Sensitive and robust colorimetric assay for the detection of Hg2+ at nanomolar level from real samples by TMPM functionalized Ag-Fe NCs and it's photocatalytic and antimicrobial activities.

• 3-(Trimethoxysilyl) propyl methacrylate stabilized Ag-Fe nanocomposite was synthesized by chemical reduction method. • The Ag-Fe nano composite-glycine conjugate was able to detect Hg2+ in aqueous sample. • Ag-Fe nanocomposite showed high selectivity and sensitivity towards the detection of Hg2+. • The limit of detection of Hg2+ by Ag-Fe nano composite was 1.84 nM. • The Ag-Fe nanocomposite exhibit excellent photocatalytic and antimicrobial activity. In this study, a selective and sensitive colorimetric probe for the detection of mercury at nanomolar level was reported and the effective detection by the probe was performed with environmental samples. The colorimetric sensing platform was prepared based on Ag-Fe bimetallic- 3-(Trimethoxysilyl) propyl methacrylate framework. The UV–vis spectroscopy, X-Ray diffraction, high resolution transmission electron microscope, energy dispersive X-ray spectroscopy (EDS), thermal gravimetric analyzer, zeta sizer and particle size analyzer were used for the characterization of Ag-Fe nanocomposite. The detection of mercury by Ag-Fe-glycine nanoconjugate was indicated by the colour change from yellowish brown to colourless. The environmental sample was collected from Noyyal river and the estimated amount by the probe was almost similar to the result of atomic absorption spectroscopy analysis. The detailed study on the effect of pH, temperature and saline concentration on the detection was performed. In addition, metal interference study was performed to understand the influence of other metal ions on detection and quantification of Hg²⁺ by Ag-Fe-glycine nanoconjugate and the study reveals the practical application of the prepared probe. The limit of detection of Hg²⁺ by Ag-Fe nanocomposite was determined to be 1.8 nM. The prepared probe is found to be an effective system to detect mercury at very low nanomolar level from aqueous samples. In addition, the nanocomposite exhibited multifunctional properties including efficient photocatalytic and antimicrobial applications, indicates its wide applications in various sectors. [ABSTRACT FROM AUTHOR]