Sensors for 5-hydroxytryptamine and 5-hydroxyindole acetic acid based on nanomaterial modified electrodes

Simultaneous voltammetric determination of serotonin and 5-hydroxyindole acetic acid has been described at single walled carbon nanotube modified glassy carbon electrode and gold nanoparticles modified indium tin oxide electrode. The method described is fast, simple, accurate with detection limits as low as 32 nM for 5-hydroxytryptamine (5-HT) at single-walled carbon nanotube modified glassy carbon electrode and 27 nM for 5-hydroxyindole acetic acid (5-HIAA) at gold nanoparticles modified indium tin oxide electrode. Linear variation of peak current with change in concentration was observed in the concentration range 0.1–100 μM for 5-HT and 5-HIAA. Application of the method for non-invasive determination of the compounds in urine samples has also been described. The inter- and intra-day stability of the electrodes were also determined and electrodes were found to be sufficiently stable for 1 week.