The extraction of trace ;cobalt, copper, nickel, cadmium, lead and zinc in urine c aI a}.
samples of organic and alkali metal matrix into chloroform by the complex with a dithizone ~} x´01 0
was studied for graphite furnace AAS determination. Various experimental conditions´ such :Zo 0 4
as the pretreatment of urine, the pH, of sample solution, and dithizone concentration in ,, L o}´ti o}
solvent were optimized for the effective extraction, and some essential conditions were also
studied for the back-extraction and digestion as well. All organic materials in 100 mL urine 6 18,
were destructed by the digestion with conc. HNO3 30 mL and 30% H202 50 mL. Here, H_0, - 1 } -Tr- t
was added dropwvise with each 5.0 mL, serially. Analytes were extracted into 15.0 mL
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