Raman Spectroscopic Differences between Ephedrine and Pseudoephedrine

Ephedrine (EPH) and pseudoephedrine (PSE) were studied by micro‐Raman spectroscopy and UV resonance Raman spectroscopy excited at 785 and 360 nm, respectively. Raman bands at approximately 245 and 410 cm^?1 for ephedrine have apparent differences from the same bands at approximately 215, 265, 350, 450, and 555 cm^?1 for pseudoephedrine, and these differences can be applied to distinguish between EPH and PSE. Additionally, density functional theory was used for the Raman calculations to obtain results identical to the experimental spectra. This work is expected to expand the applications of Raman spectroscopy in forensic science.     

Powdered Activated Carbon: An Alternative Approach to Genomic DNA Purification

Forensic evidence samples are routinely found as stains on various substrates, which may contain substances known to inhibit polymerase chain reaction (PCR). The goal of this study was to evaluate post‐Chelex^®100 purification using powdered activated carbon (PAC). Mock crime scene DNA extracts were analyzed using quantitative PCR and short tandem repeat (STR) profiling to test the DNA recovery and inhibitor removal using PAC with those of the Amicon^®Ultra 100K. For extracted bloodstains on soil and wood substrates, PAC and Amicon^®Ultra 100K generated similar DNA yield and quality. Moreover, the two methods significantly decreased the concentration of humic substances and tannins compared to nonpurified extracts (p < 0.001). In instances where extracts contained indigo dye (bloodstains on denim), Amicon^®Ultra 100K performed better than PAC due to improved amplifiability. Efficient adsorption of humic substances and tannins, which are common inhibitors, indicates PAC's potential application in the purification of high‐template DNA extracts.     

Development of a Protein‐based Human Identification Capability from a Single Hair

Shed human hair (lacking root nuclear DNA) frequently contributes important information to forensic investigations involving human identification. Detection of genetic variation observed in amino acid sequences of hair proteins provides a new suite of identity markers that augment microscopic hair analysis and mitochondrial DNA sequencing. In this study, a new method that completely dissolves single hairs using a combination of heat, ultrasonication, and surfactants was developed. Dissolved proteins were digested and genetically variant peptide (GVP) profiles were obtained for single hairs (25 mm) via high‐resolution nanoflow liquid chromatography‐based mass spectrometry and a novel exome‐driven bioinformatic approach. Overall, 6519 unique peptides were identified and a total of 57 GVPs were confirmed. Random match probabilities ranged between 2.6 × 10^?2 and 6.0 × 10^?9. The new bioinformatic strategy and ability to analyze GVPs in forensically relevant samples sizes demonstrate applicability of this approach to distinguish individuals in forensic contexts.     

Estimating Time Since Death from Postmortem Human Gut Microbial Communities

Postmortem succession of human‐associated microbial communities (“human microbiome”) has been suggested as a possible method for estimating postmortem interval (PMI) for forensic analyses. Here we evaluate human gut bacterial populations to determine quantifiable, time‐dependent changes postmortem. Gut microflora were repeatedly sampled from the proximal large intestine of 12 deceased human individuals as they decayed under environmental conditions. Three intestinal bacterial genera were quantified by quantitative PCR (qPCR) using group‐specific primers targeting 16S rRNA genes. Bacteroides and Lactobacillus relative abundances declined exponentially with increasing PMI at rates of N_t = 0.977e^?0.0144t (r² = 0.537, p < 0.001) and N_t = 0.019e^?0.0087t (r² = 0.396, p < 0.001), respectively, where N_t is relative abundance at time (t) in cumulative degree hours. Bifidobacterium relative abundances did not change significantly: N_t = 0.003e^?0.002t (r² = 0.033, p = 0.284). Therefore, Bacteroides and Lactobacillus abundances could be used as quantitative indicators of PMI.     

Sickle Cell Trait as a Contributory Cause of Death in Natural Disease

Sickle cell trait (SCT) affects 300 million people globally, and awareness is growing that SCT is not an entirely benign condition; however, most reported cases have been non‐natural deaths. Autopsy records from the Baylor University Medical Center (BUMC) in Dallas, Texas, contained seven natural deaths from January 2007 to October 2013 in which micro‐occlusive sickling was identified at autopsy and SCT confirmed by postmortem hemoglobin fractionation. Sickle crisis was never diagnosed clinically. These cases illustrate the importance of red cell morphology in autopsy material. When sickling is suspected, hemoglobin fractionation should be performed. If confirmed, SCT should be listed as an autopsy finding and the severity and distribution of sickling documented. Extensive micro‐occlusive sickling should be considered contributory to death; however, its relative importance depends on all facts of the case. Accurate reporting should facilitate further research and the development of evidence‐based preventative and supportive strategies for these patients.     

