Objective To establish a new inhibitory kinetic spectrophotometric method for the determination of trace Sb3+ in water sample. Methods A new inhibitory kinetic spectrophotometric method for the determination of trace Sb3+ was established based on the inhibitory effect of Sb3+ on the oxidation of thionine by H2O2 in a buffer solution of NH3-NH4Cl at pH=10.50. Results The linear range of this method was 0.004-0.40 ?g/ml, r=0.999 2,the limit of detection was 1.71?10-3 ?g/ml, and RSDs were 1.4%～ 2.1% , the recovery rates were 96.2% -101.9% . Conclusion This method is accurate, fast, simple and applicable to the determination of antimony content in environment water samples.

A glassy carbon electrode (GCE) modified with gold nanoparticles loading on the reduced graphene oxide (rGO)-multi-walled carbon nanotubes (MWCNTs) composite film was fabricated by a two-step procedure.Firstly, rGO-MWCNTs composite were prepared by in-situ chemical reduction method with hydrazine as a reducing agent.Then, AuNPs were deposited on the surface of rGO-MWCNTs using simple cyclic voltammetry.This modified electrode was characterized using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and electrochemical methods.Furthermore, the electrochemical behavior of bisphenol A (BPA) was also investigated using this modified electrode.The results showed that the modified electrode had high electrochemical activity for the oxidation of BPA.In 0.10 mol/L phosphate buffer solution (PBS, pH 7.0), the linear range for the determination of BPA with differential pulse voltammetry (DPV) was in the range of 5.0 × 10-9 -1.0 × 10-7 mol/L and 1.0 × 10-7-2.0 × 10-5 mol/L.The detection limit was 1.0 × 10-9 mol/L (S/N=3).The as-prepared modified electrode was successfully used to determine BPA in river water and the shopping receipt samples with recovery ranges of 97%-110% and 98%-104%, respectively.