What is a urine albinum test?

Urine Albinum Test

In forensic testing, urine albinum test is used for the detection of mercury. Mercury is an extensively used metal in several industrial processes such as gold refining, amalgam fillings and batteries. It can cause both acute and chronic intoxication. Chronic exposure can lead to central and peripheral nervous system damage.

Principle

This method is mainly based on the interaction of mercury with iodine which produces yellow precipitate of dimercuri-ammonium-iodide. Then the precipitate undergoes reduction to yield black-grey amorphous mass.

Procedure:

1. A small portion of the urine sample is placed into a test tube and is gently heated.

2. To this warmed sample, a few drops of saturated iodine in potassium iodide are added.

3. The mixture is again gently heated for 2-5 minutes.

4. A black-grey amorphous mass is produced.

5. If no precipitate or yellow precipitate (HgI2) appears on the heating of urine sample, it indicates the absence of mercury.

6. If yellow precipitate is observed, then it is reduced by gently heating the mixture with nitric acid.

Limitations:

The urine albinum test has some limitations. It can be affected by the presence of other substances in urine, such as proteins and reducing substances. This can lead to false positive or false negative results.

Significance

The presence of mercury in urine is a reliable index of exposure to mercury and also indicates kidney damage by mercury.