Graphene detection in air: A proposal based on thermogravimetric behaviour

Abstract

Graphene's production and application are growing in accelerated speed. In this scenario, it is imperative to guarantee the healthy and safe conditions to producers and consumers along the graphene value chain. Due to the unique characteristics of graphene, its characterization in complexes matrices is still a challenging endeavour. In this work, we show an ongoing methodology that aims to assess the exposition to nanomaterials inside a graphene pilot plant by adapting the current particulate matter sampling methodologies. A systematic study was performed by preparing different graphene dispersions which were deposited on clean quartz filters and on filters exposed to an outdoor environment. Real samples, containing indoor airborne material were also analyzed. Thermogravimetric analysis was performed in all samples and revealed that the thermal decomposition of the deposited graphene was detectable and occurred around 635 °C. The presence of a thermal decomposition event within the typical temperature range of graphene was also detectable in the real indoor sample. These results pointed out that thermogravimetric analysis can be used to detect small amounts of graphene suspended in air, being the key factor graphene's high thermal stability being the key factor. The methodology provides a robust way to improve air quality surveillance and exposure evaluation.