A PerkinElmer model AAnalyst 800 flame atomic absorption spectrometer (Norwalk, CT, USA) equipped with a deuterium background correction system and an air-acetylene burner was used for the determination of metal ions. Spectral bandwidth of 0.7 nm, acetylene flow rate of 1.4 L min−1, and nebulizer flow rate of 10.0 mL min−1 were conventional working parameters. For measuring pH values in the aqueous phase, a Consort model C533 pH meter combined with a glass-electrode and also a magnetic stirrer (Chiltern) were used.