Figure 4. Effect of equilibration temperature on the cloud point extraction using DFID reagent of copper. Conditions: 15 mL of 0.2 µ g mL -1 Cu 2+ ion at pH 5.7±0.3, 1.5 mM, 0.06 (w/v) Triton X-114, DFID, 0.5 % (w/v) NaCl, eluting solution 0.5 mL of 0.50 M HNO