DETERMINATION OF TRACE NICKEL WITH SECOND ORDER DIFFERENTIAL A. C. OSCILLOPOLAROGRAPHY

A new and convenient method for the rapid determination of trace amounts of nickel in waste solution obtained by cleaning diamond with HNO3 using second order differential a. c. oscillopolarography in 0.20 mol/L NH4Ac–0.005 mol/L KNO3–0.02% diacetyldioxime solution is described in this paper. Experimental conditions were optimized including component and concentration of base solution, the area of hanging mercury drop electrode, the intensity of direct current and alternative current and so on. The calibration graph is linear from 3 × 10-7 to 3.5 × 10-6 mol/L with a detection limit of 6 × 10-8 mol/L. The relative standard deviation of the method is 1.2% for 1.8 × 10-6 mol/L Ni2+. Compared with polarographic analysis and other techniques, the main advantages of the technique are cheap equipment, rapid measurement, high sensitivity and good adaptability for analysis of airsaturated samples.