DETERMINATION OF NICKEL IN BIOLOGICAL SAMPLES BY INDUCTIVELY-COUPLED PLASMA-ATOMIC EMISSION-SPECTROMETRY AFTER EXTRACTION WITH S[PHENYL-(2-PYRIDYL)METHYLENE]THIOCARBONOHYDRAZIDE

A sensitive inductively coupled plasma atomic emission spectrometric m ethod for the determination of trace amounts of nickel after extractio n of the metal into isobutyl methyl ketone (IBMK) containing is[phenyl (2-pyridyl)methylene]thiocarbonohydrazide (BPTH) is described. A syste matic study was made to determine the optimum conditions for extractio n of the metal into IBMK. The chief advantage of the method lies in th e maximum allowable aqueous-to-organic phase volume ratio of 37. The d etection and quantification limits for nickel were 0.3 and 1.1 ng ml-1 , respectively, and the calibration is linear from 0.4 to at least 150 ng ml-1. The method has been used for the determination of nickel in various biological samples [mineralized by microwave digestion in seal ed poly(tetrafluoroethylene) containers], as well as in human urine, w ith good results.