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. After microextraction process, MWCNTs are collected onto filter and directly measured by EDXRF. With this technique, the direct quantification of metal species held in solid materials is possible and, therefore, the elution step can be avoided. The effects of various experimental parameters such as pH of the solution, amounts of MWCNTs and APDC, sample volume, and time of stirring were investigated. With the best analytical conditions (1 mg of MWCNTs, 2 mg of APDC, 100 mL sample volume, pH = 7, and 5 min time of stirring), Co(II), Ni(II), Cu(II), and Pb(II) can be simultaneously determined with very good recoveries (101%, 98%, 96%, 99%, respectively) and detection limits (0.43, 0.11, 0.46, 0.15 ng mL<sup>-1</sup>, respectively). The method was applied in determination of trace metal ions in tap water and wastewater samples.
You do not have subscription access to this journal. Cited by links are available to subscribers only. You may subscribe either as an OSA member, or as an authorized user of your institution.
Contact your librarian or system administrator
Login to access OSA Member Subscription