Voltammetric determination of 5-hydroxytryptamine based on the use of platinum nanoparticles coated with molecularly imprinted silica

The authors describe an electrochemical sensor for the determination of 5-hydroxytryptamine (5-HT; serotonin). It is based on the use of platinum nanoparticles (PtNPs) coated with molecularly imprinted silica (MIS). The MIS-coated PtNPs were prepared from 5-HT, PtNPs, phenyltrimethoxysilane and tetraethoxysilane that act as template, support, functional monomer and cross-linker, respectively. The MIS-coated PtNPs were characterized by Fourier transfer infrared spectroscopy and transmission electron microscopy. The MIS-coated PtNPs were drop-cast onto a glassy carbon electrode (GCE) to obtain an electrochemical sensor for 5-HT which exhibited fast response and high recognition ability for 5-HT. The imprinting factor of this electrode for 5-HT is 4.12, which is higher than that for its analogs. Under optimized conditions and at a typical working potential of 0.29 V (vs. Hg/Hg 2 Cl 2 ), the electrode has a linear response in the 0.05–80 μM 5-HT concentration range and a 0.02 μM detection limit. The electrode was successfully applied to the determination of 5-HT in human serum samples. Molecularly imprinted silica-coated platinum nanoparticles were prepared using surface imprinting technique. A glassy carbon electrode modified with the surface imprinted material exhibits fast response in detecting 5-hydroxytryptamine, a low detection limit, good selectivity, reproducibility and stability.