Abstracts and Presentation Schedule
Abstracts are listed in order of author presentations for Tuesday, June 10 and Wednesday, June 11. The presentation schedule is subject to change; check this page regularly for updates.
TUESDAY, JUNE 10
MORNING
Books that Led the Way — Video Presentation
Brian J. Ford
Some books from my library reveal the story of the microscope, from Robert Hooke’s Micrographia (1665) to Victorian-era publications. Highlight like Henry Baker’s The Microscope Made Easy (1743) and John Quekett’s A Practical Treatise (1848) popularized microscopy though there was a “silent century” between, when microscopy stagnated, followed by a surge in public interest, driven by books like J.G. Wood’s Common Objects of the Microscope (1861). Such texts, with their detailed illustrations, reflect microscopy’s scientific and cultural impact in a journey from curiosity to rigorous science.
“Pretermit Inverse Condemnation” Sounds Impressive! (but XRD and Heavy Minerals Provide the “True” Answer at a Contested Aquaculture Site)
Wayne Isphording — Department of Earth Sciences, University of South Alabama
Commercial aquaculture in coastal zones of the United States generates an annual seafood production valued at over 1.5 billion dollars and supports nearly 1.7 million jobs. Inevitably, however, conflicts and interferences have arisen with other commercial and coastal projects that are being carried out by various state and private entities. For example, in Eastern Mississippi Sound, Alabama, mud from a dredging operation associated with a state marsh-restoration project, allegedly has impacted a private, planted reef by “smothering” the protection guaranteed by the Eminent Domain Liability clause in the juvenile oyster spat. The plaintiff demanded “damages,” citing U.S. Constitution! The defense’s expert, however, provided ocean current flow and Wind-Rose current directional data in the Sound from a recent NOAA investigation that, combined with detailed Heavy Mineral and XRD analyses, clearly identified the true source of sediments damaging the reef as resulting from discharge from a stream located in close proximity to the reef, rather than from a dredge, operating several miles distant from the reef site. This evidence, when reviewed by the plaintiff, quickly produced a “modest,” out-of-court settlement on the first day of the trial!
Portraits of the Great Microscopists: An Inter/Micro History Event
Joseph Barabe — Barabe & Associates LLC
Between 1998 and 2003, Joe Barabe photographed Inter/Micro attendees as part of his Great Microscopist series. Recently, it was recommended that he share the portraits taken at that time with the current attendees of this international conference and possibly re-photograph those that continue to participate, as well as photograph new attendees. These portraits can be used without restrictions and without cost. Joe will give a short talk on his motives and methods and will be available during breaks for your portrait.
Use of Nomarski Differential Interference Contrast (DIC) Microscopy in Failure Analysis
Andrew A. “Tony” Havics — pH2 LLC
Nomarski Differential Interference Contrast (DIC) Microscopy was invented by Georges Nomarski in the mid-1950s and is used to image specimens that contain little or no optical contrast when viewed using traditional brightfield microscopy. In transmitted mode, DIC can provide valuable information about polymers and other transparent specimens (including replicas) such as shearing orientation, inhomogeneous melts, voids, welding characteristics, residual stress, adhesion failures, refractive index determination, etc. In reflected mode, DIC allows comparisons of materials phases not otherwise revealed (without etching), expression of surface topography, finding inhomogeneities in integrated circuits, optical components, evaluating growth in etched polymers, melt and flow effects in films, co-polymer morphology, and phases in films and foams, etc.
A Bloody Good Time: Investigating the Impact of Controlled Substances on Human-specific Immunochromatographic Blood Tests
Otyllia Vercelletto — Microtrace LLC
The identification of blood on forensic exhibits is often accomplished by either microscopical examination and microchemical methods or with immunochromatographic blood tests. Both techniques are highly sensitive, however, microscopical methods of identification do not readily distinguish between blood of human or animal origin. As such, the use of a human-specific immunochromatographic test is often necessitated to confirm this origin.
Commercially available assays of this nature detect specific components present in human blood through the interaction between antigens and antibodies. Samples applied to the test strips migrate via capillary action and the analytes bind to immobilized antibodies, providing a visible signal in the form of a colored line. The target analytes generally include human hemoglobin and glycophorin A.
