Dispersive micro solid-phase extraction using multiwalled carbon nanotubes for simultaneous determination of trace metal ions by energy-dispersive X-ray fluorescence spectrometry.

A methodology based on dispersive micro solid-phase extraction (DMSPE) using multiwalled carbon nanotubes (MWCNTs) as solid sorbent prior to measurement with energy-dispersive X-ray fluorescence (EDXRF) spectrometry is proposed. The procedure consists of chelating of nickel, cobalt, copper, and lead ions with ammonium pyrrolidinedithiocarbamate (APDC) and posterior adsorption of metal chelates on MWCNTs (1 mg) dispersed in the aqueous samples (100 mL). DMSPE promotes immediate interaction between the metal chelates and MWCNTs and shortens time of sample preparation in comparison with classical solid-phase extraction.

Carbon nanotubes as a solid sorbent for the preconcentration of Cr, Mn, Fe, Co, Ni, Cu, Zn and Pb prior to wavelength-dispersive X-ray fluorescence spectrometry.

The preconcentration of trace elements on multiwalled carbon nanotubes (MWCNTs) followed by a wavelength-dispersive X-ray fluorescence analysis (WDXRF) has been investigated. The proposed preconcentration procedure is based on the sorption of trace elements on MWCNTs dispersed in analyzed solution. After sorption, the MWCNTs with the metal ions were collected onto the filter, and then the preconcentrated elements were determined directly by WDXRF.