Microtrace’s Range of Analytical Experience on Display at Inter/Micro 2023
Next week, microscopists from around the world will gather in Chicago for Inter/Micro 2023- the premier international microscopy conference. Ten Microtrace scientists will present papers during the symposium, which runs from Tuesday, June 13th through Friday, June 16th. The Microtrace talks cover topics including art, biological fluids, botanical materials, soils, fibers, paint, residues, and inks. The papers also cover analytical methods spanning light and electron microscopy (SEM/EDS), fluorescence microscopy, infrared microspectroscopy, energy dispersive X-ray spectroscopy, Raman microspectroscopy, and microchemistry. This breadth of topics illustrates the versatility of our approach and the range of our laboratory’s experience and expertise.
Microtrace talks include:
- Devil in the Details: Attributing Significance to Minor Analytical Data in a Forensic Comparison (Christopher Palenik, Ph.D.)
- Collecting, Analyzing, and Enjoying Chemical and Alchemical Art (Skip Palenik)
- Investigating the Utility of Novel Techniques for the Forensic Characterization and Comparison of Surficial Soils (Jack Hietpas, Ph.D.)
- The Examination of Stomach Contents in a Suspected Suicide (Jason Beckert, M.S)
- Microscopy and Microanalysis of Solution Dyed Fibers (Kelly Brinsko Beckert, M.S.)
- Is it a Van Gogh? Microanalysis of Pigments to Establish Artwork Provenance (Katie M. White, M.S)
- A Tale of Two Residues: How Thoughtful Curation of Reference Materials Aid in Unknown Identifications (Otyllia Abraham, M.S.)
- Developing Automated Mineral Identification by SEM-EDS for Forensic Laboratories (Ethan Groves)
- Do You Feel Lucky? Characterization of Shavings from Lottery Scratch Tickets (Brendan Nytes)
- Soil Preparation for Forensic Research and Analysis (Liam O’Callaghan)
Research presentations given during the first two days will cover techniques and instrumentation, environmental and industrial microscopy, and forensic and chemical microscopy.
Since its beginning in 1948, Inter/Micro has grown to attract microscopists, both amateur and professional, from all areas of light and electron microscopy. Recognized internationally, this meeting is now held every year in Chicago and continues to be sponsored and hosted by McCrone Research Institute.
The first Microscopy Symposium on Electron and Light Microscopy was developed by Walter C. McCrone (light microscopist in chemistry) and Charles Tufts (electron microscopist in physics) and was held June 10-12, 1948 at the Stevens Hotel, now the Hilton Chicago. The Inter/Micro symposia are believed to be the very first meetings to gather top people in light and electron microscopy together to discuss very small particles, including the range of ultrafine particles that are commonly referred to today as “nanoparticles.”
More details about the conference can be found here.
Devil in the Details: Attributing Significance to Minor Analytical Data in a Forensic Comparison
Christopher S. Palenik — Microtrace LLC
Forensic trace evidence comparisons are generally based upon multiple lines of analytical data that are used to determine if a sample is consistent or inconsistent with a suspected source. In the reporting phase of the analysis, this multifaceted dataset is typically condensed into a single sentence conclusion. For example, a conclusion may read, “Items Q and K are consistent by color, texture, and composition.” This generic conclusion, or a similar statement, can be found in reports based on materials as disparate as fibers, paint, and soil, and the conclusion is often, if not typically, presented without further discussion or documentation (e.g., images, spectra, data).
While superficially, such conclusions are simplified to a single, apparently, definitive answer, a critical review of the underlying data often shows a more complex story. Through examples, this talk will illustrate how recognizing and exploring the actual significance of underlying microanalytical data can lead to more nuanced findings. In some cases, careful review will disclose that the analytical work is actually quite cursory and less probative than implied, raising questions about the significance of a conclusion. In still other cases, these reviews have identified analytical differences of unknown significance. When the opportunity arises to explore and account for these differences through further analysis, we have found associations turn to eliminations and other instances where an association becomes more significant than originally implied. Such reviews require a critical look at the original raw data; a strong, fundamental understanding of the trace materials themselves; the preparation methods employed; and analytical approaches used to generate them. While such efforts are time consuming, they can lead to deeper insights into the significance of trace evidence evaluations.
The Examination of Stomach Contents in a Suspected Suicide
Jason Beckert — Microtrace LLC
This presentation will discuss a case study involving the examination of the stomach contents of an individual suspected of committing suicide. The sample was submitted to our laboratory by a medical examiner who recognized the presence of some foreign material during an autopsy. He wanted to know if this material, ingested shortly prior to the decedent’s demise, could be related to the cause of death. Our analysis focused on the identification of this unknown material that we determined to be leaves and seeds from a yew (Taxus) plant. Yew plants, native to many regions in the Northern Hemisphere, are also commonly used in landscaping and are known to contain poisonous alkaloids. This presentation will also discuss the historical usage of yew plants as agents to facilitate suicide and homicidal poisonings.
