Flame Atomic Absorption Spectrometry Determination of Palladium After Preconcentration Using Modified Multiwalled Carbon Nanotube Sorbent

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 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol, and then were used as a solid sorbent for preconcentration of Pd(II) ions. Factors influencing sorption and desorption of Pd(II) ions were investigated. The sorption of Pd(II) ions was quantitative in the pH range of 5 to 9, whereas quantitative desorption occurs with 4.0 mL of 1.0 M HCl and then 3.0 mL 1.0 mol L-1 thiourea. The amount of palladium which eluted 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 100). The relative standard deviation of the method was ±2.5% (for eight replicate determination of 3.6 μg mL-1 of Pd(II)) and the limit of detection was 5.0 ng mL-1.

Keywords:

Carbon nanotubes application , Preconcentration , Palladium determination