pH-Spectrum of
Citric acid-copper-complex



recorded by Dr. G. Mermigidis

Experimental:

System C05/1/2 - (0.5/1.0/2.0 mmol/L Citric acid / dist. water),
System (C05/1/2+Cu) - (1.0 mmol/L CuCl2 + 0.5/1.0/2.0 mmol/L Citric acid / dist. water),
System (C05/1/2+Cu) - (1.0 mmol/L CuCl2 + 0.5/1.0/2.0 mmol/L Citric acid + 1.0 mmol/L EDTA / dist. water),
System Cu - (1.0 mmol/L CuCl2 / dist. water),
System CS05 - (0.5 mmol/L Sodium Citrate / dist. water),
System (CS05/1/2+Cu) - (1.0 mmol/L CuCl2 + 0.5/1.0/2.0 mmol/L Sodium Citrate / dist. water)









Results:

Fingerprints

System C05/1/2: At the point of intersection of tangents at pH 4.0/3.8/3.5 and 12, 73%/56%/38% and 78% of the COOH-groups from Citric acid have been deprotonated.
System Cu: The forming of Cu(OH)2 between pH 6.5 and pH 11.6 could be shown.
System CS05: The forming of Citric acid between pH 6.4 and pH 2.0 could be shown.

Systemprints

System (C05/1/2+Cu): The forming of 0.5 mmol/L HO-Cu-Citr.-Cu-OH/ 0.5 mmol/L Citr.-Cu-Citr.-Cu-OH/ 0.75 mmol/L Citr.-Cu-Citr. and 0.25 mmol/L Citr.-Cu-OH complex could be postulated.
System (CS05/1/2+Cu): The forming of 0.5 mmol/L HO-Cu-Citr.-Cu-OH/ 0.5 mmol/L Citr.-Cu-Citr.-Cu-OH/ 0.75 mmol/L Citr.-Cu-Citr. and 0.25 mmol/L Citr.-Cu-OH complex in solution could be shown at pH 11.5/11.7 and 11.8.

Systemprint with Additive, helps you to check the influence of an Additive

System (C05/1/2+Cu): The curve of the stable, Cu-EDTA-complex appear, see System (Cu10+E).

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