Comparison of microsampling for PFAS blood analysis: Enabling cheap high-resolution biomonitoring

Environmental contaminant human biomonitoring is a powerful risk assessment tool. Recent developments in the biomonitoring of per- and polyfluoroalkyl substances (PFAS) have incorporated the use of microsampling technologies for sample collection. Microsampling enables the collection of individual high-resolution biomonitoring data and access for previously under-represented populations by postal applications. Despite these advancements, a fundamental evaluation of microsamplings suitability to at-home sampling, postage and storage at room temperature has not been undertaken. Therefore, a comparison of microsampling technologies viability for large biomonitoring initiatives was undertaken.

Dried blood spots (DBS) (Whatman 903), volumetric absorptive microsampling (VAMS) (Neoteryx Mitra), and capillary action DBS (Neoteryx hemaPEN) were compared for sample stability, reproducibility and susceptibility to contamination in the home sampling environment and postage. Sample stability was evaluated by monitoring the change in PFAS recovery at set timepoints from sample collection. After 35 days, the change in individual PFAS was greater than 10 % for five PFAS by the hemaPEN, four by DBS and zero by the Mitra. Reproducibility and contamination susceptibility were evaluated by participants (n = 20) collecting horse blood samples in their homes. Each participant collected a 'blank' and 'spiked' blood sample with each device (n = 120), sending them by post to the Australian Laboratory for Emerging Contaminants (ALEC) for extraction and analysis. No contamination of blank samples was observed, with the Mitra and hemaPEN respectively retaining 45 and 37 of the 49 PFAS within 70-130 % recovery and less than 20 % RSD at 5 ng/mL when sampled at home, whereas DBS only retained 16 PFAS.

This study demonstrates the viability of blood microsampling for PFAS within the home and the stability of these samples throughout postage at ambient temperatures. The home sampling environment did not contaminate any of the microsampling devices tested. However, VAMS samples were the most stable and robust under these conditions and are well suited to at-home sampling applications and larger PFAS biomonitoring initiatives.