Aqueous Two-phase Extraction of Trisodium Salt of Copper (II) Chlorophyllin

Ahat SALI, Yoshifumi AKAMA* and Shigeyuki TANAKA

Department of Chemistry, Faculty of Science and Engineering, Meisei University; 2-1-1 Hodokubo, Hino-shi 191-8506 Japan

Aqueous two-phase system formed by mixing (NH4)2SO4 and tetrabutylammonium bromide (TBAB) has been applied to the gentle separation of trisodium salt of copper (II) chlorophyllin (CuCL-Na). An aqueous two-phase system was obtained as follows: to a 3.0 mL of 1.0 mol/L TBAB aqueous solution, 1.0 mL of CuCL-Na aqueous solution containing less than 0.30 mg of CuCL-Na, 1.0 mL of pH 8 buffer solution and 1.1 g of (NH4)2SO4 were added and the mixture was shaken for 1 min, then left at room temperature for 3 h. A 0.5 mL portion of the top phase was diluted to 10 mL with water and its absorbance was then measured at 405 nm against a reagent blank similarly prepared.
The CuCL-Na can be quantitatively extracted into the TBAB-rich upper phase at the wide pH range. It was considered that the extractable species was an ion pair complex of the type CuCL-TBA.

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