Legal sample
The Legal sample is used to detect CH-acidic compounds. In clinical analysis, the sample is used to detect acetone in a urine sample .
execution
A solution of sodium pentacyanonitrosyl ferrate (II) {Na 2 [Fe (CN) 5 NO]} is added to a sodium hydroxide-containing solution of the sample. In the presence of a CH-acidic one , the sample turns red.
The Legal test is positive for compounds such as acetone , acetaldehyde , acetoacetic acid and creatinine . Acetic acid can be added to the red colored sample to differentiate between acetone and creatinine . Without acetone, the liquid will fade and later turn green, then blue. However, if acetone was present, the solution will take on an even more intense red color when the acetic acid is added.
Explanation
The proof is based on the complexation of sodium pentacyanonitrosyl ferrate (II) with acetone as a new ligand . First there is alkaline hydrolysis , followed by aldol addition . The red dye complex is created.
causes
Causes of the presence of acetone in the urine can include: B. fasting, starvation, in the context of diabetes mellitus , in acetoneemic vomiting and hypochloraemic syndrome. In these conditions there is an increased formation of ketone bodies , such as acetone. Acetone can then be found in the blood, urine and exhaled air.
swell
- Methods of investigation in organic chemistry (PDF), University of Pécs website