Preconcentration by coprecipitation of copper and nickel with Mo(VI)/triazole derivative system and their determinations by flame atomic absorption spectrometry in food and water samples

Abstract

A new separation and preconcentration technique based on coprecipitation of Cu(II) and Ni(II) ions by the aid of Mo(VI)/di-tert-butyl{methylenebis[5-(chlorobenzyl)-4H-1,2,4-triazol-3,4-diyl]}biscarbamate (BUMECTAC) precipitate has been established. The Mo(VI)/BUMECTAC precipitate was dissolved by concentrated HNO 3 and the solution was completed to 5.0mL with distilled/deionized water. The levels of the analyte ions were determined by flame atomic absorption spectrometer. The effects of experimental conditions like HNO 3 concentration, amount of BUMECTAC and Mo(VI), sample volume, etc. and also the influences of some foreign ions were investigated in detail on the quantitative recoveries of analyte ions. The preconcentration factors were found to be 40 for Cu(II) and 100 for Ni(II) ions. The detection limits for Cu(II) and Ni(II) ions based on 3? (N:10) were 0.43 and 0.70µgL -1, respectively. The relative standard deviations were found to be lower than 4.0% for both analyte ions. The accuracy of the method was checked by spiked/recovery tests and the analysis of two certified reference materials (Environment Canada TM-25.3 and CRM-SA-C Sandy Soil C). The procedure was successfully applied to sea water and stream water as liquid samples and baby food as solid sample in order to determine the levels of Cu(II) and Ni(II) ions. The developed method, based on coprecipitation of Cu(II) and Ni(II) ions by the aid of Mo(VI)/BUMECTAC precipitate, offers a simple, rapid, and low cost separation and preconcentration technique for accurate and precise determination of Cu(II) and Ni(II) ions in environmental solid and liquid samples.