An efficient green microextraction method of Co and Cu in environmental samples prior to their flame atomic absorption spectrometric detection

A dispersive liquid-liquid microextraction procedure (DLLME) was developed and validated for the determination of cobalt and copper in environmental samples by flame atomic absorption spectrometry. The optimisation parameters of DLLME procedure including amount of chelating reagent (0.05 mg dithizone), pH (6), extraction type and volume (250 mu L chloroform) and dispersive solvent (1000 mu L acetone), matrix effect was investigated. Several validation variables, such as limit of detection and quantification, linearity, recovery, precision and trueness were also tested. The quantification limits of Co and Cu were found to be 9.01 and 6.14 mu g L-1, respectively. The enrichment factor was 20. The trueness of the method was tested by analysis of certificated reference material (BCR-715) for Cu and calculated less than -1.11% with the relative error. The presented green microextraction method was profitably applied to real samples and the spiked recoveries calculated were more than 95% with the relative standard deviation less than 8.4%.