Abstract:

In hydrochloric acid solution with pH=4.1， Bi(Ⅲ) can react with alizarin red(AR) and cetyltrimethylammonium bromide(CTMAB) to form ternary ion-association complexe particles(the combination proportion was defined as n(Bi(Ⅲ))∶n(AR)∶n(CTMAB)=1∶3∶3). In this case, the resonance light scattering(RLS) intensities are enhanced greatly. The maximum RLS wavelength locates at 364 nm. The optimal conditions of the reaction, influence factors and the effect of coexisting substances were investigated. In addition, the reaction mechanism of the ternary ion-association complex was discussed. Under the optimal experimental conditions of 2.5 mL 1.0×10-4 mol/L alizarim red and 2.0 mL 1.0×10-4 mol/L CTMAB, the resonance scattering intensity(ΔI364 nm) was linearly related to the concentration of Bi(Ⅲ) in the range of 0～0.384 mg/L with a detection limit of 5.898×10-8 g/L. The method can be applied to the determination of Bi(Ⅲ) in water samples. The result was satisfactory and the recoveries were 99.5%～100.2% at the concentrations ranging from 0.552 to 0.831 μg/L, and the relative standard deviation was less than 2.7%. A sensitive, simple and new resonance light scattering method for determination of trace amount of Bi(Ⅲ) in environment was set up using the alizarin red as a spectrum probe.

Key words: Bismuth(Ⅲ), Alizarin red, CTMAB, Resonance light scattering