Assessing the Efficacy of Pyrolysis–Gas Chromatography–Mass Spectrometry for Nanoplastic and Microplastic Analysis in Human Blood

Humans are constantly exposed to micro- and nanosized
plastics
(MNPs); however, there is still limited understanding of their fate
within the body, partially due to limitations with current analytical
techniques. The current study assessed the appropriateness of pyrolysis–gas
chromatography–mass spectrometry (Py-GC-MS) analysis for the
quantification of a range of polymers in human blood. An extraction
protocol that reduced matrix interferences (false positives) of polyethylene
(PE) and polyvinyl chloride (PVC) was developed and validated. Extraction
recoveries ranged 7–109%, although surface-modified polystyrene
(carboxylated) increased nanoparticle recoveries from 17 to 52%. Realistic
detection limits were calculated for each polymer, accounting for
matrix suppression and extraction recovery. These were up to 20 times
higher than nominal detection limits calculated with Milli-Q water.
Finally, the method was tested with a pilot study of the Australian
population. PE interferences were reduced but still present, and no
other polymers were above detection limits. It was concluded that
Py-GC-MS is currently not a suitable analysis method for PE and PVC
in biological matrices due to the presence of interferences and nonspecific
pyrolysis products. Furthermore, while it is plausible to detect some
polymers in blood, the estimated exposure concentrations needed are
approaching the detection limits of the technique.