Simultaneous Determination of Thiocyanate and Oxalate in Urine using a Carbon Ionic Liquid Electrode Modified with TiO2-Fe Nanoparticles

A carbon ionic liquid electrode (CILE) modified with TiO2-Fe nanoparticles was constructed by incorporating TiO2-Fe nanoparticles into the paste matrix. Under the optimized experimental conditions, using differential pulse voltammetry (DPV), the oxidation of thiocyanate and oxalate were occurred at potentials of 0.740 V and 1.010 V, respectively, at the surface of the modified electrode. Observing a high peak current along with a suitable peak separation allowed introducing the first voltammetric sensor for simultaneous determination of these anions with high sensitivity without mutual interference. A wide linear range of 1.0 x 10(-5)-1.8 x 10(-3) M for thiocyanate with a detection limit of 6.4 X 10(-6 )M and a wide linear range of 5.0 x 10(-5)-3.0 x 10(-3) M for oxalate with a detection limit of 2.3 x 10(-5) M were obtained. The modified CILE showed good reproducibility, repeatability and storage stability as well as good selectivity. The proposed sensor was successfully applied for analysis of thiocyanate and oxalate in urine samples.