Rapid and simultaneous analysis of heavy metal ions in aqueous solutions using pre-concentration with dispersive liquid-liquid micro-extraction and X-ray fluorescence detection

A pre-concentration method coupled with dispersive liquid-liquid micro-extraction(DLLME) and X-ray fluorescence(XRF) detection have been established for the determination of heavy metals ions(Pb2+,Cd2+,Hg2+) in aqueous solutions.In the method,firstly,using sodium diethyldithiocarbamate as the complexing agent,heavy metal ions(Pb2+,Cd2+,Hg2+) in aqueous solutions and the complexing agent could form the metal complexes simultaneously at pH 4.0.Then the metal complexes containing target metal compounds were pre-concentrated by DLLME with enrichment factors of more than one hundred,and detected with a XRF detector.It took several minutes to finish the analytical process.The detection limits of heavy metal ions(Pb2+,Cd2+,Hg2+) were 0.1 mg/L.The method can improve the detection limit of XRF,and expand the further application for trace amounts of heavy metal ions(Pb2+,Cd2+,Hg2+) in aqueous solutions.