Silver nanoparticles doped three-dimensional hydrogel for electrochemical simultaneous sensing of heavy metal ions

• The conductive silver nanoparticles decorated hydrogel was synthesized by a mild one-pot polymerization method. • The hydrogel has the advantages of large surface area, high conductivity, excellent swelling ability and good adsorption capacity. • The prepared hydrogel sensor has excellent selectivity, wide linear range and good long-time stability for simultaneous detection of four heavy metal ions. • The prepared sensor is applicable to detect Cu 2+ in real river samples. Heavy metal ions have significant risks to both environment and human health, and their detrimental effects are irreversible. Therefore, a sensor capable of simultaneous detecting heavy metal ions with high accuracy presents a significant challenge. In this work, a conductive hydrogel was synthesized using 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), methacrylamide (MAM), and hydroxyethyl methacrylate (HEMA) as monomers, N, N’-methylenebis(acrylamide) as the crosslinker, through physically doping with silver nanoparticles. The prepared hydrogel has the characteristics of good conductivity, excellent swelling ability and high adsorption capacity for enrichment of heavy metal ions (HIMs). The three-dimensional network hydrogel was directly used for simultaneous detection of HIMs in multiplex system, with superior separation ability, good linear ranges, excellent reproducibility and good long-time stability. Additionally, this sensor can accurately detect Cu 2+ in river sample, demonstrating high precision and applicability. The fabrication of the hydrogel electrochemical sensor is simple and mild, allowing for the electrochemical capture of various HIMs and holds practical application prospect.