Inhibition kinetic determination of trace amount of iodide by the spectrophotometric method with rhodamine B.

Trace iodide was determined by inhibition kinetic method, which based on its inhibition effects on the reaction between rhodamine B (RhB) and KBrO(3) in H(2)SO(4) medium in 45+/-0.5 degrees C for 15 min. The signal difference (DeltaA, DeltaF) between inhibited reaction and non-inhibited reaction is linear with the concentration of iodide. The linear range were 2.0-6.0 and 1.0-6.0 ng mL(-1) and the detection limit were 0.06 and 0.07 ng mL(-1), respectively. The method has been applied satisfactorily to the determination of iodide in kelp.