Sudan Blue II Dye loaded modified MCM-48: Colorimetric, Paper Strip, and Fluorescent Sensor for Cu 2+ ion

Abstract

Abstract In this work, Sudan Blue II dye is successfully grafted on the walls of chloro-functionalised MCM-48. The synthesized probe selectively detect Cu2+ ion by fluorescence spectroscopy. The probe designated as SB@modMCM-48 was characterized by various spectroscopic methods including FT-IR, SEM, EDX and N2 adsorption-desorption isotherm, etc. The fluorescent intensity of the probe is quenched by 14 times in presence of Cu2+ ion. The fluorescent detection is reversible, selective with low detection limits. The LOD and Ka (association constant) was calculated to be 1.45 × 10− 10 M and 5.38 × 107 M− 1 respectively with a linear range of detection. The addition of Cu2+ ion to the probe solution also imparted a visual color change. Paper strip sensor was also developed for naked eye detection of Cu2+. The low LOD limits, binding stoichiometric constant, etc. point towards high affinity of Cu2+ towards the nanosensor. Interestingly, the Cu2+:sensor complex selectively sense amino acid cysteine in its aqueous solution, with a limit of detection of 10.46 × 10− 8 M.