Halide Ions sensing in water via silver nanoprism self-assembled chips

A silver nanoprism self-assembled monolayer was constructed, and as a novel nanosensing chip, it was applied for the determination of halide ions in water, including Cl–, Br– and I–. The sensing mechanism was based on different reaction rates in the shape-conversion processes of silver nanoprisms to nanodisks when they encountered halide ions with different concentrations. The extinction spectra of silver nanoprisms were in situ recorded in the sculpture processes. The shape conversion reaction rate, represented by the decreasing inplane dipole band intensity of silver nanoplates versus the reaction time (dI/dt), was calculated, displaying a Logistic relationship with the concentrations of halide ions. The lowest detection concentrations were 300, 3.0 and 3.0 M (equal to 10.63, 0.24 and 0.38 mg/L) for Cl–, Br– and I–, respectively. The interference experiments were carried out and the results showed that most anions involving F–, PO3– 4, HPO2– 4, H2PO– 4, SO2– 3, and SO2– 4 had no effect on the shape transformation of silver nanoprisms, except S2O2– 3 and S2– presenting minor effect when their concentrations were fifteen times of those of the analytes. This new nanosensing film has fast response to halide ions and the advantage of convenient transportation and storage, which is applicable to halide ions detections in water.