Determination of trace arsenic(iii) by kinetic spectrophotometry

In acetic acid medium,trace As(Ⅲ) can sensitively actyivate the indicating oxidative discoloration of indigo carmine la with KIO_4.The optimum condition and kinetic parameters are investigated and evaluated,a new method for determination of trace As(Ⅲ) is proposed.The detection limit is 1.82×10~(-6) g/L and the linear range is 0.0-40 μg/mL As(Ⅲ).It has been applied to the determination of trace As(Ⅲ) in environmental waters with satisfactory results.