Inter/Micro 2025

Next week, microscopists from around the world will gather in Chicago for Inter/Micro 2025- the premier international microscopy conference. Eight Microtrace scientists will present papers during the symposium, which runs from Tuesday, June 10th through Friday, June 13th. The Microtrace talks cover topics including art, airbags, biological fluids, blood, drugs, paints, pigments, soils, fibers, microplastics, and pharmaceuticals. The papers also cover analytical methods spanning light and electron microscopy (SEM), infrared microspectroscopy, energy dispersive X-ray spectroscopy (EDS), Raman microspectroscopy, fluorescence miscroscopy, 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:

• A Microanalytical Approach to Fine Art Authentication ( Christopher Palenik)
• No Two Way Transfers About It (Jason C. Beckert)
• Left in the Dust:  A Forensic Case Study Involving the Potential Transfer of Fibers and Airbag Particles in a Crash (Kelly Beckert)
• Triumphs and tribulations in the sourcing of paint smears (Ethan Groves)
• Some Useful Accessories for the Analytical Microscopist (Skip Palenik)
• A Bloody Good Time: Investigating the impact of controlled substances on human-specific immunochromatographic blood tests (Otyllia Vercelletto)
• What Can It Pea? Identifying and Sourcing Foreign Contaminants Found in Food Products (Briana Alarcon)
• Identification of Pigments in Solution Dyed Fibers via Raman Microspectroscopy (Jared Estevanes)

Research presentations given during the first two days will cover techniques and instrumentation, environmental and industrial microscopy, and forensic and chemical microscopy.

All abstracts for Inter/Micro presentations can be found here.

Inter/Micro

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.

Abstracts

A Microanalytical Approach to Fine Art Authentication Palenik, Christopher

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 macroscopic and stereomicroscopic examination of the object.  This typically includes a study using illumination that spans the ultraviolet (short wave and long wave), 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 is 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 system (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 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 over the past three-plus decades, which have included works attributed to artists that include Monet, Picasso, Constable, Calder, Dali, Kandinsky, Klein, and Pollock; antiquities that span millennia, and collectibles attributed to Ruth, “Shoeless” Joe Jackson, Mantle, among many others.

No Two Way Transfers About It Beckert, Jason

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.

Left in the Dust:  A Forensic Case Study Involving the Potential Transfer of Fibers and Airbag Particles in a Crash Beckert, Kelly

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 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.

Triumphs and tribulations in the sourcing of paint smears Groves, Ethan

Forensic paint analysis typically involves characterization and comparison of miniscule samples, which, given their size, limit the utility of many industrial protocols and procedures for paint analysis. Evidence in many of these cases consists of transfers or smears of paint from one source to another, which compounds their difficulty through the potential mingling of components from several layers or multiple sources. In such instances, a determination of stratigraphy (layer sequencing) or obtaining data from a pure (non-mixed) sample may not be possible. However, despite these challenges, careful and thoughtful analysis of paint smears can often still provide sufficient data to support a probative result.

The case examples presented will highlight a range of experiences and challenges encountered in comparison and sourcing of paint smears. They intend to demonstrate the value that detailed analysis of paint smears can provide on this often small and complicated type of trace evidence.

Some Useful Accessories for the Analytical Microscopist Palenik, Skip

In the course of more than 60 years in the practice of analytical microscopy, the presenter has found use for or value in a number of accessories that have, over time, become essential to his work as a practicing chemical/forensic microscopist.  This talk will illustrate some of these items, describe their use, explain how they found their way into my laboratory and how they helped in certain cases or in helping to master particular subject matter that is not generally available.

A Bloody Good Time: Investigating the impact of controlled substances on human-specific immunochromatographic blood tests Vercelletto, Otyllia

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 origins. 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 heamoglobin 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.

Identification of Pigments in Solution Dyed Fibers via Raman Microspectroscopy Jared Estevanes PhD*, Kelly Brinsko Beckert MS, Ethan Groves BS, and Christopher Samuel Palenik PhD

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. (2024)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. The fibers were prepared for analysis by utilizing a micro-roller, in order to retain applicability within trace evidence crime lab sections. 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.

What Can It Pea? Identifying and Sourcing Foreign Contaminants Found in Food Products Alarcon, Briana

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, 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.

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