A new method for determination of Nickel using 2-(8 -hydroxy quinolino-5-sulfoacid-7-azo)-1,8-dihydroxy-3,6-naphthalene disulfoacid is set u p. In pH9.37 B-R media ,Nickel and 8Q5SAC react to form a 1∶3 complex, and surface active agen t CTMAB has effect of increasing sensitivity. The maximum absorbance of the reagent is 692 nm, th e complex is 542 nm, and the apparent molar absorptivity is 6 0×10 4L·mol -1 ·cm -1 , by using dual wavelength increasing sensitivity method. Beer’s law is obeyed by in 0～20 μg/25 mL for Nickel. The sensitivity increased by 2 5 times in contrast with using single w alvelength. The method is applied to the determination of Nickel in actual sampl es with satisfactory results.
