Determination of cobalt in water samples using solidified floating organic drop microextraction coupled with graphite furnace atomic absorption spectrometry

A simple, rapid and inexpensive method of the solidified floating organic drop extraction (SFODME) technique coupled with graphite furnace atomic absorption spectrometry (GFAAS) has been developed for the determination of cobalt in water samples. 8-Hydroxyquinoline was used as a complex agent and 1-undecanol was used as the extraction solvent. The factors, including solvent types, solution pH, extractant volume and interfering ions, were investigated and optimised. Under the optimum conditions, the calibration graphs were linear in the range 0.05-10.0 ng mL(-1) cobalt, the limit of detection was 0.02 ng mL(-1), the limit of quantification was 0.05 ng mL(-1) and the relative standard deviation for 10 replicate measurements of 3 ng mL(-1) cobalt was 2.8%. The proposed method was successfully applied for the determination of cobalt in different water samples and the results were satisfactory.