Determination of iodide in urine based on chemiluminescence system of cerium (IV)–tween 40–iodide

In acidic medium, the oxidation reaction of cerium (IV) with iodide can produce strong chemiluminescence (CL) in the presence of surfactant tween 40 as an enhancer. On this basis, a flow injection method with CL detection was established for the determination of iodide. The method is simple, rapid and effective to determine iodide in the range of 8.0×10−8–5.0×10−5 mol/L with a determination limit of 5.0×10−8 mol/L. The relative standard deviation is 2.7% for the determination of 5.0×10−6 mol/L iodide (n=11). The method has been applied to determine the content of iodide in urine with satisfactory results. Furthermore, it is suggested that the light emission from cerium (IV)–tween 40 reaction is probably because of the formation of singlet oxygen 1O2⁎ and the emitter is excited oxygen molecular pairs O2(1Δg)O2(1∑g−).