Determination of trace mercury by solid substrate-room temperature phosphorimetry based on catalytic effect of Hg(2+) on formation of the ion association complex [Fe(bipy)(3)](2+)[(FinBr(4))(2)](2-).

A new solid substrate-room temperature phosphorimetry method for the determination of trace mercury has been established. It bases on the fact that in acetic acid medium, Hg(2+) ion can catalyze the substitute reaction of CN(-) ligand in [Fe(CN)(6)](4-) by 2,2'-bipyridyl (bipy), and the resultant [Fe(bipy)(3)](2+) cation can react with FinBr(4)(-) anion of tetrabromofluorescein (HFinBr(4)) to form ion association complex [Fe(bipy)(3)](2+)[(FinBr(4))(2)](2-) which can emit phosphorescent signal on filter paper substrate. Under the optimum condition, the linear dynamic range of this method is 1.6-16fg per spot with a detection limit (LD) of 0.18fg per spot (0.4mul sample solution per spot), and the regression equation of working curve is DeltaI(p)=1.058+7.671 C(Hg(2+)) (fg per spot ), n=7, correlation coefficient is 0.9990. This method has been applied to the determination of trace mercury in hair and cigarette samples with satisfactory result. The reaction mechanism for formation of the ion association complex is also discussed.