Preconcentration procedure trace amounts of palladium using modified multiwalled carbon nanotubes sorbent prior to flame atomic absorption spectrometry

摘要

A method for preconcentration of palladium at trace level on modified multiwalled carbon nanotubes columns and determination by flame atomic absorption spectrometry (FAAS) has been developed. Multiwalled carbon nanotubes (MWCNTs) were oxidized with concentrated HNO3 and the oxidized multiwalled carbon nanotubes were modified with 5-(4'-dimethylamino benzyliden)-rhodanine, and then were used as a solid sorbent for preconcentration of Pd(II) ions. Factors influencing sorption and desorptioh of Pd(ll) ions were investigated. The sorption of Pd(II) ions was quantitative in the pH range of 1.0-4.5, whereas quantitative desorption occurs with 3.6 mL 0.4 mol L~(-1) thiourea. The amount of eluted palladium was measured using flame atomic absorption spectrometry. The effects of experimental parameters, including sample flow rate, eluent flow rate, and eluent concentration were investigated. The effect of coexisting ions showed no interference from most ions tested. The proposed method permitted a large enrichment factor (about 200). The relative standard deviation of the method was ±2.73% (for eight replicate determination of 2.0 μ g mL~(-1) of Pd(II)) and the limit of detection was 0.3 ng mL~(-1). The method was applied to the determination of Pd(ll) in water, road dust, and standard samples.