Microtrace Scientists Present on Nanoparticles at Pittcon 2018

Pittcon 2018 Conference and Expo was held in Orlando, Florida from February 26th to March 1st.

On Thursday, March 1st, Microtrace scientists Katie White and Kelly Beckert presented four posters at the conference during the National Institute of Justice’s inaugural forensic science research and development poster session. Their posters detailed aspects of Microtrace’s research into nanoparticles and other subvisible particles as trace evidence. Katie exhibited two posters on “A Forensic Study of Known Toner Particles” and “Applications of Glass Microspheres as Forensic Trace Evidence,” and Kelly presented two posters entitled “The Forensic Analysis of 3D Printer Dust Particles” and “Nanoparticles as Trace Evidence: Part I. Recognition and Collection.”

Their work on these subjects has been supported by a grant from the National Institute of Justice.



Pittcon is an annual Conference and Expo organized by the Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy. Pittcon is the world’s leading annual conference and exposition on laboratory science. It attracts attendees from industry, academia and government from over 90 countries worldwide.

Pittcon’s target audience is not just “analytical chemists,” but all laboratory scientists — anyone who identifies, quantifies, analyzes or tests the chemical or biological properties of compounds or molecules, or who manages these laboratory scientists. Having grown beyond its roots in analytical chemistry and spectroscopy, Pittcon has evolved into an event that now also serves a diverse constituency encompassing life sciences, pharmaceutical discovery and QA, food safety, environmental, bioterrorism and other emerging markets.

Their mission is to sponsor and sustain educational and charitable activities for the advancement and benefit of scientific endeavor.



A Forensic Study of Known Toner Particles

Katie M White; Christopher S Palenik, PhD

Whether we’re aware of them or not, small particles abound in the environments that surround us. Small particles may be engineered for use in manufactured products; be present in dusts generated from manmade industrial processes; or occur naturally in the environment. Some of these particles are just barely visible, while others are so small that they cannot be resolved by the human eye. These subvisible and submicron particles (nanoparticles) offer potential as forensic evidence, but are presently unexploited due to the challenges their small size present.

One example of sub-visible particles is the toner powder used in laser printers and copiers. Presently, most existing research on forensic toner analysis focuses on document examination (i.e., analysis of printed toner) rather than on trace evidence. However, toner is widely used and these small particles are easily transferred and rarely noticed. Identification of trace amounts of toner (e.g., on hands or clothing or in dust) could be used to provide investigative leads or associate them with a scene and/or victim, particularly if the particles are suggestive of a specific toner.

This poster will discuss the results from an analytical study of over 50 different toner samples. This research evaluates microscopical morphologies, observed by light microscopy and scanning electron microscopy, and chemical properties, determined by Raman spectroscopy, of the known toner samples, providing methods that can be used in the forensic laboratory to identify and classify toner particles. Analytical differences observed within the sample set, the prevalence of background toner particles in different environments, and limitations of this approach will be covered.

Applications of Glass Microspheres as Forensic Trace Evidence

Katie M White; Brendan Nytes; Christopher S Palenik, PhD

Microspheres are used in an increasing variety of applications, from personal care products to food and industrial applications. Glass microspheres represent a significant subset of the microsphere market and are encountered in cosmetics, paints, plastics, building materials, and other applications. While they are used in a variety of consumer-grade products, their size, transparency, and shape can make them difficult to find or easy to overlook. For example, in solution, an isotropic, glass microspheres may be confused with an immiscible phase. Despite such difficulties, the size range (~5–1,000 µm) and composition (glass) make them accessible and potentially useful indicators of products, activity, or associations.

This poster will cover the range of physical, optical, and elemental characteristics of reference microspheres obtained from manufacturers and the ways in which glass microspheres can be located and characterized in industrial and consumer applications, e.g., cosmetics, spackle, and polymers. When present in dust, microspheres may be encountered as free particles, where they may be the sole basis of an association, or they may be encountered in a matrix, e.g., a polymer or ceramic, where they could be used to improve the significance of an association. The results from these analyses illustrate some of the ways in which microspheres can be located, characterized, and interpreted in the context of a forensic investigation.

The Forensic Analysis of 3D Printer Dust Particles

Kelly Brinsko Beckert and Christopher S. Palenik; Microtrace, LLC

3D printers are becoming increasingly efficient and economical, and thus more widespread and easily accessible to consumers and the general public.  Previous research has documented the release of dust particles during the printing process.  However, little is known about their morphology and other characteristic features.  This study was undertaken as part of a federal research grant (NIJ Grant No. 2015-DN-BX-K033) to characterize these particles so that they may be collected, recognized, and analyzed appropriately.  Samples were collected from a variety of 3D printers, representing both consumer- and commercial-grade models.  These printers use thermoplastic filaments, typically polylactic acid (PLA) or acrylonitrile butadiene styrene (ABS), though others may be used (nylon, polyvinyl acetate, polyurethane, etc.).  Cotton or polyester-flocked swabs were used to collect dust from various surfaces within the printer chamber and surrounding areas up to 10 feet away.  Particles produced from ABS filaments are most easily recognized based on color and rounded morphology via light microscopy; FTIR spectra of the particles confirmed the identification of the ABS polymer.  Pigments and the ABS polymer matrix were also identified using Raman microspectroscopy.  Dust from PLA printers consistently contained finer, submicron sized particles (relative to background levels) that could be observed by field emission scanning electron microscopy; however, the size of the particles precluded their specific identification as PLA.  This presentation will detail the collection procedures employed to find, isolate, identify, and compare 3D printer dust particles, and a discussion of their potential applications and limitations as forensic evidence.

Nanoparticles as trace evidence:  Part I. Recognition and collection

Kelly Brinsko Beckert and Christopher S. Palenik; Microtrace, LLC

The use of nanotechnology and engineering of nanomaterials has grown exponentially in the last decade, and has found widespread application across a number of disciplines, including biology, medicine, electronics, energy, optics, and materials manufacturing, among others.  These nanoparticles and other subvisible particles are present in nearly all forms of existing trace evidence, yet currently the overwhelming majority of trace examinations focus exclusively upon larger particles.  In this era where highly engineered nanoscale materials are being introduced at increasing rates, it is inconceivable that such materials are not being regularly examined as forensic evidence.  Practical forensic research is currently being undertaken by the authors in order to systematically develop approaches for the isolation, analysis, and interpretation of particles on the nanoscale, effectively equating the sensitivity of trace evidence to that of DNA analysis.  While the smallest particles in this range may require higher resolution instrumentation, the majority of these particles can be characterized effectively by applying the suite of microanalytical methods present in most trace evidence laboratories today (stereomicroscopy, polarized light microscopy, and scanning electron microscopy).  Here we present the first part of our research: describing the relevance, classifications, and applications of nanoparticles, then following with information about how these particles can best be recognized and collected in a forensic science laboratory.


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