The pH of the solution plays a unique role on metal-chelate formation
and the subsequent extraction. The extraction yield
depends on the pH at which the complex formation occurs. In
the present work DLLME-SFO was performed at different pH values,
in the range 3–8. The results demonstrated in Fig. 1 reveal that
the highest extraction recovery was obtained at the pH of 6.0.
Hence, the pH of 6.0 was chosen for the subsequent extractions
and real sample analysis.