Serotonin sensor based on a glassy carbon electrode modified with multiwalled carbon nanotubes, chitosan and poly(p-aminobenzenesulfonate)

A glassy carbon electrode was modified with a nanocomposite prepared from poly(p-aminobenzene sulfonic acid), multi-walled carbon nanotubes and chitosan to obtain a differential pulse voltammetric sensor for serotonin that is remarkably stable and displays enhanced current response. Its peak current (at 0.38 V vs. Ag/AgCl) varied linearly with the concentration of serotonin in the 0.1–100 μM range, and the detection limit is 80 nM (at an S/N of 3). The sensor was successfully applied to the determination of serotonin in (spiked) human blood serum. An electrode modified with MWCNTs, chitosan and poly(p-aminobenzene sulfonate) gives significantly enhanced signals for serotonin and improves its oxidation peak current as shown in plot (d) due to improved direct electron transfer.