Additive-manufactured sensors for biofuel analysis: copper determination in bioethanol using a 3D-printed carbon black/polylactic electrode.

We show that fused deposition modelling (FDM) 3D-printed electrodes can be used for quality control of fuel bioethanol. 3D-printing using carbon black/polylactic acid (CB-PLA) filaments resulted in conductive and biodegradable electrodes for biofuel analysis. As a proof-of-concept, copper determination in fuel bioethanol was performed, as such ions catalyse oxidation processes during storage and transport. Square-wave anodic-stripping voltammetry (SWASV) of copper was achieved after sample dilution in 0.1 mol L-1 HCl as supporting electrolyte (resulting in 30:70% v/v ethanol:water). The linear responses were in the range between 10 and 300 μg L-1 (R = 0.999), inter-day precision was lower than 8% (n = 10, for 20 μg L-1) and limits of detection (LOD) and quantification (LOQ) using 180 s as deposition time were 0.097 μg L-1 and 0.323 μg L-1, respectively. Recovery values between 95 and 103% for the analysis of bioethanol spiked with known amounts of copper were obtained. These results show great promise of the application of 3D-printed sensors for the quality control of biofuels. Graphical abstract.