Spectrophotometric Determination of Trace Amount of Nickel(II) in Tea Leaves Sample by Using Antipyriyl azo-2,7-naphthalendiol as New Reagent

A new, simple, sensitive and rapid spectrophotometric method is proposed for the determination of trace amount of nickel(II).The method is based on the formation of a 1:2 complex with 1-(4 ′ -pyrazolon azo) 2,7-naphthalendiol (1-APANDOL) as a new reagent is developed .The complex has a maximum absorption at 514 nm and ε max of 2.0x10 4 L mol -1 cm -1 .A linear correlation (0.1-2.0 μg mL -1 ) was found between absorbance at λ max and concentration.The accuracy and reproducibility of the determination method for various known amounts of nickel(II) were tested.The results obtained are both precise (RSD was better than 0.63%) and accurate (relative error was better than 0.2%).The effect of diverse ions on the determination of nickel(II) to investigate the selectivity of the method were also studied.The stability constant of the product was 0.13x10 8 L mol -1 .The proposed method was successfully applied to the analysis of synthetic mixtures and tea sample without any preliminary concentration or separation.