Abstract
Nanoplastics are persistent pollutants that may act as vectors of various inorganic and organic pollutants. Due to their small size and complex nature, their identification in environmental samples is still extremely difficult. The goal of this work is to investigate the ability of an electrolyte-gated carbon nanotube field-effect transistor (EG-CNTFET) based sensor to detect polystyrene nanoplastics (PS NPs) in a more realistic scenario in the presence of a typical environmental pollutant such as mercury. To do so, PS NPs/Hg2+ complexes are formed through the sorption of mercury ions (Hg2⁺ on the surface of carboxylated PS NPs, and the formation of Hg-O bonds, with a sorption efficiency of up to 7.9% w wNP−1. The EG-CNTFET sensor effectively detects these complexes in water, with an increase in normalized current of up to 27.4% (±12.7) after 5 min of measurement and stable values reached after 25 min. As proved, the reached values do not differ significantly from the pure PS NPs samples (29.7% (±6.9)). Therefore, this study demonstrates that the sensitivity of the developed EG-CNTFET is not affected by the NP surface modifications induced by Hg2⁺ binding, opening the possibility for its use for the real-time identification of NPs in complex environmental samples.