Hydrogen peroxide is used in all of the following chemical tests for blood except:
A. Benzidine test
B. Phenophthalein test
C. Orthotolidine test
D. Teichmann’s test
Correct answer : D. Teichmann’s test
Benzidine test, phenolphthalein test, orthotolidine test and Leucomalachite green test utilise hydrogen peroxide to detect presence of blood. Hemoglobin present in blood is a peroxidase. It oxidises colourless bases to coloured salts in the presence of hydrogen peroxide.
Teichmann’s test (haemin crystal test) is done by converting haemoglobin to haemin crystals which is converted to salt in the presence of halogen and forms rhombic crystals.