Development of an Electroanalytical Method for the Simultaneous Determination of Trace Elements in Stingless Bee Honey Samples Using a Boron-Doped Diamond Electrode
摘要
Stingless bee honey is a food rich in minerals and other chemical compounds essential for nutritional purposes. However, if honey is contaminated with trace elements, its quality is compromised, making it unsafe for consumption. The electroanalytical method was optimized to determine simultaneously Cd2+, Cu2+, Pb2+, and Zn2+, using a boron-doped diamond electrode. Different electrolytes were tested: acetic acid-acetate buffer 0.1 mol L−1 (pH 3.6, 4.6, and 5.6), and Britton-Robinson buffer 0.1 mol L−1 (pH 2.0, 4.0, 5.0, 6.0, and 7.0). Acetate buffer (0.1 mol L−1, pH 5.6) was selected as the supporting electrolyte since the current signals for the four analytes were well-defined. Six electroanalytical parameters of square-wave anodic stripping voltammetry were studied using a full factorial design and a central composite design. The selected variables were: − 1.50 V, 240 s, 600 rpm, 20 mV, 30 Hz, and 85 mV for potential deposition, deposition time, stirring rate, step potential, frequency, and pulse amplitude, respectively. The limits of detection obtained for Cd2+, Cu2+, Pb2+, and Zn2+ were 2.25; 1.01; 3.41, and 3.32 μg L−1, respectively. The accuracy of the method was evaluated with a recovery test in different stingless bee honey samples fortified with the analytes, obtaining values ranging from 75.3–109.1%; 79.9–111.2%; 74.3–106.7%; and 73.6–106.7%, for Cu2+, Cd2+, Pb2+, and Zn2+, respectively. The electrochemical method performed well in simultaneously determining these analytes in the honey sample at low concentration levels.