Infrared photothermal heterodyne imaging (IR-PHI) is an established all-optical, table-top approach for conducting super-resolution mid-infrared microscopy and spectroscopy on submicrometer-sized particles. The instrument’s capabilities are highlighted by its ability to operate in spectroscopically-crowded environments. This includes specimens obtained from environmental matrices where particulates with different morphologies, chemical compositions, and abundances exist. Here, proof-of-concept IR-PHI measurements have been conducted on anthropogenic micro- and nanoplastics (MNPs) derived from the breakdown of consumer products. In particular, IR-PHI is used to characterize MNPs extracted from steeped plastic teabags and floor dust from a household vacuum. IR-PHI results reveal the presence of complex MNP structures made of polyamide fibers and acrylonitrile butadiene styrene MNPs.
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