Zeolitic imidazolate frameworks and cobalt-tannic acid nanocomposite modified carbon paste electrode for simultaneous determination of dopamine, uric acid, acetaminophen and tryptophan: Investigation of kinetic parameters of surface electrode and its analytical performance

Abstract

In this study, we have created a particularly selective electrochemical sensor cobalt-tannic acid nanocomposite (ZIF-8@Co-TA) and a familiar metal organic framework (ZIF-8), which was then used to simultaneously determine acetaminophen (AC), dopamine (DA), tryptophan (Trp), and uric acid (UA) with wide linear ranges and low detection limits (LOD). In addition, we have applied chronoamperometry, differential pulse voltammetry (DPV), electrochemical impedance spectroscopy, and cyclic voltammetry so that the electrochemical features of the fabricated electrode could be assessed. The eminent catalytic activity and high-level conductivity of ZIF-8@Co-TA has led to perfectly separated peaks, and to improved peak currents of DA, UA, AC, and Trp. According to the results, the ΔEp of 130, 120, 310 mV vs. SCE were reported as the level of separation of anodic peak potentials for DA-UA, UA-AC, and AC-Trp, respectively. With LOD of 3.4, 1.2, 5.1 and 6.7 nM, the maximum currents linearly depended on DA, UA, AC and Trp concentrations in the ranges of 0.02–0.44 μM (Sbk/m = 3). Good repeatability and stability were observed after determining DA, UA, AC, and Trp, which was carried out through successfully challenging the chemically modified electrode with some interfering compounds and evaluating it in real samples. Therefore, it seems that fabricated sensor can be properly exploited for clinical experiments and pharmaceutical applications.