Quercetin capped Au-Ag bimetallic nanoparticles for the detection of calcium dobesilate monohydrate in biological and environmental samples

Abstract

The study details the synthesis of quercetin-capped Au-Ag bimetallic nanoparticles (Qct-AuAg BMNps) in an aqueous environment. UV visible spectra showed absorbance peak of gold and bimetallic nanoparticles at 524 nm and 403 nm, respectively. The SEM analysis of Qct-AuAg BMNps showed an average particle size of 67.5 nm with good uniformity (PdI: 0.386). FTIR confirmed the presence of respective functional groups in Qct-AuAg BMNps. The Qct-AuAg BMNps were used as a colorimetric sensor for detecting calcium dobesilate monohydrate (CDM) in aqueous solutions, showing a linear spectrophotometric relationship with CDM concentration ranging from 0.000001 mM to 10 mM (R² = 0.9984). The detection and quantification limits were 1.66 × 10⁻⁶ and 2.71 × 10⁻⁵ mM, respectively. The binding constant (K_a) was 9.8 × 10⁴ M⁻¹, with a 1:1 stoichiometry confirmed by Job's plot. The Qct-AuAg BMNps were successfully used to detect CDM in tap water and serum samples. The synthesis process was optimized using Box Behnken Design, with the optimal conditions found at 50 °C, 2 mM quercetin, and a 5:1 silver-to-gold ratio. Therefore, the synthesized quercetin capped gold silver bimetallic nanoparticles were proved effective for the detection of CDM in liquid samples.