Non-enzymatic sensing of hydrogen peroxide using a glassy carbon electrode modified with a composite consisting of chitosanaEuroencapsulated graphite and platinum nanoparticles

We report on a non-enzymatic hydrogen peroxide (H2O2) sensor which makes use of a nanocomposite consisting of platinum nanoparticles (PtNPs) and chitosan-encapsulated graphite (graphite-CS). The composite was prepared by sonication of pristine graphite in chitosan (CS) in 5 % acetic acid. The PtNP decorated graphite-CS (graphite-CS/PtNPs) composite was prepared by electrodeposition of PtNPs on the graphite-CS modified glassy carbon electrode. The graphite-CS/PtNP composite was characterized by scanning electron microscopy, elemental analysis and FTIR spectroscopy. The modified electrode displays an enhanced reduction peak current for H2O2 when compared with electrodes modified with graphite/PtNPs and PtNPs. The modified electrode exhibits excellent electrocatalytic activity towards the reduction of H2O2, and the amperometric response is linear over the concentration range from 0.25 to 2890 mu M. The sensitivity and the detection limit are 0.465 mu Aai...mu MaEuro3/4(1) ai... cmaEuro3/4(2) and 66 nM, respectively. The sensor shows fast response (3 s) in detecting H2O2. It is also highly selective in the presence of potentially interfering compounds, and may therefore be used as a feasible platform for sensing H2O2 in real samples.