Separation and determination of cadmium in water samples based on functionalized carbon nanotube by syringe filter membrane-micro solid-phase extraction

A simple and fast separation of cadmium (Cd) based on functionalized carbon nanotubes with ۲,۳-dimercapto-۱-propanol (CNTs@DHSP) was achieved in water samples before a determination by atom trap flame atomic absorption spectrometry (AT-FAAS). In this study, Cd(II) ions were extracted by syringe filter membrane-micro solid phase extraction procedure(SFM-μ-SPE). Firstly, ۲۰ mg of the CNTs@DHSP as solid-phase added to ۲۰ mL of water sample in a syringe, then dispersed for ۳ min after adjusting pH up to ۷ and pass through SFM very slowly. After extraction, the Cd(II) ions were back-extracted from SFM/CNTs@DHSP by ۱.۰ mL of eluent in acidic pH. Finally, the cadmium concentration was measured by AT-FAAS. Under the optimal conditions, the linear range (۲–۹۰ μg L−۱), LOD (۰.۷۵ μg L−۱) and enrichment factor (۱۹.۶) were obtained (RSD<۱.۵%). The adsorption capacity of Cd(II) with the CNTs@ DHSP was obtained about ۱۵۲.۶ mg g-۱. The method was validated by certified reference materials (SRM, NIST) and ET-AAS in water samples.

Keywords:

Cadmium , Separation , Water , Functionalized carbon nanotubes , Syringe filter membrane micro solid phase extraction , Atom trap flame atomic absorption spectrometry