While these assays have historically demonstrated extreme sensitivity and selectivity, a real-word case revealed an unlikely, yet major, source of interference in the test’s sensitivity: methamphetamine HCl. This presentation will provide an overview of the presumptive and confirmatory tests for the presence of human blood. Additionally, the aforementioned case study will be discussed in conjunction with further in-house research regarding the impacts of common controlled substances on the sensitivity of a commercially available human-specific immunochromatographic blood test.
Microchemical Identification of Trace Amounts of Potassium and Iodide in a Drug Product
Jan Burmeister (presenting author) — Chemie AG, Berlin, Germany
Martin Dähnrich — Chemie AG, Berlin, Germany
The identity of iodide ions was tested for years using HPLC in the form of ion-pair chromatography on potassium iodide tablets containing either 100 µg or 200 µg of iodide per single tablet. The equivalence of peak retention times was used as the criterion for decision-making. The identity of potassium ions was confirmed through the use of atomic absorption spectroscopy.
In response to a request from a national drug authority, an alternative approach for these two identity tests was developed and validated using classical precipitation reactions for potassium and iodide, which were adapted to a microchemical scale. Potassium was identified in the form of K3[Co(NO2)6] or potassium hexanitritocobaltate(III), while iodide was identified in the form of PbI2, which is lead iodide. A special focus was set on a selective enrichment procedure for the trace amounts of both ions present in the drug product.
TUESDAY AFTERNOON
No Two Way Transfers About It
Jason C. Beckert — Microtrace LLC
This presentation will focus on the role that trace evidence played in an accident reconstruction case. With no witnesses to the event in question and incomplete digital data, trace evidence played a crucial role in the reconstruction effort. The presentation will focus on how the recognition, isolation, analysis, and interpretation of trace evidence from numerous objects were used to reconstruct the circumstances upon which the accident occurred.
Applying Microscopes and Microscopical Principles in Plastics Manufacturing
Kevin Brady — K A Brady & Associates LLC
Every industry has challenges to quality and productivity. There are errors to be corrected and mysteries to be solved. Producing high quality plastic films for use in medical, electronics, and consumer hygiene products, can sometimes require applying investigative principles not unlike a detective in a Sherlock Holmes story or an Edmond Locard case. In this presentation, I will discuss some of my more challenging cases and the how the microscope and microanalysis techniques met the challenge.
The Controversy of Determining Quantification in Bamboo and Chemical Wood Pulps
Walter J. Rantanen — SGS-IGS Testing
There have been some claims that the paper fiber analysis method is not able to give accurate percentages of bamboo fiber content when mixed with hardwood or softwood kraft pulps. A study was carried out using several analysts and know mixtures of bamboo and chemical wood pulps. The testing used light microscopy with staining techniques to examine the anatomical differences of the pulps. The fiber counts and recommended weight factors were used to quantify the percentages and the results were examined with statistical analysis.
A Microanalytical Approach to Fine Art Authentication
Christopher Palenik — Microtrace LLC
The scientific analysis of art, antiquities, and collectibles offers an orthogonal approach to stylistic examinations, signature analyses, and historical research. When conducted rigorously and reported in a transparent manner, scientific analyses hold the potential to provide unequivocal factual information that can, in many instances, provide additional support or clarification for questioned, controversial, or disputed works.
Based upon decades of experience working with a wide range of media, our laboratory has developed an approach that is tailored to the specific object, its properties, and our client’s questions. Be it an oil painting, large format outdoor sculpture, or a signed baseball bat, a microanalytical approach can contribute a wealth of information. While not every method is applicable to every object, our approach typically begins with an overall macroscopical and stereomicroscopical examination of the object. This typically includes a study using illumination that spans the ultraviolet (shortwave and longwave), visible, and near-infrared regions of the spectrum as well as x-rays (radiography). These analyses have the potential to provide both analytical information and guidance in identifying areas upon which to focus further analyses.
