Velp Scientifica
– UDK139 Operating Manual
10004762/B5
109
of sodium thio-sulphate and 1ml of solution of ammonic ferric sulphate. If salycilic acid is
present a violet colour will appear.
-dosage of the salycilic acid:
In the flask described above mark the level of the distillate volume. Empty the flask and
wash it. Distill a new sample aliquot of 20ml of wine and collect the distillate in the flask
filling it up to the level mark. Add 0.3ml of hydrochloric acid and 1ml of solution of
ammonic ferric sulphate. The liquid in the flask will turn violet. Pour in a flask ,equal to the
flask with the level mark, some distilled water up to the same distillate level. Add 0.3ml of
hydrochloric acid and 1ml of solution of ammonic ferric sulphate . Add by a burette the
solution of sodium salycilate 0.01M ,until a violet colour is obtained, having the same
intensity of the colour in the flask containing the wine distillate. Being
n’’’
the used ml.
-correction of the volatile acidity:
subtract 0.1 x
n’’’
ml from the volume of
n
ml of solution of sodium hydroxide 0.1M used
to titrate the distillate acidity during the dosage of the volatile acidity.
References
: EEC Reg. n. 266/90 , 17 Sept. 1990, determining the methods to be used for
the analyses in the wine sector.
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