Environmentally Friendly Paints Yield Significantly Different IR Spectra Over Time

Document Type

Conference Session

Publication Date

6-4-2025

Abstract

Forensic comparison of paint chips is an essential type of trace evidence analysis. Standard paint chip analysis for chemical composition is performed rapidly using Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FT-IR). This process allows an examiner to determine the chemical “fingerprint” of the paint and identify the major components used to manufacture the paint, including the binders. Paint chips can also be compared to one another based on these spectra. While this methodology is regularly applied by the forensic science community for standard paint coatings as well as degraded paint samples, the advent of environmentally friendly paints has the potential to pose a new challenge to examiner interpretation. These environmentally friendly paints are advertised as being able to absorb volatile organic compounds from the air in the room in which they are painted. If these volatile organic compounds are being absorbed, this could potentially impact the infrared spectra produced in the analysis. This study examined two brands of these paints: SuperPaint® Interior Acrylic with Air Purifying Technology, by Sherwin Williams®, which claims it “helps reduce volatile organic compounds (VOCs) from potential sources like carpet, cabinets, and fabrics” and four different paint types by ECOS Paint®, which claims their paints include “a molecular sieve which is designed to both stop harmful volatile organic compounds from being released into the air and to trap them as they float though a room”. These paints were chosen due to their statement of absorbing and trapping volatile organic compounds. If these paints are absorbing volatile organic compounds, the expectation is that we would observe changes to the infrared spectra produced over time. Each paint was applied in two coats onto wooden craft sticks generating five replicate sticks. ATR-FT-IR spectroscopy was performed on all sticks in replicate starting at week zero to produce an initial spectrum, through 69 weeks. Spectra were normalized and eight spectral peaks were chosen to obtain absorbances. Absorbances analyzed with a single-factor ANOVA showed there was a significant difference in peak intensities over time (p < 0.05). Additionally, plotting peak intensities over time shows that these changes are not predictable depending on the brand of paint. These findings demonstrate the importance of being aware of societal changes impacting paint formulations. Environmentally friendly paints, such as these, have been increasing in the marketplace and forensic chemists need to be aware of how they can impact their analysis.

Host

Florida International University (FIU) - Global Forensic and Justice Center

Conference/Symposium

Global Forensic Science Symposium (GFSS)

City/State

Miami, FL

Department

College of Arts and Sciences

Comments

Co-authors: Emily Pintilie, BS*; Hailee Leach, BS*; Alanna Lecher, PhD; Lynn University, USA

*Presenting authors

Theme: “Collaboration in Forensic Science.”

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Emily Pintilie '24 is a biological science master's student, and Hailee Leach '25 is a biology student with a concentration in forensic science.

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