These examinations are typically followed by the collection of microscopic samples. While in situ micro-analysis is possible in some circumstances, the collection of microscopic samples typically permits a deeper exploration of the materials comprising a work. Initially, microscopic samples are studied by a combination of polarized light and fluorescence microscopy, which can provide information about the structure of a sample, in the cross section preparations, as well as the variety and optical properties of the components that are utilized, e.g., colorants and fillers. Infrared and Raman microspectroscopy, as well as elemental analysis by energy dispersive x-ray spectroscopy in a scanning electron microscopy (major and minor elements), and x-ray fluorescence (trace elements) provide information about the chemistry and elemental composition of pigments, binders, and other components of a sample. Other methods such as pyrolysis-GC/MS, cathodoluminescence, electron backscatter diffraction, and transmission electron microscopy can provide further information about the composition and characteristics of a sample.
While appropriate instrumentation is critical to the process, the intangible elements of an analysis that can include appropriate reference materials, sampling approaches, and sample preparation techniques, knowledge of and selection of appropriate analytical conditions, and data interpretation are just as important to the process of a rigorous examination. The approach and experiences that will be discussed in this presentation are based upon the analysis of fine art and collectibles seen in our laboratory for more than three decades, which have included works attributed to artists that include Monet, Picasso, Constable, Calder, Dali, Kandinsky, Klein, and Pollock; antiquities that span millennia; and sports collectibles attributed to Ruth, “Shoeless” Joe Jackson, Mantle, and many others.
Based upon decades of experience working with a wide range of media, our laboratory has developed an approach that is tailored to the specific object, its properties, and our client’s questions. Be it an oil painting, large format outdoor sculpture, or a signed baseball bat, a microanalytical approach can contribute a wealth of information. While not every method is applicable to every object, our approach typically begins with an overall macroscopical and stereomicroscopical examination of the object. This typically includes a study using illumination that spans the ultraviolet (shortwave and longwave), visible, and near-infrared regions of the spectrum as well as x-rays (radiography). These analyses have the potential to provide both analytical information and guidance in identifying areas upon which to focus further analyses.
These examinations are typically followed by the collection of microscopic samples. While in situ micro-analysis is possible in some circumstances, the collection of microscopic samples typically permits a deeper exploration of the materials comprising a work. Initially, microscopic samples are studied by a combination of polarized light and fluorescence microscopy, which can provide information about the structure of a sample, in the cross section preparations, as well as the variety and optical properties of the components that are utilized, e.g., colorants and fillers. Infrared and Raman microspectroscopy, as well as elemental analysis by energy dispersive x-ray spectroscopy in a scanning electron microscopy (major and minor elements), and x-ray fluorescence (trace elements) provide information about the chemistry and elemental composition of pigments, binders, and other components of a sample. Other methods such as pyrolysis-GC/MS, cathodoluminescence, electron backscatter diffraction, and transmission electron microscopy can provide further information about the composition and characteristics of a sample.
While appropriate instrumentation is critical to the process, the intangible elements of an analysis that can include appropriate reference materials, sampling approaches, and sample preparation techniques, knowledge of and selection of appropriate analytical conditions, and data interpretation are just as important to the process of a rigorous examination. The approach and experiences that will be discussed in this presentation are based upon the analysis of fine art and collectibles seen in our laboratory for more than three decades, which have included works attributed to artists that include Monet, Picasso, Constable, Calder, Dali, Kandinsky, Klein, and Pollock; antiquities that span millennia; and sports collectibles attributed to Ruth, “Shoeless” Joe Jackson, Mantle, and many others.
Authentication Analysis of a Tani Buncho Scroll: A PLM Tour through Japanese Traditional Materials
Joseph Barabe — Barabe & Associates LLC
The grandparents of my client had received a hanging scroll painting by the highly regarded Japanese artist Tani Buncho (1763–1840) as a wedding present. In spite of a reasonable provenance, she was concerned about the authenticity of the work. The analysis of the materials was actually a joy, as in my work I rarely see works made in this classical Japanese traditional manner. Yet, the project was not without challenges: many important colors were available only as thin layers over the unprimed fabric substrate, so the sparse, dry paint particles were difficult to gather and sample collection required some innovative techniques. While polarized light microscopy (PLM) was sufficient for most of the samples, other analytical modalities were necessary to complete the analysis.
