Résumé:
The inhibition of the calcbium oxalate crystallization is investigated using a turbidimetric model by
means of a UV/VIS spectrometer. The turbidity of thermostatic solution at 37° C under constant agitation
is measured at 620 nm. The solutions concentrations of calcium chloride CaCl
2
and sodium oxalate
C
2
O
4
Na
2
in the test were respectively 4 and 0.5 mmol.L
-1
. The investigated inhibitors were magnesium
ions between 2.10
-1
et 7 mmol.L
-1
, citric acid between 10
-3
et 4 mmol.L
-1
, fluoride between 1 et 12
mmol.L
-1
and ferrous ion between 0.1 and 0.4 mmol.L
-1
. We have used physiologic concentrations in
order to work near the best conditions of calculus formation. The rates of inhibition obtained from the
turbidimetric slopes with and without inhibitors were measured as a mean of 6 experiments. The CV
observed were at 5% lower. The effect of these i
nhibitors on the crystallization phases has been followed
with an optical microscope photography with a polarised light. The results at the used observation scale
showed that the magnesium act the nucleation and the
aggregation; citric acid on the three crystallization
phases (nucleation, crystalline growth and aggregation) and finally fluoride and ferrous ions on the
nucleation and crystalline growth.
