Selective and sensitive sensing of copper(II) by natural compound C-21 steroid caudatin

Abstract

Selective and sensitive sensing of varied analytes is playing important role in assessing the concentration of different pollutants in aquatic system. In view of this, in the presented study a biocompatible C-21 steroid caudatin (1) has been isolated from C. otophyllum, characterized using multinuclear NMR spectroscopy and mass spectrometry. The obtained natural product had been used as photoluminescent sensor for selective and sensitive detection of cupric cation with limit of detection of 1.93 ppm and KSV value of 3.45 × 103 M−1. Also, interference experiments revealed that 1 can selectively detect Cu2+ ion in presence of other metal cations. Further, theoretical calculations have been done to assess the reason for selectivity of this steroid against the copper cation. The integrated experimental and theoretical studies reveals that the plausible reason for the selectively and sensitivity of caudatin to detect Cu2+ was accredited to the better interaction between Cu2+ and caudatin as well as competitive absorption light due to UV–Vis spectral overlap operates between Cu2+ and caudatin that are collectively responsible for the quenching in emission of caudatin.