Selective determination of homocysteine at physiological pH using nanostructured film of aminothiadiazole modified electrode

We report the selective determination of homocysteine (HCY) in the presence of one of the very important interferents, ascorbic acid (AA) using electropolymerized film of 2-amino-1,3,4-thiadiazole (ATD) modified glassy carbon electrode (GCE) at physiological pH for the first time. An atomic force microscopic image showed that the electropolymerized film of ATD (p-ATD) formed a spherical like structure with a thickness of 25 nm. This nanostructured film oxidized HCY at 0.55 V while bare GCE failed to oxidize it at physiological pH. Further, p-ATD modified electrode successfully separated the voltammetric signals of AA and HCY with a peak separation of 490 mV. The amperometric current was increased linearly from 100 to 1400 nM HCY and achieved the detection limit of 51 pM (S/N= 3). The present modified electrode showed better recoveries for spiked HCY in human blood serum samples. (C) 2010 Elsevier B.V. All rights reserved