Potential for the Remediation of Methamphetamine Contamination Using Ozone,

The deposition of methamphetamine within indoor environments due to illegal activities can pose a health risk for occupants. Current cleaning techniques are costly and inefficient, calling for the development of alternative remediation methods. In addition, the fate of methamphetamine in indoor environments is largely unknown, negatively impacting our knowledge on the health risks associated with contaminated dwellings. Under the conditions of this study, 97% of surface deposited methamphetamine on a paper substrate was consumed after 12 min of exposure to ozone, thus demonstrating potential for its use as a remediation agent. The reaction had an effective second‐order rate constant with an upper limit of 2.15 ± 1 × 10^?18 cm³/molecule/s, and the main product observed was phenyl‐2‐propanone (P2P) at 8.3% yield, as determined using GC/MS. Several products observed in this study have also been reported as by‐products of methamphetamine synthesis, including P2P—a known methamphetamine precursor, which indicates that their detection at a potential clandestine site is not necessarily evidence of manufacture.     

A Comparison of DNA Extraction Using AutoMate Express™ and EZ1 Advanced XL from Liquid Blood,Bloodstains, and Semen Stains

In this study, DNA was extracted using an AutoMate Express? and an EZ1 Advanced XL from liquid blood, fresh and aged bloodstains, and fresh and aged semen stains. Extracted DNA was quantified by real‐time PCR using the D17Z1 locus. Short tandem repeat typing was performed using an AmpF?STR^® Identifiler kit. The yields of DNA obtained by the AutoMate Express? were higher from fresh bloodstains and fresh semen stains, almost the same from aged bloodstains and aged semen stains, but slightly lower from liquid blood compared with those obtained by the EZ1 Advanced XL. The addition of dithiothreitol or the use of PrepFiler? lysis buffer improved the EZ1 Advanced XL results from fresh bloodstains, but not for liquid blood and aged bloodstains. Our results demonstrated that the PrepFiler? lysis buffer is the main contributor to the higher DNA yields of the AutoM ate Express? for fresh bloodstains.     

A City‐wide Investigation of the Isotopic Distribution and Source of Tap Waters for Forensic Human Geolocation Ground‐truthing

Human geolocation is prefaced on the accuracy of the geographic precision of mapped isotopic values for drinking water. As most people live in cities, it becomes important to understand city water supplies and how the isotopic values uniquely reflect that city. This study investigated the isotopic distribution of δ²H and δ¹⁸O from sourced tap waters that were collected from across the Metro Vancouver (MV) area (n = 135). The results revealed that the isotopic values reflect their water sources with a range of 5.3‰ for δ¹⁸O_tap and 29.3‰ for δ²H_tap for MV. The results indicate that individual cities need higher resolution studies to determine their tap water isotopic ranges, and a good understanding of the water supply network itself for human geolocation work. With an extended high‐resolution understanding of each city, human tissue may be compared with more certainty for geolocation.     

Estimating postmortem interval for human cadavers in a sub‐tropical climate using UV‐Vis‐near‐infrared Spectroscopy

Estimating postmortem interval (PMI) of surface found skeletal remains is challenging. This novel study used UV‐Vis‐NIR spectroscopy to scan soil collected from cadaver decomposition islands (CDIs) ranging from 15‐ to 963‐d postmortem and control soils. A decomposition product spectra model (DPS model) was constructed by deducting the control soil spectra from the CDI soil spectra for the estimation of postmortem indices: PMI (d), ADD₄, ADD₁₀, and ADD₂₀. The DPS model (n = 55) was calibrated and subjected to a full cross‐validation. Calibration R² and RPD for the DPS model ranged from 0.97 to 0.99 and from 6.1 to 9.9, respectively, for the four postmortem interval indices. Validation R² and RPD for the DPS model ranged from 0.73 to 0.80 and from 1.9 to 2.2, respectively. The DPS model estimated postmortem intervals for three test CDIs in a clay soil under perennial grassland (test set 1; n = 3) and six CDIs in a sandy soil under a loblolly pine forest (test set 2; n = 6). Test set 1 had PMI prediction ranges from ?69 to ?117 days, ?796 to +832 ADD₄, +552 to +2672 ADD₁₀, and ?478 to ?20 ADD₂₀ of observed PMI. Test set 2 PMI prediction ranged from ?198 to ?65 days, ?9923 to +2629 ADD₄, ?6724 to +1321 ADD₁₀, and ?2850 to +540 ADD₂₀ of observed PMI. Test set 2 had poor predictions for two CDIs, for all measures of postmortem indices resulting in discussion of sampling depth, effect of body mass index (BMI), and scavenging.     

