Electrochemical Determination of Rosmarinic Acid in Edible Flowers Using Ionic Liquid Modified Electrode

The current research focused on developing a nanocomposite of ionic liquid/CNTs paste electrode (IL/CNTs-PE) for use as a precise and sensitive electrochemical sensor to quantify rosmarinic acid (RA) as phenolic acid in a prepared sample of Lavandula angustifolia. Structural analyses using XRD and SEM revealed that IL was successfully incorporated on the surface of CNTs in the IL/CNTs composite. Electrochemical studies with CV and DPV demonstrated that combining ILs and carbon CNTs improves the electrocatalytic activity, selectivity, and sensitivity of IL/CNTs-PE to determine RA. The results showed a stable linear range of 0 to 680 μM and a sensitivity of 0.0951 μA/μM were achieved, with detection limits as low as 15 nM. The results of determining RA in prepared real samples from Lavandula angustifolia showed low RSD values (4.33 to 5.14%) and high recovery values (98.75 to 99.50%), indicating that the IL/CNTs-PE results were accurate and valid for determining RA level in a prepared sample from an extracted liquid of flowers.