Dispersive liquid-liquid microextraction of trace amounts of molybdenum prior to electro-thermal atomic absorption spectrometry determination

In the present work, dispersive liquid-liquid microextraction method has been developed for preconcentration trace amount of molybdenum ion as a prior step to its determination by electro-thermal atomic absorption spectrometry. In the proposed approach, quin alizarin was used as a chelating agent and carbon tetrachloride and ethanol were selected as extraction and dispersive solvents, respectively. Some effective parameters on complex and extraction formation, such as the extraction and dispersive solvent type and volume, pH of sample solution, kind of chelating agent, centrifugation rate and time and salting out effect were studied and optimised. The calibration curve was linear in the range of 0.5-9.0ng mL(-1) with detection limit of 0.02ng mL(-1) (n=8). The relative standard deviation was +/- 2.9% (n=8, C=4.0ng mL(-1)) and the enrichment factor was 200. The proposed method was applied for determination of molybdenum in different water samples.