Abstract: In (CH2)6N4-HCl(pH5.8), buffer nickel(II)-3-thiazolyazo-5-amino phenol complex causes a sensitive polaro- graphic wave at the potential of -440 mV(vs. SCE). The 2nd-order derivative peak current was linear with nickel(II) concentration in the range of 0.05～7.00μg/ml (r=0.9992, n=10) with a detection limit of 0.02μg/ml. The recovery was between 95.0% ～103.5%. Several electrochemical methods are used to study the properties of the wave. It is proved to be an adsorptive wave of the nickel complex. The electrode process is an irreversible process, and the number of electron transfer is 2. The interference of diverse ions on the peak current was investigated. The proposed method has been applied to determine trace nickel in beverage and fruit with a satisfactory result.

Key words: 3-thiazolyazo-5-amino phenol complex, adsorptive wave, nickel, beverage and fruit