In situ Study on the Diffusion Kinetics of Seal Ink by Microinfrared Spectroscopy

In document examination, it is of great importance to determine the composition of seal ink with different imprint times, and spectroscopic methods are widely used today. In this research, the diffusion of seal inks from three different brands on the same type of paper is monitored in situ by microinfrared spectroscopy and microinfrared imaging technology. The area of the absorption peak at 1743 cm^?1 gradually decreases with increasing diffusion time. The diffusion kinetics of seal ink on paper are also studied by analyzing the infrared spectra of seal inks at the same measuring point with different diffusion times. The research provides a basic study in understanding the diffusion behavior of seal ink on paper over short time spans.     

Infrared Spectra of U.S. Automobile Original Finishes (Post – 1989). VIII: In Situ Identification of Bismuth Vanadate Using Extended Range FT‐IR Spectroscopy,Raman Spectroscopy,and X‐Ray Fluorescence Spectrometry

Chrome Yellow (PbCrO₄·xPbSO₄) was a common pigment in U.S. automobile OEM finishes for more than three decades, but in the early 1990s its use was discontinued. One of its main replacements was Bismuth Vanadate (BiVO₄·nBi₂MoO₆, n = 0–2), which was commercially introduced in 1985, as this inorganic pigment also produces a very bright hue and has excellent outdoor durability. This paper describes the in situ identification of Bismuth Vanadate in automotive finishes using FT‐IR and dispersive Raman spectroscopy and XRF spectrometry. Some differentiation of commercial formulations of this pigment is possible based on far‐infrared absorptions, Raman data, and elemental analysis. The spectral differences arise from the presence or absence of molybdenum, the use of two crystal polymorphs of BiVO₄, and differences in pigment stabilizers. Bismuth Vanadate is usually not used alone, and it is typically found with Isoindoline Yellow, hydrous ferric oxide, rutile, Isoindolinone Yellow 3R, or various combinations of these.     

The Use of Forensic Tests to Distinguish Blowfly Artifacts from Human Blood,Semen, and Saliva

This study investigated whether routinely used forensic tests can distinguish 3‐day‐old or 2‐week‐old fly artifacts, produced after feeding on human blood, semen, or saliva, from the biological fluid. Hemastix^®, Hemident^?, and Hemascein^? were unable to distinguish blood from artifacts. Hemastix^® returned false positives from negative controls. ABAcard^® Hematrace^® and Hexagon OBTI could distinguish blood from 3‐day‐old artifacts, but not 2‐week‐old artifacts. Phadebas^® and SALIgAE^® were unable to distinguish saliva from artifacts. RSID^?‐Saliva was able to distinguish saliva from 3‐day‐old artifacts, but not 2‐week‐old artifacts. Semen tests Seminal Acid Phosphatase, RSID^?‐Semen, and ABAcard^® p30 were all able to distinguish semen from 3‐day‐old artifacts, but not 2‐week‐old artifacts. The tests investigated cannot be relied upon to distinguish artifacts from biological fluids. However, if an artifact is identified by its morphology, a positive result may indicate which biological fluid the fly consumed, and this knowledge may prove useful for investigators searching for DNA.     

Field Study on the Attraction and Development of Insects on Human Meconium and Breast‐fed‐Infant Feces

Urogenital myiasis of newborn infants, although rare, is usually considered to indicate neglect due to attraction of flies to feces; however, infant feces have not been determined to attract insects. Human meconium and breast‐fed‐infant feces were used to determine attractiveness to insects and to examine subsequent colonization and growth patterns of insect larvae. Despite small amounts of fecal material present, adults of Lucilia sericata arrived at breast‐fed‐infant feces within five minutes; insects were rarely observed on meconium. Oviposition and growth of L. sericata larvae occurred only on breast‐fed‐infant feces; however, the larvae did not progress beyond the second instar. These data suggest that urogenital myiasis by L. sericata in newborn human infants within the first few days postpartum would not be expected, but desiccation and depletion of infested feces may provide a possible pathway for urogenital myiasis in older newborn infants.     

