Preparation and Voltammetric Study of a Composite Titanium Phosphate/Nickel Hexacyanoferrate and Its Application in Dipyrone Determination

摘要

This paper describes the preparation, characterization and electroanalytical application of a composite consisting of titanium phosphate modified with nickel hexacyanoferrate. Titanium phosphate (TiPh) was formed from the reaction of titanium isopropoxide with H 3 PO 4 and deionized water. Next, the reaction of TiPh was performed with a metal ion (Ni +2 ) and potassium Hexacyanoferrate, designated as TiPhNIHCF. Spectroscopic techniques such as vibrational spectroscopy, X-ray diffraction (XRD), diffuse reflectance and cyclic voltammetry were used to characterize the TiPh and TiPhNiHCF. The graphite paste electrode containing TiPhNiHCF exhibited a redox couple with average potential (E q ’) of 0.61V vs Ag/AgCl (KNO 3 1.0 mol L -1 ; v = 20 mV s -1 ) attributed to redox process Fe II (CN) 6 /Fe III (CN) 6 . The redox couple presents a sensitive response for determining dipyrone. The system showed a detection limit of 3.75 x 10 -4 mol L -1 and standard deviation of 1.8 % for n = 3, with an amperometric sensitivity of 34.84 mA / mol L -1 . The modified electrode was electrochemically stable and showed good reproducibility.