Soil Preparation for Forensic Research and Analysis
Liam O’Callaghan (presenting author), Ethan Groves, Jack Hietpas, Skip Palenik, and Christopher S. Palenik — Microtrace LLC
The analysis of soil for forensic purposes can include a complex series of analyses that can include geological, biological, and anthropogenic fractions of a sample. The initial steps of this process include documenting, sieving, and separating a soil into fractions that can be subjected to further analysis. As part of an extensive research project spanning several hundred soil samples, a preparation scheme modified from Skip Palenik’s technique for microscopical soil examination has been adopted to isolate various size and density fractions of the mineral component. This talk will provide an overview of this process and the challenges encountered in processing soils from a range of depositional environments. A qualitative overview of the resulting fractions and comparisons back to the original samples will be presented.
Investigating the Utility of Novel Techniques for the Forensic Characterization and Comparison of Surficial Soils
Jack Hietpas (presenting author), Ethan Groves, Liam O’Callaghan, Christopher S. Palenik, and Skip Palenik — Microtrace LLC
Geological materials, such as soil and dust, are ubiquitous and often inadvertently transferred to people and objects during criminal events, unfortunately, they are one of the most underutilized forms of trace evidence. The limited use of this form of physical evidence stems from the need for highly specialized knowledge to analyze and interpret soil evidence. However, when properly analyzed, it can be a very powerful form of physical evidence to establish or refute linkages between people, places, and objects. Forensic geologists use a range of particle-based analytical approaches to characterize the organic and inorganic components of soils to perform sample-to-sample (K-Q) comparisons. This presentation will discuss aspects of a large-scale research project that is currently investigating the potential value added from two new methods for the forensic examination of soil: 1) SEM-EDS based routine for high-throughput identification and quantitation of soil minerals, and 2) DNA characterization of the accompanying biological taxa. These methods will be assessed by characterizing 180 surficial soil samples collected from the three primary physiographic regions of North Carolina. These proposed methods may provide quantitative and objective metrics for forensic soil analysis and its interpretation.
Is it a Van Gogh? Microanalysis of Pigments to Establish Artwork Provenance
Katie M. White (presenting author) and Christopher S. Palenik — Microtrace LLC
As you’re walking through the thrift store or browsing an estate sale, a painting catches your eye and you wonder: could this be the lost work of a famous artist? For the curious art collector, analytical testing of the work can provide factual evidence that can help to establish provenance and lend support to potential claims. In the case of well-known artists, their pigment palette has often been studied and reported in the literature. If this information is not known, pigment identification can help to constrain the timeframe in which the work may have been created. Given the potential value of some artworks, it is imperative that the analytical methods chosen provide confident results, while also being minimally destructive.
This presentation emphasizes the valuable information that can be derived from a small particle of paint, with case examples used to illustrate the type of information that can be obtained. Polarized light microscopy, Fourier transform infrared microspectroscopy, and energy-dispersive X-ray spectroscopy each contribute to the pigment identity and ultimate interpretation.
Do You Feel Lucky? Characterization of Shavings from Lottery Scratch Tickets
Brendan Nytes — Microtrace LLC
This talk stemmed from an unknown material that was submitted to our laboratory for analysis. The sample was described as “metal shavings” and was suspected to be related to illegal drug activity. The substance was initially recognized during a visual examination. The visual identification was later confirmed through a combination of microanalysis and scientific literature. This talk will discuss the case, our approach to this identification, and the analytical characteristics of various scratch-off tickets.
Microscopy and Microanalysis of Solution Dyed Fibers
Kelly Brinsko Beckert (presenting author), Otyllia Abraham, Ethan Groves, Brendan Nytes, Christopher S. Palenik, and Skip Palenik — Microtrace, LLC
The color of a fiber is an important and distinguishing feature exploited by fiber analysts throughout the various stages of a forensic fiber comparison. This includes not only microscopical examinations, but also microanalytical techniques to identify the colorants (in addition to the fiber-forming polymers). Our current research is focused on solution dyed (i.e., pigmented) fibers, which are colored by the addition of insoluble pigment to the liquid polymer prior to extrusion. Solution dyed fibers are becoming increasingly common due to a variety of factors, including their ability to withstand harsh cleaning agents, inherent resistance to fading, and environmentally friendly manufacturing methods. The number and colors of pigments utilized in a given fiber, their identity, particle size, and optical properties represent unexploited properties that can be used to evaluate fiber associations or provide investigative information during a fiber analysis. However, there have been no systematic studies of pigmented fibers, and therefore, no practical guidance is available to the bench-level analyst to identify, characterize, or interpret pigmented fiber evidence in forensic fiber cases.
