Abstract: This paper illustrated a new method of catalytic fluorescence determination of trace Cu(Ⅱ) in foodstuffs.In pH8.2～9.2 NH4-NH4 Cl buffer medium the reaction of Cu(Ⅱ) to Rh B and H2O2 took strong catalytic effect to quench the fluorescence.Being quick and easy to operate,the method showed extremely high sensitivith,with the detection limit as 4×10-12g/ml and thelinear range as from 10-11 to 10-6g/ml.The reagent was stable with small consumption.The relative standard deviation for determiningtrace Cu(Ⅱ) in the five kinds of foodstuffs was less than 5%,with a recovery rate between 94.1% to 103%.

Key words: copper, Rh B-H2O2, catalytic fluorescence, foodstuffs