Solid-phase extraction (SPE) of Ni(II), Cd(II) and Pb(II) ions using pyromellitic dianhydride functionalized silica gel prior to flame atomic absorption spectrometric determination
Elem Efe, Mustafa İmamoğlu
Abstract
In this work, a novel pyromellitic dianhydride modified silica gel (PMDA-SG) was firstly fabricated for column solid-phase extraction (SPE) of Ni(II), Cd(II), and Pb(II) ions at trace levels from aqueous solutions, aiming to determine their trace level using flame atomic absorption spectrometer. PMDA-SG was confirmed by FT-IR and C,H,N elemental analysis. Optimization of the SPE column for Ni(II), Cd(II) and Pb(II) ions using the PMDA-SG loaded column involved a comprehensive investigation of the key factors. The optimum conditions were found as follows: a sample solution pH of 7.0, a sample flow rate of 5 mL/min, a maximum solution volume of 500 mL, and an eluent consisting of 5 mL of 1.0 mol L−1 HNO3 solution. To validate the developed SPE method, a certified reference material of Ontario Lake water (NWTMDA-54.4) was employed, and a good fit was observed in the obtained data. The SPE method demonstrated good precision in the determination of Ni(II), Cd(II) and Pb(II) at 20 ng mL−1 (n = 5), yielding relative standard deviation values lower than 5%. Trace levels of Ni(II), Cd(II) and Pb(II) in environmental water samples form laboratory tap, Sapanca Lake, Çark Stream and Sakarya River were successfully quantified by FAAS after preconcentration using PMDA-SG filled column.