Enrichment and determinations of nickel(II), cadmium(II), copper(II), cobalt(II) and lead(II) ions in natural waters, table salts, tea and urine samples as pyrrolydine dithiocarbamate chelates by membrane filtration–flame atomic absorption spectrometry combination

Abstract

A membrane filtration procedure for the preconcentration of nickel(II), cadmium(II), copper(II), cobalt(II) and lead(II) ions has been established. The analytes were adsorbed on cellulose nitrate membrane filter as their ammonium pyrrolydine dithiocarbamate (APDC) complexes. Then membrane filter was dissolved by using nitric acid. The levels of the analytes in the final solutions were determined by flame atomic absorption spectrometry (FAAS). The analytical parameters including pH, amounts of APDC, sample volume, matrix effects, etc. have been optimized. The present method has been successfully applied for the FAAS determinations of analyte ions in a stream sediment reference material (GBW 07309), table salts and natural water samples with good results, e.g. recoveries greater than 95%, relative standard deviations generally lower than 9%. The analyte ion levels of the microwave digested urine and black tea samples were also analyzed by using proposed preconcentration procedure.