Preconcentration-Separation of Heavy Metal Ions in Environmental Samples by Membrane Filtration-Atomic Absorption Spectrometry Combination

Abstract

The preconcentration performance characteristics of cellulose nitrate membrane filter were investigated for the atomic absorption spectrometric determinations of traces metal ions in the environmental samples. The method was optimized for several parameters, including buffer pH, matrix, and type of the membrane. The investigated analyte ions were collected on cellulose nitrate membrane filter as their 8-hydroxyquinoline (8-HQ) (oxine) complexes. Then membrane filter was dissolved by using small amounts of concentrated nitric acid. The levels of copper, iron, cobalt, and cadmium ions in the final solutions were determined by flame atomic absorption spectrometry (FAAS). The recoveries of analytes were generally in the range of 94-102%. No influences have been observed from the matrix of the natural water samples. The presented procedure was applied for the determinations of analyte ions contents of natural waters, some ammonium salts, and microwave digested black tea samples with satisfactory results. The relative standard deviations of the determinations were below 9%. The method was verified by the analysis of two reference standard materials (GBW 07309 stream sediment and NRCC-SLRS-4 Riverine Water).