Fourier-transform infrared (FTIR) spectroscopy, especially in its micro-FTIR (μ-FTIR) variant, is the most widely used method for identifying and quantifying micro- and nanoplastics in environmental samples.

FTIR spectroscopy identifies plastics by measuring their unique infrared absorption spectra, allowing precise polymer characterization even in mixed or complex matrices. Recent innovations integrate μ-FTIR with AI-powered image processing, enabling semi-automated particle recognition across different filter membranes without manual pre-sorting. This advancement significantly expedites analysis while maintaining accuracy, addressing the challenge of detecting particles down to the nanoscale amidst biological or mineral debris.