ELECTROCHEMICAL INVESTIGATION OF DA AND UA ON CARBOXYLATED GRAPHENE OXIDE/LANTHANUM ELECTRODES WITH SUNDRY CONTENT OF CTAB

Glassy carbon electrodes (GCE) were modified by carboxylated graphene oxide/lanthanum with various concentrations of hexadecyl trimethyl ammonium bromide (CTAB), and the treated electrodes, called CTAB/GO-COOLa/GCE, were prepared for the detection of uric acid (UA) and dopamine (DA) by using the differential pulse voltammetry (DPV) and the cyclic voltammetry (CV). The results show that the modified electrode’s electrocatalytic activity could be affected by several factors in the examination, they are the pH value of the system, the main content of CTAB, various concentrations and rates of scan. With a combination of carboxylated graphene oxide/lanthanum and CTAB, the resulted CTAB/GO-COOLa/GCE sensors showed preeminent selectivity and obvious catalytic property toward the electro-oxidation of UA and DA. In optimized conditions, the response of the CTAB/GO-COOLa/GCE electrode for DA was linear in the region of 0.03–500.0 μ M with detection limits of 0.036 μ M (S/N = 3 ) . Two linear response ranges for the determination UA were obtained from ranges of 1 to 200 μ M and 200 to 1300 μ M with a detection limit of 0.42 μ M (S/N = 3 ) . Moreover, the refined electrode was used in the inspection of DA and UA in real samples of serum and urine successfully, displaying its potential application of real samples involved in electroanalysis.