A new supramolecular based liquid solid microextraction method for preconcentration and determination of trace bismuth in human blood serum and hair samples by electrothermal atomic absorption spectrometry.

A simple and reliable supramolecule-aggregated liquid solid microextraction method is described for preconcentration and determination of trace amounts of bismuth in water as well as human blood serum and hair samples. Catanionic microstructures of cetyltrimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) surfactants, dissolved in deionized water/propanol, are used as a green solvent to extract bismuth (III)-diethyldithiocarbamate complexes by dispersive microextraction methodology. The extracted solid phase is easily removed and dissolved in 50 μL propanol for subsequent measurement by electrothermal atomic absorption spectrometry (ET-AAS). The procedure benefits the merits of supramolecule aggregates' properties and dispersive microextraction technique using water as the main component of disperser solvent, leading to direct interaction with analyte. Phase separation behavior of extraction solvent and different parameters influencing the extraction efficiency of bismuth ion such as salt concentration, pH, centrifugation time, amount of chelating agent, SDS:CTAB mole ratio, and solvent amounts were thoroughly optimized. Under the optimal experimental conditions, the calibration curve was linear in the range of 0.3-6 μg L-1 Bi (III) with a limit of detection (LOD) of 0.16 μg L-1 (S/N = 3). The relative standard deviations (RSD) of determination were obtained to be 5.1 and 6.2 % for 1 and 3 μg L-1 of Bi (III), respectively. The developed method was successfully applied as a sensitive and accurate technique for determination of bismuth ion in human blood serum, hair samples, and a certified reference material.