Plumeria rubra f. rubra: A Natural Chelating Ligand for Cu2+ ion

Abstract

 Numerous parts of natural plants, especially flowers, can be used as pH sensors. Anthocyanins, which are found in numerous plants and are pH-sensitive, can be employed to measure the amounts of acids and bases. Flowers from Plumeria rubra come in a range of vibrant colours. One of these, the pinkish-red Plumeria rubra f. rubra flower, has been studied for its capability of detecting Cu²⁺ ions and their complex coordination entities. It has been observed that the cupric ions in the methanolic extract of Plumeria rubra f. rubra petals create an observable, acute, and distinct wavelength shift in the UV-VIS spectrophotometer. The effects of several counterions, such as sulphate, chloride, nitrate, and acetate, are also studied using the same cupric ion under equivalent experimental conditions.  This observation suggests that Plumeria rubra f. rubra petals may contain compounds that can interact with cupric ions, potentially leading to the development of new analytical methods for detecting these compounds. Further research is needed to fully understand the mechanism behind this interaction and its potential applications.