A spectrophotometric procedure for the determination of Nickel (??) based on the
complex formation with 6-phenyl-2, 3-dihydro-as-triazine-3-thione (PDTT) was
developed. A yellow compound forms and is easily extractable by chloroform at
pH>6. The mole ratio between Nickel (??) and PDTT is 1:4. The absorbance of the
complex obeys Beer's law over the concentration range of 1-7 ug of Ni (??) per ml
chloroform. This procedure can be carried out in the presence of many cations and
anions without appreciable interference.