To address this knowledge gap, a systematic study of 225 solution dyed fiber samples was undertaken. The selected fiber samples span major manufacturers, include various applications of solution dyed fibers, and represent the variety of colors and polymers that are produced. This presentation summarizes the results obtained through polarized light, oil immersion, and fluorescence microscopy. Analysis of this expansive dataset will be presented to explore and summarize the microscopical observations. This will include data concerning the number of pigment types detected within a given fiber, as well as enumerations of the trends in color, morphology, and fluorescence characteristics of individual pigment grains as a function of polymer and color. Initial insights related to pigment identification from bulk elemental analysis by energy-dispersive X-ray spectroscopy, microspectrophotometry, and Raman microspectroscopy of the pigments will also be discussed.
A Tale of Two Residues: How Thoughtful Curation of Reference Materials Aid in Unknown Identifications
Otyllia Abraham — Microtrace, LLC
Chemical residues are a class of contaminants that can be found on a number of surfaces or products and in various forms such as films, discolorations, and collections of particles. The presence of these residues can result in consumer complaints, as well as failed quality assessments due to contaminated equipment or product batch rejections. The identification of a residue sample can help industry clients prevent recurrence when a source of the unknown residue, or the method of formation, can be determined.
Residues represent a challenging subset of samples due to a combination of factors, including: 1) the possibility of multiple components, 2) the matrix on which they are received, 3) the fleeting nature of some deposits, and 4) the interpretation of results to elucidate a potential source. Sample isolation and analysis is contingent on the matrix on which the residue is received and the nature of the residue itself. In order to fully characterize a residue, a suite of microscopical examination and orthogonal instrumental analyses are often necessary. Due to the complex nature of residue analyses, the determination of an origin is largely dependent on scientific interpretation of the components identified through microscopical examination and instrumental analyses. Interpretation of a residue containing multiple components is aided significantly by a knowledge of potential sources that may be used within a facility, such as detergents or lubricants. While a surficial knowledge of such sources may be gleaned through their Safety Data Sheets, the in-house analysis of these materials considerably increases the potential for a source determination.
This presentation explores two residue case studies and how the curation of common industrial detergent reference materials directly aided in a source determination.
Developing Automated Mineral Identification by SEM-EDS for Forensic Laboratories
Ethan Groves (presenting author), Jack Hietpas, and Christopher S. Palenik — Microtrace LLC
Despite its ubiquity, soil remains one of the most underexploited classes of physical trace evidence. This stems from a combination of a general knowledge gap of the probative value of soil evidence to link physical objects or people to locations and, a lack of training for analysts to conduct the often particle-based characterizations of minute amounts of soil. Automated mineral identification using scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS) coupled with R, an open-source statistical software package, provides a method that utilizes instrumentation and expertise that already exists in most forensic laboratories. Further, this method can provide quantitative compositional and mineral-count information to aid in the characterization and comparison of soil evidence.
This presentation discusses the analysis of several hundred specimens from Microtrace LLC’s mineral reference collection to evaluate, test, and optimize the various aspects of the method. Topics include sample preparation methods, spectral collection time, adjustment of instrument operation conditions, post-processing, evaluation of multiple search algorithms, and initial interpretations of the results from real-world soil samples.
Collecting, Analyzing, and Enjoying Chemical and Alchemical Art
Skip Palenik — Microtrace LLC
The presenter has been interested in paintings depicting chemists and alchemists1 since admiring the black and white picture of an “alchemist in his laboratory,” which served as the front piece of the booklet of instructions accompanying his second chemistry set. As a young adult, I saw for the first time, a large color print of the painting from which that picture had been taken and could not believe how beautiful it was to behold for the first time, as the artist had intended, in terms of size and color. No wonder! It had originally been painted for the Hercules Powder Company’s calendar in 1937 by N.C. Wyeth.
This presentation will follow the author’s acquisition of certain paintings over time, beginning with the collection of prints, which grew into commissioned reproductions of admired works, and finally into the acquisition of signed original paintings, slowly and over the years, as funds permitted. The artworks to be shown will be accompanied by notes on the artists who painted them, some thoughts on the personal enjoyment of analyzing their pigments, media, and supports, as well as learning what they reveal by IR and X-ray imaging. Included is commentary on the surprises and creative inspiration that beautiful images provide while working in the laboratory to solve our clients’ problems.
1Paintings of microscopists and microchemists are much harder to come by, but that is another story.