Sequential multi-element determination of iron and zinc in water samples by high-resolution continuum source graphite furnace atomic absorption spectrometry after column solid-phase extraction onto multiwalled carbon nanotubes

摘要

A method for the sequential multi-element determination of iron and zinc in water samples by high-resolution continuumsource graphite furnace atomic absorption spectrometry (HR-CS GFAAS) after column solid-phase extraction ontomultiwalled carbon nanotubes (MWCNTs)was described. The influences of someanalytical parameters (including pH of the sample solution, amount of MWCNTs, flow rate of sample, concentration and type of eluent, maximum sample volume and coexisting ions) were investigated for optimization of the proposed procedure. The concentration limits of detection were 4 and 0.5 ng L~(-1) for Fe and Zn, respectively; the preconcentration factors achieved for Fe and Zn were 25 and 20, respectively. The relative standard deviations (RSDs) were 6% and 4% for Fe and Zn, respectively. The accuracy of this method was validated by analyses of NIST SRM 1643e (Trace Elements in Water) and ERM — CA011b (Hard Drinking Water) certified reference materials. The measured element contents in these reference materials were in satisfactory agreement with the certified values according to the t-test for a 95% confidence level. The presentedmethod has been successfully applied for the determination of iron and zinc in four different water samples (seawater, lake water, minewater and tap water).