Silver nanoparticles as colorimetric probe for selective determination of Hg²⁺ from milk samples with ultrasound‐assisted extraction protocol

The present investigation demonstrates a simple, sensitive and selective colorimetric probe for the detection of Hg 2+ in milk samples employing redox interaction of Hg 2+ ions with citrate‐stabilised silver nanoparticles, inducing colour change from yellow to colourless. Milk samples were pretreated by ultrasound assistance in acidic media. The detection limit (LOD) was 6.17 ppb using UV–Visible spectrophotometer with linear correlation ( R 2 = 0.9901) at 10–2000 ppb solution of Hg 2+ ions. Developed probe was highly selective to Hg 2+ over different interfering metal ions and can be effectively employed to identify Hg 2+ in milk samples.