The Last Pollock
Nicholas Petraco
This paper presents the story of a long journey to authentication for an untitled painting, claimed to be by Jackson Pollock’s hand. The painting known as “Red, Black, and Silver" (RBS) measures 60.9 cm × 50.8 cm and is an abstract expressionist oil on canvas board painting said to have been created in the summer of 1956, weeks before Pollock was killed in a tragic automobile accident. RBS has been the subject of a long-standing disagreement between the artist's girlfriend, Ruth Felicity Kligman, and his estranged wife, Lee Krasner. Ms. Kligman claims that she saw Pollock painting RBS in the summer of 1956 on her used canvas board and that when Pollock completed the work, he gave the painting to her. Mrs. Pollock asserted that the painting was a fake. Lee Krasner died on June 19, 1984. In the early 1990s, Ruth Kligman presented RBS to the newly created 2nd Pollock-Krasner Authentication Board Committee. At that time, the committee offered to place RBS into Pollock’s Supplement Catalogue Raisonné, published in 1995, in a section listing works needing more study. Kligman rejected the offer. After Ms. Kligman died in 2010, her estate trustees requested a full forensic assessment of RBS also presented in this paper.
WEDNESDAY, JUNE 12
MORNING
Left in the Dust: A Forensic Case Study Involving the Potential Transfer of Fibers and Airbag Particles in a Crash
Kelly Brinsko Beckert — Microtrace LLC
In the aftermath of a deadly car accident, the suspected driver denied being behind the wheel. The driver’s seatbelt and airbag were collected, along with clothing worn by the suspect, and the items were analyzed for evidence of any transfer between them. This included four different types of fibers from one garment, airbag particles, and metal fragments, each subjected to an extensive forensic analysis and comparison.
Dust and debris isolated from the seatbelt and airbag were examined for fibers similar to those comprising the fleece jacket worn by the suspect. The fibers were compared to known fibers using polarized light microscopy (PLM), fluorescence microscopy,microspectrophotometry (MSP), and Fourier-transform infrared microspectroscopy (µ-FTIR). The results of these comparisons will be discussed, along with an additional circumstance surrounding the case that emphasizes the importance of communication between scientists and investigators.
Particulate matter collected from the airbag interior and from the suspect’s fleece were analyzed in a scanning electron microscope (SEM) coupled with an energy-dispersive X-ray spectrometer (EDS) using an automated particle analysis routine. Copper-rich particles were plentiful on the known airbag, and were also detected on the fleece. However, due to the lack of distinguishing characteristics or elemental composition of these particular airbag particles, together with data from a study regarding the occurrence of copper particles in environmental dust, it could not be determined if the copper-rich particles detected on the fleece originated from the airbag or from another environmental source.
Teaching Asbestos Fiber Counting by Phase Contrast Microscopy (PCM)
Andrew A. “Tony” Havics — pH2 LLC
The use of the membrane filter technique began in earnest in the mid 1960s. In 1974, the American Conference of Governmental Industrial Hygienists (ACGIH) set a Threshold Limit Value (TLV) for asbestos in new units, fibers per cc (f/cc), specifying in a footnote that the determination was to be by the membrane filter technique. In October 1975, the Occupational Safety and Health Administration (OSHA) proposed lowering the permissible exposure limit (PEL) with subsequent monitoring of employees using the membrane filter technique by Phase Contrast Microscopy (PCM). Not long thereafter, in 1979, the United States Public Health Service-National Institute for Occupational Safety and Health (USPHS-NIOSH) Membrane Filter Method for Evaluating Airborne Asbestos Fibers was published. Along with this, came the September 1979 NIOSH course entitled “Sampling and Evaluating Airborne Asbestos Dust (582).” With the advent of the new 1926.58 Asbestos in construction regulations in 1986 came a requirement to use the OSHA Method in Appendix A (referred to as the OSHA Reference Method or ORM), requiring the membrane method as well as a requirement for analyst to have taken the NIOSH course for sampling and evaluating airborne asbestos, or an equivalent course. The 1987 Worker Protection rule in the Asbestos Hazard Emergency Response Act (AHERA) regulations also required the ORM as well as a requirement for analysts to have taken the NIOSH course for sampling and evaluating airborne asbestos, or an equivalent course. The number of courses offerings for an equivalent 582 course increased significantly in 1988, paralleling the AHERA inspector, management planner, design, worker and supervisor courses that also proliferated. Prior this time period, a lot of training took place in-house.
