A novel amperometric biosensor for the determination of Al(III) based on the inhibition
of the enzyme superoxide dismutase has been developed. The oxidation signal of epinephrine
substrate was affected by the presence of Al(III) ions leading to a decrease in its amperometric current.
The immobilization of the enzyme was performed with glutaraldehyde on screen-printed carbon
electrodes modifiedwith tetrathiofulvalene (TTF) and different types ofnanoparticles. Nanoparticles
of gold, platinum, rhodium and palladium were deposited on screen printed carbon electrodes
by means of two electrochemical procedures. Nanoparticles were characterized trough scanning
electronic microscopy, X-rays fluorescence, and atomic force microscopy. Palladium nanoparticles
showed lower atomic force microscopy parameters and higher slope of aluminum calibration curves
and were selected to perform sensor validation. The developed biosensor has a detection limit of
2.0 0.2 Mfor Al(III), with a reproducibility of 7.9% (n = 5). Recovery of standard reference material
spiked to buffer solution was 103.8% with a relative standard deviation of 4.8% (n = 5). Recovery of
tap water spiked with the standard reference material was 100.5 with a relative standard deviation of
3.4% (n = 3). The study of interfering ions has also been carried out.
