EXTRACTION-SPECTROPHOTOMETRIC DETERMINATION OF NICKEL AT MICROGRAM LEVEL IN WATER AND WASTEWATER USING 2-[(2-MERCAPTOPHENYLIMINO)METHYL]PHENOL

An extraction-spectrophotometric method for determination of nickel at sub ppm level using 2[(2-mercaptophenylimino)methyl]phenol (MPMP) as the new extractant is described. The reagent reacts with nickel(II) at pH > 10 and form a 1:2 brown complex, which is extracted into chloroform. The complex has a maximum absorption at 421 nm with the molar absorptivity of 2.41 x 10(5) W cm(-1). Beer's law is obeyed over the range of 0.011-0.30 mu g mL(-1). The Sandell's sensitivity for 0.001 absorbance unit is 5.34 x 10(-4) mu g cm(-2). The relative standard deviation at 0.018 mu g mL(-1) is 1.1 % (n = 8), The procedure was successfully applied to determination of nickel in wastewater and standard alloy and the accuracy was determined by recovery experiment, independent analysis by furnace-AAS, and analysis of a certified reference martial.