Beginning in 1988, I assisted with an equivalent course and in the early 1990s began teaching courses. These have varied from in-house only, to quasi-in-house, to on-site for specific companies, to typical established training providers such as the Environmental Management Institute in Indianapolis, Indiana. This includes more than 70 courses taught by me at The McCrone Research Institute in Chicago, since 1999. After multiple courses and hundreds of students, one observes teaching techniques that work and some that don’t. One develops objectives and goals. One also learns to recognize limitations in methodology and application related to training, instruction, and inherent student skill (or lack thereof). This presentation will provide an overview of the current course, lessons learned, and implications for interpretation of analytical data currently, as well as historically.
Beginning in 1988, I assisted with an equivalent course and in the early 1990s began teaching courses. These have varied from in-house only, to quasi-in-house, to on-site for specific companies, to typical established training providers such as the Environmental Management Institute in Indianapolis, Indiana. This includes more than 70 courses taught by me at The McCrone Research Institute in Chicago, since 1999. After multiple courses and hundreds of students, one observes teaching techniques that work and some that don’t. One develops objectives and goals. One also learns to recognize limitations in methodology and application related to training, instruction, and inherent student skill (or lack thereof). This presentation will provide an overview of the current course, lessons learned, and implications for interpretation of analytical data currently, as well as historically.
Sorting (Teeny) Talc from (Tiny) Chrysotile
L.A. Thomas (presenting author) and G.K. Druschel — Department of Earth Sciences, Indiana University, Indianapolis
The Food and Drug Administration has proposed a testing standard for detecting asbestos in talc products. The proposal includes the use of optical microscopy techniques, specifically Polarized Light Microcopy (PLM) and dispersion staining, to discern asbestos from talc. These techniques have long been used effectively for detecting asbestos in bulk materials. The bulk building materials typically subjected to this analysis almost always have physical, chemical, morphological, and optical properties quite distinct from the asbestos targets. In the case of chrysotile and talc, those differences shrink. Optically, the RI range of chrysotile overlaps that of talc’s alpha, especially at longer wavelengths. Physically, the smallest chrysotile particles (the minimum definition of “fibers” is 5µm long and ~ 1.7 µm wide) are of similar size as milled talc sold for consumer use. This minimum fiber size is ~3−10 times the wavelength of light used to view them; very near the limit of visibility using optical microscopy. This paper reports an examination of the factors impacting necessary precision using PLM and dispersion staining to discern chrysotile in a talc matrix at sizes near the limit of optical microscopy’s resolution. We focus on distinguishing between chrysotile and talc plates on edge, since those plates strongly resemble fibers. Sources of imprecision in assessing the RI of these materials include particle size, shape, orientation, depth in the mount, “dip angle,” and electronic system noise. Depth effects are especially pronounced in dispersion staining. We can neither change this, nor measure it, and it generates uncertainty and imprecision in assessing matching wavelength. We recommend against the use of optical microscopy techniques for discerning chrysotile from talc on this scale; they push too hard on the physics of light-matter interactions and, for low amounts of chysotile in a talc matrix, set up a statistical likelihood of false positives.
Variation of Dispersion Staining Colors Observed by Analysts with Different Experience Levels and Other Points of Variation
Thomas A. Kubic (presenting author), Michelle Miranda and Antonio Del Valle — John Jay College CUNY
According to the National Voluntary Laboratory Accreditation Program (NVLAP) asbestos accreditation checklist, NIST HB 150-3, the analyst when identifying a regulated asbestos insulation mineral must measure and document both the parallel and perpendicular refractive indices. The sample is considered positive if the mineral is asbestos form and the measured indices fall within the generally accepted ranges for the six regulated minerals (1,2). The checklist also requires that the laboratory analyst be capable of measuring the particular values employing a polarized light microscope, to within an accuracy of ± 0.004 refractive index units. Because asbestos minerals are microscopic in size, these measurements are performed by immersion methods, wherein the sample is placed in a liquid, and utilizing Becke lines, dispersion staining, or Schroeder van daKolt shadowing methods, the indices are determined.
