Abstract

This study substantially synthesized the beta-type MnO2 nano-flowers assembled by the hierarchical nano-sheets using a simplified hydro-thermal procedure. According to the FESEM images, MnO2 nano-flower exhibited diameter of similar to 800 nm and fabricated with a lot of irregular sheets as a petal-like structure with thickness of several nano-meters. Therefore, the study focused on the construction of an electro-chemical sensor to simul-taneously determine theobromine (ThB), theophylline (ThP), as well as caffeine (CaF) on the basis of the beta-type hierarchical structure of the MnO2 nano-flowers (beta H-MnO2-NF) modified electrode (beta H-MnO2-NF/GCE). Analysis showed an acceptable linear association between the oxidation peak current and ThB, ThP and CaF concentration within the ranges between 0.01 and 320.0 uM with a limit of detection (LOD) equal to 8.7, 5.9, and 10.1 nM (S/N = 3), respectively. Additionally, this study intended to investigate ThB, Thp and CaF bio-availability in the five commercially available brands of the chocolate products and drug.