at different wavelengths for the analysis of dyed fibres. The operator and the set up of the analytical conditions are also of prime importance in order to obtain high quality spectra. Changing the laser wavelength is important to detect different dyes in a mixture.     

Genetic and chemical components analysis of Papaver setigerum naturalized in Korea

Of the 110 species of genus Papaver, only Papaver somniferum and P. setigerum are controlled poppies in Korea. All poppy samples share similar morphology therefore it is important to check if they contain controlled substances such as morphine and codeine for forensic purpose. Since the alkaloid content of Papaver plants varies according to their growing stage, chemical components analysis alone is not enough to identify exact species. In 2010, hundreds of poppy plants suspected to be P. somniferum were found in Jeju Island, South Korea. They had a slightly different but overall similar appearance to P. somniferum. Using GC-MS analysis, codeine, rhoeadine, papaverine, protopine, noscapine, setigeridine and trace amounts of morphine were detected in these samples. Although their chemical components were different from what has been described in literatures for P. setigerum, they could be assumed to be P. setigerum based on their morphological features and GC-MS results. Also, chromosome numbers using their seeds showed 2n=44 and the numbers were in accordance with those of P. setigerum. Nucleotide substitution or insertion/deletion of ITS (internal transcribed spacer), 18S rRNA (ribosomal RNA), rbcL (large subunit of ribulose 1,5-bisphosphate carboxylase), trnL-trnF IGS (intergenic spacer), trnL intron and psbA-trnH were assessed as universal genetic markers for P. setigerum. Also, genetic analysis using six target genes involved in the biosynthesis of benzylisoquinoline alkaloids, including TYDC (tyrosine/dopa decarboxylase), SAT (salutaridinol-7-O-acetyltransferase), BBE (berberine bridge enzyme), COR (codeinone reductase), CYP80B1 ((S)-N-methylcoclaurine 3'-hydroxylase) and NCS (norcoclaurine synthase) were tested as Papaver-specific genetic markers by the existence of their PCR products. From the results, the sequences of the 6 universal genetic markers and 6 Papaver-specific genetic markers for P. setigerum were identified and then Genbank accession numbers of them were registered in NCBI. Also, the trnL intron and psbA-trnH nucleic acid sequences of the 7 Papaver species were identified and registered.     

和谐地税惠民生——陕西省地方税务局发挥职能作用，助推经济社会发展纪实

2011年,陕西省地方税务局在省委、省政府的正确领导下,在省人大、省政协的监督支持下,坚持以科学发展观为统领,以服务科学发展、促进社会和谐为己任,深入践行科学发展观,不断强化“聚财为国、执法为民”的责任意识,深化税收改革,优化纳税服务,外树形象,内强素质,凝心聚力,锐意创新,使税收职能作用得到充分发挥,地税税收收入实现较大持续快速增长,为陕西经济社会建设、民生改善提供了有力的财力保障。     

The changes of fourier transform infrared spectrum in rat brain

Estimation of the time since death (postmortem interval [PMI]) is one of the most difficult problems in forensic investigations, and many methods currently are utilized to estimate the PMI. The goal of this study was to investigate the changes of attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectra of rat brain from postmortem time 0-144 h. The intensity ratios of major absorbance bands were examined (I(1066)/I(1392), I(1168)/I(1392), I(1234)/I(1454), I(1301)/I(1392), I(1647)/I(2956), I(2921)/I(2850), and I(1647)/I(1539)). The spectra of rat brain displayed prominent changes with increasing PMI. The band at 2871 and 1737 per cm became weak with the time increasing and even disappeared at postmortem 96 and 72 h, respectively. A close linear correlation was shown between the relative absorption intensity and the PMI, and the I(1234) /I(1454) offered a stronger correlation (r = 0.973). Our results indicate that ATR-FTIR spectroscopy may be a useful technique for estimating the PMI.     

The AFSP Standard - a lesson for law enforcement agencies

Compliance with the AFSP (Association of Forensic Science Providers) Standard [1] which concerns the formulation of an evaluative opinion requires consideration of the defence case. This can be problematic for forensic scientists working with or for law enforcement agencies. Among the aims of law enforcement agencies is to secure a conviction while in many jurisdictions the forensic scientist owes an overriding duty to the Court. This casework report demonstrates that early consideration of the defence case by a forensic scientist complying with the AFSP Standard may help rather than hinder the prosecution. The dichotomy as to a conflict of interest for the scientist between supporting the police/prosecutors and being scientifically objective is shown to be a false dichotomy. Compliance with the Standard ensures that science is a better servant of justice.     

Determination of the sequence of intersecting lines from laser toner and seal ink by Fourier transform infrared microspectroscopy and scanning electron microscope / energy dispersive X-ray mapping

The aim of this study was to verify that the combination of Fourier transform infrared microspectroscopy and scanning electron microscope / energy dispersive X-ray mapping could be applied to line intersection problems. The spectral data of red seal ink, laser toner and their intersections, such as peak location and peak intensity, were described. Relative peak height ratios of different chemical components in intersecting lines were used to distinguish the sequences. Energy dispersive X-ray mapping characteristics of intersecting areas were also detailed. The results show that both the laser toner and the seal ink appear on the surface of intersections, regardless of the sequence. The distribution of the two inks on the surface is influenced not only by the sequence of heterogeneous lines but also by diffusion. Fourier transform infrared microspectroscopy and scanning electron microscope/energy dispersive X-ray mapping are able to explore the chemical components and the corresponding elemental distribution in the intersections. The combination of these two techniques has provided a reliable method for sequencing intersecting lines of red seal ink and laser toner, and more importantly, this method may be a basis for sequencing superimposed lines from other writing instruments.