Refining Stable Oxygen and Hydrogen Isoscapes for the Identification of Human Remains in Mississippi,

Isoscape refinement is an essential component for accurately predicting region‐of‐origin in forensic investigations involving isotope analysis of unidentified human remains. Stable oxygen (δ¹⁸O) and hydrogen (δ²H) isotopes were measured from 57 tap water samples collected across Mississippi to model refined isoscapes for the state. A tap water conversion equation, δ¹⁸O_tw=1.64 δ¹⁸Op?31.35, was developed for the southeastern USA to test the prediction accuracy of the δ¹⁸O_tw isoscape using individuals with known residential histories. A local Mississippi resident (USAFA‐134) was assigned with 90% probability to the correct region‐of‐origin reported by the participant. Assignments for Georgia residents (USAFA‐118 and USAFA‐205) had variable results, predicting USAFA‐118 from Mississippi and USAFA‐205 as a nonlocal resident. Stable isotope values often overlap geographically and a multi‐isotope approach should be used when narrowing region(s)‐of‐origin(s). This study demonstrates the utility of refining isoscapes and the importance of tissue calibration in prediction assignments of human remains.     

The NucleoSpin DNA Clean-up XS kit for the concentration and purification of genomic DNA extracts: An alternative to microdialysis filtration

Traditionally, DNA extracts from biological evidence items have been concentrated and rinsed using microdialysis filtration units, including the Centricon^® and Microcon^® centrifugal filter devices. As an alternative to microdialysis filtration, we present an optimized method for using NucleoSpin^® XS silica columns to concentrate and clean-up aqueous extracts from the organic extraction of DNA from biological samples. The method can be used with standard organic extraction and dithiothreitol (DTT)-based differential extraction methods with no modifications to these methods prior to the concentration and clean-up step. Extracts from laboratory-prepared bloodstains, saliva and semen stains have been successfully amplified with both qPCR and STR assays. Finally, the total time to process a set of samples with the NucleoSpin^® XS column is approximately 30 min vs. approximately 1.5 h with the Centricon^® YM-100 filter device.     

Characteristics of electrically injured skin from human hand tissue samples using Fourier transform infrared microspectroscopy

This technical note describes a method for distinguishing normal skin tissue samples from those electrically injured by Fourier transform infrared microspectroscopy (FTIR MSP). Furthermore, the infrared spectral features of electrically injured cells and tissues were evaluated to identify molecular changes in epidermal cells. In the present study, 20 human hand tissue samples were evaluated macroscopically and histopathologically. The electrically injured skin samples were subdivided into 2 regions [normal cell regions (NCRs) and polarized cell regions (PCRs)] and 14 major spectral absorption bands were selected. The spectral results showed that the band absorbance at 1080, 1126, 1172, 1242, 1307, 1403, 1456, 1541, 2852, 2925, 2957, 3075, and 3300 cm^− 1 increased significantly both in the stratum and non-stratum corneum of the PCRs in electrically injured skin tissues samples. No significant difference was found between normal skin and the NCR of the electrically injured skin samples. The band absorbance ratios of A₁₁₇₂/A₁₁₂₆, A₁₄₅₆/A₁₄₀₃, and A₂₉₂₅/A₂₉₅₇ were significantly increased, whereas the A₁₆₅₂/A₁₅₄₁ ratio was decreased in the PCR of the stratum corneum and non-stratum corneum. Baseline changes from 4000 to near 1737 cm^− 1 were observed in the spectra of the electrically injured skin samples, which were interpreted in terms of the pathological process involved in electrical injury. FTIR-MSP presents a useful method to provide objective spectral markers for the assisted diagnosis of electrical marks.     

