Palladium nanospheres embedded Polythiophene nanocomposite modified electrochemical sensor: A highly sensitive voltammetric detection of L-Tryptophan in sunflower seeds oil

This present work elucidates the direct electrochemical detection of L-tryptophan (L-Try) using palladium (Pd) nanosphere embedded polythiophene (PT) nanocomposite created by electrostatic interaction as determined by the protonated structure of PT-Pd in conjugation with a weak Vander Waals force. Amphipathic amino acids like tryptophan are well known for their complex chemical properties and side chain dipole functionalization. The enhanced conductivity of the modified PT-Pd glassy carbon electrode (GCE) is a result of the effective interaction between the sulfur groups of PT and the free α-amine and α-carboxylic acid groups of L-Try. Furthermore, depending on the surface charge of the prepared Pd nanospheres, the aromatic structure and indole ring of a planar L-Try can interacts with them easily. The L-Try's peak current increases linearly across a concentration range of 100 nM to 1 mM. The sensitivity with good linearity in a broad linear range 0.157 µA M -1 cm -2 , with significant limit of detection which is calculated as 1.46 nM. The PT-Pd modified GCE was shown to have excellent electro-catalytic activity and this newly developed sensor shown satisfactory results against L-Try concentration in real samples, such as sunflower seeds oil.