Dispersion staining has become the most popular technique employed by these accredited laboratories, because it is easy to perform and does not require the changing of the immersion liquid to make a determination. Most labs and analysts are unaware that they could meet the regulatory agency’s requirements without the need to change refractive index liquids on their samples by not only Dispersion Staining, but employing Becke and shadowing methods.
Dr. Walter C. McCrone (3) and Dr. Shu-Chun Su (4) have published methods and data to convert the matching wavelength (λ0) to the required refractive index. Recently there have been some questions concerning the ability of individuals to correctly perform this measurement because of color-perception differences amongst individuals and the illumination employed with a specific microscope.
In this paper, we report the results obtained when individuals with different levels of dispersion staining experience (great, some, none) identify the match wavelength (λ0) on chrysotile and amosite asbestos, when different brands of immersion liquids are used and/or various microscope illumination sources are employed. Their results were compared with the matching wavelength (λ0) obtained as measured by an Ocean Optics 2000+ micro-spectrophotometer (MSP).
Dispersion staining has become the most popular technique employed by these accredited laboratories, because it is easy to perform and does not require the changing of the immersion liquid to make a determination. Most labs and analysts are unaware that they could meet the regulatory agency’s requirements without the need to change refractive index liquids on their samples by not only Dispersion Staining, but employing Becke and shadowing methods.
Dr. Walter C. McCrone (3) and Dr. Shu-Chun Su (4) have published methods and data to convert the matching wavelength (λ0) to the required refractive index. Recently there have been some questions concerning the ability of individuals to correctly perform this measurement because of color-perception differences amongst individuals and the illumination employed with a specific microscope.
In this paper, we report the results obtained when individuals with different levels of dispersion staining experience (great, some, none) identify the match wavelength (λ0) on chrysotile and amosite asbestos, when different brands of immersion liquids are used and/or various microscope illumination sources are employed. Their results were compared with the matching wavelength (λ0) obtained as measured by an Ocean Optics 2000+ micro-spectrophotometer (MSP).
1. Deer, W.A., Howie, R.A., and Zussman, J. Introduction to the Rock Forming Minerals, Longman, 1966.2. US EPA, “Test Method: Method for the Determination of Asbestos in Bulk Building Materials,” EPA/600/R-93/116, Tables 2.2 and 2.3, July, 1993.3. McCrone, W.C. “Calculation of Refractive Indices from Dispersion Staining Data,” The Microscope, 37:1, p. 49, 1989.4. Su, Shu-Chun, Rapidly and Accurately Determining Refractive Indices of Asbestos Fibers by Using Dispersion Staining Method: A Standard Operating Procedure for Bulk Asbestos Analysis by Polarized Light Microscopy, Hercules Incorporated, Wilmington, DE, January, 1996.
Identification of Pigments in Solution Dyed Fibers via Raman Microspectroscopy
Jared Estevanes (presenting author), Kelly Brinsko Beckert, Ethan Groves, and Christopher Palenik — Microtrace LLC
Solution-dyed fibers are synthetic fibers that have been colored through the introduction of insoluble pigments into the polymer before final extrusion. The market share of solution-dyed fibers is increasing; thus, their forensic relevance must be developed. This work is a continuation of Brinsko-Beckert et al. (1), which characterized pigments within a set of solution-dyed fibers based on their optical properties using polarized light microscopy and fluorescence microscopy. Here, these same fibers were analyzed via Raman microspectroscopy with the aim of identifying the various pigments used to color them. In order to retain applicability within trace evidence crime lab sections, the fibers were prepared for analysis by utilizing a micro-roller. Major challenges of analysis by Raman microspectroscopy included fluorescence and background interference from the fiber itself, however most of the pigments (as previously observed by light microscopy) could still be identified. Pigments identified in this study include commonly encountered pigments such as Pigment Blue 15 and Pigment Red 102, along with more unusual pigments such as Pigment Red 202 and Pigment Yellow 150. This study provides trace evidence examiners with a foundational methodology to exploit the capabilities of Raman microspectroscopy for the identification of solution-dyed fiber pigments within casework.
