Development of nickel oxide electrode for application in dopamine detection

Abstract

This research studied the synthesis of nickel oxide as a catalyst for dopamine detection to modified working electrode by electrochemical with cyclic voltammetry. In the system, the potentiostat connect electrode with silver/silver chloride reference electrode and platinum counter electrode. In this study, the synthesis of nickel oxide by precipitation method was compared between using sodium hydroxide (NaOH) and urea (CH4N2O) as a precipitating agent and with/without surfactant adding. It was found that nickel oxide from both precipitating agents showed an improvement of the current response when compared with unmodified nickel oxide electrode. The study of nickel oxide loading on the electrode showed the highest current response at 0.078 mg of nickel oxide loading. The modification of nickel oxide by addition of surfactant and hydrothermal treatment that found the highest current response obtain from nickel oxide modified electrode that synthesized from precipitation with urea by addition of mixed surfactant of butanediyl-1, 4-bis(dimethyldodecylammonium bromide)(C12-C4-C12,2Br-) 0.04 mM and Sodium dodecyl sulphate(SDS) 8.2 mM and hydrothermal at 120 ºC. Determination of dopamine by oxidation of dopamine was improved electrochemical response by nickel oxide modified electrode at 0.3 V of apply voltage. The detection of dopamine was operated in 10 mM phosphate buffer solution, pH 7.0 show two linear range that are 3.125 – 100 and 100 – 500 µM with sensitivity 0.0498 and 0.01 µA/µM, respectively. The limit of detection was 1.75 µM.