posted on 2020-03-11, 19:13authored byAna C. Marques, Ana R. Cardoso, Rodrigo Martins, M. Goreti F. Sales, Elvira Fortunato
Expanding
the single molecule detection, enabled by laser-induced
graphene (LIG) technology, for portable and on-site analysis, a dual
molecule system with a two-working-electrode architecture was developed
for ascorbic acid (AA) and amoxicillin (AMOX) detection, which are
currently used in aquaculture and persist as water contaminants. The
biorecognition element of each target compound was a suitable molecularly
imprinted polymer (MIP). The AMOX MIP was developed herein for the
first time and assembled by electropolymerization of eriochrome black
T (EBT). It showed a wide linear response from 50 nM to 100 μM,
with a sensitivity of −13.32 μA/decade. Calibration curves
revealed good squared correlation coefficients (R2 > 0.99) with a limit of detection (LOD) of 11.98
nM.
AA MIP was assembled according to a previous work reported in the
literature, displaying a linear response from 1.5 to 4 mM and a sensitivity
of 1.356 μA/decade. The developed dual-LIG device was further
tested in real samples and successfully applied to the analysis of
binary mixtures prepared in environmental water samples from a well.
Overall, the proposed device allows in situ analysis
of two different molecules and holds an exceptionally low-cost design
when compared to competing architectures in the literature, and the
fabrication method here employed offers the possibility of easily
adjusting the desired architecture on demand.