Identification of Different Forms of Cocaine and Substances Used in Adulteration Using Near‐infrared Raman Spectroscopy and Infrared Absorption Spectroscopy

Identification of cocaine and subsequent quantification immediately after seizure are problems for the police in developing countries such as Brazil. This work proposes a comparison between the Raman and FT‐IR techniques as methods to identify cocaine, the adulterants used to increase volume, and possible degradation products in samples seized by the police. Near‐infrared Raman spectra (785 nm excitation, 10 sec exposure time) and FT‐IR‐ATR spectra were obtained from different samples of street cocaine and some substances commonly used as adulterants. Freebase powder, hydrochloride powder, and crack rock can be distinguished by both Raman and FT‐IR spectroscopies, revealing differences in their chemical structure. Most of the samples showed characteristic peaks of degradation products such as benzoylecgonine and benzoic acid, and some presented evidence of adulteration with aluminum sulfate and sodium carbonate. Raman spectroscopy is better than FT‐IR for identifying benzoic acid and inorganic adulterants in cocaine.     

Counterfeit Adderall Containing Aceclofenac from Internet Pharmacies

A nontargeted approach based on liquid chromatography equipped with a quadrupole time‐of‐flight mass detector (LC‐MS Q‐TOF) joined to nuclear magnetic resonance (NMR) analysis allowed rapid identification and quantification of the anti‐inflammatory drug aceclofenac in illegal Adderall tablets. The largest chromatographic peak had m/z = 354.030 and m/z = 376.012 matching, respectively, the ionic structures (M + H)⁺ and (M + Na)⁺ of a molecule M. The accurate mass data generated the molecular formula C₁₆H₁₃Cl₂NO₄. A screening of the pharmaceutical active substances having that molecular formula together with the MS/MS fragmentation pattern suggested aceclofenac. Aceclofenac structure was unambiguously confirmed by ¹H and ¹³C NMR experiments. The aceclofenac content was 90 mg/tablet (RSD 2%) as detected by quantitative NMR. Information on the identity and content of illegal drugs is required for legal purposes; it supports in evaluating the effective impact on users safety, and it is useful for control laboratories using a targeted approach in their analytical activities.     

Corrosion behaviour of four handguns in aqueous environments: Corrosion product characterization and effects on estimating the time since deposition

When a firearm has been disposed of in a body of water and becomes corroded, its appearance is altered and determining a time-since-immersion may be of import to the investigation. Therefore, in this study, the corrosion and mass loss of four handgun slides over a period of 180 days were examined. Solid-state characterization of the metals and their corrosion products via SEM/EDX and powder X-ray Diffraction (pXRD) was performed. The pXRDs were analyzed against the NIST Powder Diffraction Database to determine the crystalline phases. Filings from the SS416 standard, Llama and Ruger handgun slide predominantly consisted of iron alloys. After 180-days in solution, pXRD indicated that the adherent corrosion products consisted of 1) γ-FeOOH and 2) iron oxide (Fe₃O₄ or Fe₂O₃). Additionally, pXRD analysis indicated that the adherent corrosion products of the SS416 standard also consisted of CrO₃. Metal filings from the Raven and Jennings handgun slides were a mixture of iron–nickel–zinc and EDX and pXRD analyses of the corrosion products, when submersed in deionized water, indicated that the products consisted of: 1) γ-FeOOH, 2) iron oxide (Fe₃O₄ or Fe₂O₃), and 3) ZnFe₂O₄ or ZnO; where the Jennings adherent rust contained ZnFe₂O₄ and the Raven adherent rust contained ZnO. Further, pXRD of the corrosion products from these alloys, when submersed in 25 PSU (Practical Salinity Unit) solution, indicated that the products consisted of: 1) ZnO, 2) Zn(OH)₂, 3) α-Ni(OH)₂, and 4) NaCl.The data thus indicated that both metal composition and the presence of chloride ions had significant impacts on rates and products of corrosion and suggest that the presence of Cl^? changes not only the rate of corrosion, but also the corroding species itself. While mechanisms and rates of the chloride driven corrosion processes offer explanations as to the different oxides and hydroxides observed between immersion conditions, they do not offer an explanation for the differences observed between handguns. Therefore, utilizing a general approach where surface area coverage of corrosion products is the sole consideration is not sufficient to determine time-since-immersion. Attempts to determine a time-since-immersion would require a priori knowledge of the mechanism of corrosion for a given metal mixture within a specified environment. The results described herein give indications as to the possible corrosion mechanism driving the process in high and low Cl^? environments and show the necessity of including the metal composition, rust composition and ion concentration in any models that attempt to elucidate the time-since-immersion of handguns for forensic applications.