Determination of Trace Nickel by Spectrophotometry with 2,2′,4,4′-Tetrahydroxybenzophenone as Ligand

Spectrophotometry was applied to the determination of trace Ni2+ with 2,2′,4,4′-tetrahydroxybenzophenone (BP-2) as a ligand. In the buffer solution of H3BO3-KCl -NaOH (pH 9.80), Ni2+ reacted with BP-2 at 60 ℃ for 20 min to form a complex, which displayed the maximum adsorption at the wavelength of 434 nm with the molar absorptivity of 2.025×104L·mol-1·cm-1. A linear relationship was found between the absorbance and the mass concentration of Ni2+ in the range of 0.20-23.0 mg·L-1, with detection limit (3S/N) of 0.17 mg·L-1. Recovery rates obtained by standard addition method were in the range of 99.3%-103% and RSDs (n=6) were within 1.1%. The proposed method was used to determine Ni2+ in waste solution, the relative error was -0.98% compared with AAS.