Bone tissue contains water (50%), organic (28%) and inorganic (22%) substances. Among the latter, most part is calcium phosphate (85%); in much smaller quantities it containes calcium carbonate (10%), magnesium phosphate (1,5%) and calcium fluoride (0,3%). Inorganic substances of dental tissues are represented mainly by hydroxyapatite [Ńą3ŠĪ4)2]3 Ńą(ĪĶ)2.
Preparation of extracts of bone and teeth tissues.
Put 5 g of bone tissue in the flask, pour 25 ml of 0,5% sulfuric acid solution and leave for a day. Inorganic substances transfer into solution. Extract is filtered.
A sample of 0.5 g of the tooth is placed in a flask. Add 30 ml of 10% hydrochloric acid solution and boil in the ventilating box. When a tooth is completely dissolved, the flask contents is cooled and filtered.
2. The detection of calcium ions.To 2 ml of extract 3-4 drops of a saturated solution of ammonium oxalate was added. Calcium oxalate is precipitated:
3. The detection of magnesium ions. Calcium oxalate obtained in the previous experiment, isolated by filtration. Add 3-4 drops of concentrated ammonia solution to the filtrate. There is a precipitate of magnesium ammonium phosphate:
MgHPO4 + NH4OH ® MgNH4PO4¯ + H2O
4. The detection of phosphoric acid. To a few milliliters of the filtered extract 5 6 drops of molybdenum reagent is added and heated to boiling. Slowly, a yellow crystalline precipitate of ammonium phosphomolybdate is forming: