TRACE DETERMINATION OF NICKEL BY MICROWAVE-INDUCED PLASMA ATOMIC EMISSION-SPECTROMETRY AFTER PRECONCENTRATION OF NICKEL TETRACARBONYL ON CHROMOSORB

A method is presented for the determination of ultra-trace nickel concentrations in various samples. Ni2+ is reduced in aqueous solution by tetrahydroborate to Ni0, which reacts readily with carbon monoxide to give gaseous Ni(CO)4, the latter being preconcentrated on Chromosorb, cooled by liquid nitrogen. After desorption of the carbonyl by electrically heating the Chromosorb trap, it is swept by argon to the microwave-induced plasma (hollow-cylinder O2-Ar MIP with Beenakker resonator). Using this technique, nickel detection is possible without any interferences, because other carbonyl-forming reactions are too slow. The detection limit is 5 pg (3σ), corresponding to 5 ng l-1, and the relative standard deviation is 3% at 100 pg. The method was applied to sea water and urine without digestion and whole blood, blood serum and human hair after decomposition by HNO3-HClO4. © 1990.