Electrochemical Determination of Uric Acid in Urine by Using Zeolite Imidazolate Framework-11 Modified Electrode
Tran Si Thanh, Phan Tu Qui, Nguyen Thi Thanh Tu, Trần Thanh Tâm Toàn, Tran Thi Bich Hoa, Le Van Thanh Sơn, Do Mai Nguyen, Trần Ngọc Tuyền, Đinh Quang Khiếu
Abstract
In the present article, the synthesis of zeolite imidazole framework-11 (ZIF-11) by ultrasonic-assisted hydrothermal process and its application as an electrode modifier for electrochemical determination of uric acid in urine are demonstrated. The obtained materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption isotherms. It was found that the ZIF-11 with rhombic dodecahedron topology and high surface area (1066 m2.g-1) was synthesized in a certain temperature and found in around 25–40°C, and other crystalline phases of zinc benzimidazolate deferring from ZIF-11 phase were found in less 25°C or higher than 40°C. The ZIF-11 is stable in the pH range 6-10. The modification of glassy carbon electrode was performed with ZIF-67 using the drop-casting procedure. The present ZIF-11 modified electrode was employed to study the electrochemical behavior of uric acid (UA). UA oxidation is catalyzed by this electrode in aqueous buffer solution (pH 7) with a decrease of 70 mV in overpotential compared to glassy carbon electrode. With the differential pulse–anodic stripping voltammetry (DP-ASV) method, the oxidation current of UA versus its concentration shows good linearity in the range 20–540μM ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi>R</a:mi> <a:mo>=</a:mo> <a:mn>0.998</a:mn> </a:math> ) with a detection limit of 0.48 μM ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>S</c:mi> <c:mo>/</c:mo> <c:mi>N</c:mi> <c:mo>=</c:mo> <c:mn>3</c:mn> </c:math> ). The obtained ZIF-11 modified electrode was applied in the detection of UA content in urine samples, and satisfied results were obtained.