a new dispersive liquid-liquid microextraction method followed by direct gf-aas determination optimized with experimental design and response surface methodology for determination of ag(i) in water samples

in this research, a rapid, reliable and selective dispersive liquid-liquid microextraction (dllme) followed by direct injection of microdroplet to graphite furnace atomic absorption spectrometry (gf-aas) method for the determination of ultra-trace amounts of ag(i) was developed. effect of the important experimental parameters on the extraction efficiency of ag(i) was investigated using response surface methodology (rsm) by performing a central composite design (ccd). a newly synthesized calixarene (mesotetraspirocyclohexylcalix[4]pyrrole, tscc4p) was utilized as the chelating agent. the optimal experimental condition was obtained as sample volume: 5 ml, dispersive solvent type: methanol, dispersive solvent volume: 715 μl, extracting solvent: 1,2-dichlorobenzene, volume of extracting solvent: 25 µl, amount of tscc4p: 127.1 µg, and ph of sample solution: 6.5. under the optimum conditions ag(i) ions were extracted into a fine sedimented microdroplet, which 10 µl of it was directly injected into gf-aas system. the calibration graph was linear over the range of 0.1-10.0 ng ml-1 with a detection limit (s/n = 3) of 0.02 ng ml-1. the relative standard deviation (rsd%) for ten replicated determinations of 10 ng ml-1 ag(i) was 3.1%. the enrichment factor and extraction recovery were found to be 292 and 96%, respectively. the proposed dllme-gf-aas method was successfully applied to the extraction and determination of ag(i) ions in different real water samples.