1. Brinsko Beckert K., Palenik S., Abraham O.R., Groves E., and Palenik C.S. Microscopical Recognition and Characterization of Solution Dyed Fibers. J Forensic Sci., 69, pp. 60–80, 2024; https://doi.org/10.1111/1556-4029.15423.
WEDNESDAY AFTERNOON
What Can It Pea? Identifying and Sourcing Foreign Contaminants Found in Food Products
Brianna Alarcon — Microtrace LLC
From agricultural fields to grocery store shelves, there are plenty of ways foreign contaminants can find their way onto a consumer’s dining room table. This presentation highlights the value of a multidisciplinary approach – integrating polarized light microscopy (PLM), microchemical techniques, and chemical analysis – to effectively identify a variety of alleged contaminants found in food matrices.
The findings, from two cases in particular, underscore the power of PLM and its integration in routine food forensic projects that often go overlooked when jumping to instrumental techniques immediately. Not only can these seemingly outlandish particles be identified, but in some instances, they can be characterized to the point of understanding from where they could have originated.
While the case examples represent entirely different materials, this multidisciplinary approach provided the interested parties with factual information in a timely manner, which, in turn, could be used to make informed decisions in their contamination investigations. One might say these examples are two peas in a pod.
Characterization of the Lattice Vibrations of Ammonium Nitrate in an ANFO Mixture After Authentic Explosions Using Micro-Raman Spectroscopy and Single Crystal X-Ray Diffraction
Geraldine Monjardez (presenting author), Jared Estevanes, and Nicholas Jernigan — Department of Forensic Science, College of Criminal Justice, Sam Houston State University, Huntsville, TX
Christopher Zall — Department of Chemistry, College of Science and Engineering Technology, Sam Houston State University, Huntsville, TX
This study aimed to characterize ammonium nitrate lattice vibrations in an ammonium nitrate and fuel oil mixture (ANFO) following authentic explosive events using micro-Raman spectroscopy and single-crystal X-ray diffraction (XRD). Two simulated IEDs were constructed, consisting of several different substrate materials, and exploded using ANFO as the main charge. Crystalline material was observed to be growing on several of the post-blast substrates. Microscopical examination revealed the crystalline material to have isotropic and anisotropic characteristics. Following recrystallization from water, the material was identified as ammonium nitrate. For the post-blast crystals, XRD was used to determine the unit cell parameters and crystal structure; these matched the known Phase IV [Form II] structure of ammonium nitrate, with slight but statistically significant differences from the previously published structure. Ex-situ analysis of isotropic crystalline fragments using micro-Raman determined that the lattice vibrations within the material were different than the ANFO intact reference, with the blue shifting of several bands, the emergence of new bands, and the loss of other characteristic bands. It was determined that the isotropic crystalline material observed in the post-blast residue consisted of stressed-state Phase 4 [Form II] ammonium nitrate.
Case Examples from the U.S. Postal Inspection Service Forensic Laboratory
Andrew Bowen — U.S. Postal Inspection Service
The U.S. Postal Inspection Service (USPIS) National Forensic Laboratory (NFL) is a full-service forensic laboratory located in Dulles, VA. USPIS is one of the oldest law enforcement agencies in the country, with a rich history of using forensic analysis to support their investigations. They played an important role in high profile cases ranging from the Siskiyou massacre during the attempted robbery of a Southern Pacific Railroad train in 1923 to the Unabomber investigation that concluded when a US Postal Inspector placed handcuffs on Ted Kaczynski during his arrest in 1996. Several recent case examples employing light microscopy and/or microanalytical methods will be shared. The cases were selected to illustrate the range of investigations that fall under the jurisdiction of USPIS and to demonstrate the capabilities of the NFL.