2.5. Sample preparation
The juices samples, which included orange juice, vegetable juice, tea and honey, were purchased from a local supermarket. The juices were filtered using Whatman No. 1 filter paper. One milliliter of each solution was transferred to a volumetric flask and diluted to 10 mL with supporting electrolyte before analysis via the electrochemical procedure. The sample solutions obtained had concentrations within the range of the calibration graph. ICP–OES assays [32] were employed for purposes of comparison.