One-pot facile preparation of Ag nanoparticles for chloride ion sensing

A simple and facile method of Ag/dopamine modified poly(γ-glutamic acid) nanoparticles (Ag/γ-PGA-DA NPs) was conveniently achieved. By simply adding AgNO 3 to the aqueous solution of γ-PGA-DA copolymer, Ag + was adsorbed in the copolymer and spontaneously reduced to Ag NPs by the dopamine moieties of γ-PGA-DA, leading to the formation of Ag/γ-PGA-DA NPs. In the reaction process, γ-PGA-DA copolymer was used as stabilizer and reductant simultaneously, avoiding the use of extra toxic reducing reagents. The resultant Ag/γ-PGA-DA NPs were used to modify electrode through simple casting method and exhibited a good analytical performance for chloride ion. The Ag/γ-PGA-DA NPs modified electrode responded linearly to chloride ion in the concentration range of 1 × 10 −8 to 1 × 10 −3  mol L −1 . Compared to other published methods for chloride ion sensing, our prepared modified electrode had much wider detection range for chloride ion sensing.