Analysis Methods for the Detection of Plastic Particles in Biological–Environmental Samples

The detection of microplastics (MPs) and nanoplastics (NPLs) in biological samples is critical for understanding their environmental distribution and investigating human exposure, bioaccumulation and their potential health effects. This review provides an overview of current approaches used to detect plastic particles in in vitro and in vivo studies, focusing on microscopic, spectroscopic, spectrometric, chromatographic and flow-cytometry-based methods. Microscopy techniques, including optical, confocal, fluorescence, scanning electron (SEM), transmission electron (TEM), cryogenic electron (cryo-EM), and atomic force microscopy (AFM), enable the visualization and characterization of MPs and NPLs. Spectroscopic approaches, such as Fourier transform infrared (FT-IR) and Raman spectroscopy, are widely employed for polymer identification through characteristic molecular fingerprints. Spectrometric techniques, including single-cell inductively coupled plasma mass spectrometry (scICP-MS) and single-cell inductively coupled plasma time-of-flight mass spectrometry (scICP-TOFMS), provide sensitive elemental analyses, while flow cytometry offers high-throughput particle detection. Chromatographic approaches, particularly double-shot gas chromatography–mass spectrometry (Py-GC/MS), enable sensitive and specific polymer characterizations. Recent technological advances, including automated and high-resolution analytical approaches, are also discussed together with practical considerations for selecting appropriate methods according to the sample type and analytical objective. Collectively, these methods contribute to the assessment of plastic particle occurrence, bioaccumulation, and biological effects, supporting future environmental monitoring, human biomonitoring and risk assessment.