Nanosized iron telluride for simultaneous nanomolar voltammetric determination of dopamine, uric acid, guanine and adenine

Nanocrystalline iron telluride (FeTe2) compound was synthesized chemically at room temperature via reduction of a homogeneous solution of tartrate complexes of Fe3+ and Te4+ with sodium borohydride. XRD, FESEM, and TEM studies were carried out for the structural characterization of the as prepared metal chalcogenide material. The XRD study revealed the successful formation of the orthorhombic phase of FeTe2 nanoparticles (nps) with a diameter of 20 nm. Electrochemical studies were carried out by employing cyclic voltammetry (CV) and differential pulse voltammetry (DPV) techniques. The cyclic voltammetry response confirmed the efficiency of the prepared FeTe2 modified graphite paste electrode (FeTe2/GP) towards the electrocatalytic oxidation of dopamine (DA), uric acid (UA), guanine (GU) and adenine (AD) in comparison with the graphite paste (bare GP) electrode. DPV results depicted the appearance of four well defined distinct oxidation peaks correspond to DA, UA, GU and AD with the peak potential separation of 146 mV (DA-UA), 413 mV (UA-GU) and 343 mV (GU-AD) when the FeTe2/GP electrode was dipped into the ternary biomolecule solution in the presence of phosphate buffer at pH = 6. This enables the simultaneous detection of all four analytes. Under the optimized experimental conditions, FeTe2/GP exhibited a wider linear range of 5-120 mu M, 3-120 mu M, 1-160 mu M and 3-100 mu M for DA, UA, GU and AD with the detection limit (S/N = 3) of 28 nM, 42 nM, 34 nM and 26 nM, respectively. Moreover, the as prepared sensor was successfully used for the analysis of spiked biological and pharmaceutical samples.