Uribilin is an oxide products of urobilinogen when urobilinogen undergo oxidation reaction. Urobilins is orange coloured and are responsible for the normal colors of the urine, whereas urobilinogen is colourless. Urobitin does not react wsth Ebrlich’s reagent, but reacts with Schle- singer’s zinc acetate reagent.
Schlesinger’s Test for Urobilin (Urobilinogen Unobillin)
Principles Urobilinogen is oxidised to urobilin with tincnure of iodine When mixed with alcoholic zinc acetate solution, zinc-urobilni is formed which shows a gneen fluorescence.
- Tincture of iodine: Prepare a saturated solation of iodine in 70 % ethanol
Zine acetate reagent: Prepare a saturated solution of zinc-acetate in absolute ethanol
1.To about 10 ml of urine in a test tube add few drops of tincture of iodine
2 In another test tube, place about 10 ml zinc-acetate reagent.
- Mix the two solutions by pouring from one to another backward and forward several times (10 – 12 times)
Filter the mixed solutions through whatman number 1 filter paper.
Examine the filtrate for green fluorescence by giving from above against a dark background and passing through the directory of a fairly strong light. the fluorescent is more easily detectable on the ultraviolet light.
Result: normal urine give a very mild fluorescence the test is reported as positive, negative or increased.
1 bilirubin’s if present, must be removed from the urine as for the urobilinogen test.
- The test can be performed for the directions of european only if the first step of excitations with iodine is removed.