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 Hg²⁺ in milk samples employing redox interaction of Hg²⁺ 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 (R² = 0.9901) at 10–2000 ppb solution of Hg²⁺ ions. Developed probe was highly selective to Hg²⁺ over different interfering metal ions and can be effectively employed to identify Hg²⁺ in milk samples.