Preconcentration of mercury on polyaniline expands the horizon for energy dispersive X-ray fluorescence determination

Hg(II) was sorbed on polyaniline from aqueous solutions, followed by determination using energy dispersive X-ray fluorescence spectrometry. Distribution coefficient of Hg(II) on polyaniline was about 4x10(3) in water, whereas distribution coefficient was 1.2x10(4) at 0.1M HCl and decreased drastically with increase in HCl concentration. Rapid kinetics of sorption was evinced by the 80% uptake within the initial 1min and quantitative sorption within 5min of equilibration. The sorption was found to follow Langmuir isotherm model, and the Langmuir capacity was calculated as 19.7mgg(-1). The ability of polyaniline to form stable and homogeneous pellets facilitated the energy dispersive X-ray fluorescence determination without recourse to elution. Detection limit of Hg was found to be 22ng, considering 100mg pellet of polyaniline. The apparent detection limit was 6pg, as the preconcentration factor of Hg(II) on polyaniline was 4x10(3). The developed method is at par with the established method for mercury determination, namely, cold vapor atomic absorption spectrometry. Accuracy of the method was established by the analysis of the International Atomic Energy Agency reference materials, namely, hair and lichen, for Hg(II). Copyright (c) 2016 John Wiley & Sons, Ltd.