Identification of micro-/nanoplastics in human placental blood using comprehensive multidimensional pyrolysis - gas chromatography x ion mobility mass spectrometry

Micro-/nanoplastics (MNPs) are ubiquitous environmental contaminants and there has been a growing concern about their potential adverse effects on human health. The present study reports on the development of a novel pyrolysis-gas chromatography x ion mobility mass spectrometry method to identify MNPs in placental blood, while reducing false positive detections from matrix interferences.

Base digestion and filtration yielded acceptable recoveries: 90 ± 11 % for polystyrene (PS), 93 ± 16 % for polyethylene (PE), and 53 ± 18 % for polypropylene (PP). Limit of Detections (LODs) ranged from 0.15 to 0.60 μg/mL, depending on the polymer. Placental blood samples were collected from 46 donors and analyzed in triplicate, resulting in measurements for 138 samples. Forty-three samples contained at least one polymer type above the limit of detection, and 10 samples contained at least one polymer type above the limit of quantification. Total plastic concentration in samples with detectable levels (>LOD) of MNPs averaged 0.9 μg/mL and ranged between 0.2 and 3.6 μg/mL. Orthogonal separation by ion mobility revealed that 10/22 PE detections were false positives.

This study is the first to integrate ion mobility separation to differentiate between genuine and false detection of PE in human blood. Without the aid of ion mobility separation, the concentration of PE in individual samples was overestimated by up to 233 % of the mean MNP concentration, underlining the importance of multidimensional separation for individual exposure analysis.