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Physical and Chemical Trace Evidence from 3D-Printed Firearms, and Use of a Quadcopter for Targeted Sampling of Gaseous Mercury in the Atmosphere

NCJ Number
310334
Date Published
March 2025
Length
24 pages
Annotation

This dissertation addresses the forensic analysis challenges presented by 3D-printed polymer firearms, describing the research methodology and outcomes that can give forensic practitioners the ability to identify and source unknown polymer evidence using chemometric analysis including principal component analysis.

Abstract

This paper presents the research methodology and findings from a project that used several novel analytical methods to analyze trace chemical evidence from 3D-printed firearms. Methods used include direct analysis in real time-mass spectrometry (DART-MS) as well as targeted aerial sampling for quantitation of gaseous mercury. The mercury project relied on a quadcopter unmanned aerial vehicle (UAV) along with gold-coated quartz sorbent tubes that targeted and captured the gaseous mercury, which was then quantified in both the laboratory and in the field, using cold vapor atomic fluorescence spectrometry (CVAFS). The paper describes the methodology used next for outcome verification. The method was applied near coal-fired power plants, a petroleum refinery, and a municipal landfill. The dissertation discusses the project’s implementation and results; it also discusses implications for forensic analysts, noting that the method was useful to probe mercury concentrations aloft, and to quantify emissions from potential point-sources in the field through the use of an inexpensive quadcopter UAV and sampling setup.

Date Published: March 1, 2025