The use of Clitoria ternatea as sustainable detection tool for Ni (II) and Cu (II) ions in simple paper-based analytical device

Abstract

Abstract Clitoria ternatea plants was growth widely in Indonesia. It was used as natural coloring in food or supplements. In this study, the C. ternatea flower was extracted using ethanol 70% and used for detection of metal ions (Ni, Cu) in aqueous medium. The ability of anthocyanins in C. ternatea extract to react with metal ions was studied using UV-Visible spectroscopy. It was found that the complex of metal ions with C. ternatea flower extract making the hypsocromic effect to the spectra of C. ternatea pure extract. Furthermore, simple paper based analytical device attached with C. ternatea extract was used as test spot to detect the metal ions. It reveals that the color of C. ternatea extract was changed and the calibration curve was obtained. The limit of detection (LOD) in the optimum pH for Ni (II) and Cu (II) was 8.89 ppm, and 4.49 ppm, respectively. Thus, this study showed that C. ternatea flower extract provides sustainable color detection for metal ions with economic and environmental benefits.