Volatile Acidity Determination - Selecta DE-1626 Manual De Instrucciones

INSTRUCTION MANUAL CODE 80191 REV D JAN/2020
J
.P. SELECTA s.a.u.

12 Volatile acidity determination

12.1 Equipment
Distilling unit DE-1626
Tritation Burette
Kitasatos flask or Ultrasonic bath
Vacuum pump
12.2 Reagents
Saturated solution of borax
Potassium iodide crystallized
Hidrocloric acid (d = 1,8 ó 1,9 g/l)
Tartaric acid crystallized
Sodium hidroxide 0,05N
Fenolftaleine 1%
Iodyne solution 0,005 M ( 0,01N)
Solution Starch paste 5g/l
12.3 Sample preparation
Remove the carbonic gas bubbles from sample by using ultrasonic bath or kitasatos
flask and vacuum pump.
12.4 Distillation
Use the distilation tube 250ml (small one) and add 20 ml sampleon it.
Add about 0.5 g of tartaric acid and start the steam generator.
Distill up to 250 ml on the erlenmeyer flask.
12.5 Tritation
Tritate distilled with sodium hidroxide 0.1M with two drops of fenolftaleine. Con-
sumption will be «V».
12.6 Free SO2 Tritation
Add on the 12.5 tritated solution, 4 drops of hidrochloric acid, and 2 ml de starch
paste and some glasses of Potassium iodide.
Tritate the free SO2 with 0.005 M Iodyne. Consumption will be «V'».
12.7 Combined SO2 tritation
Add the Saturated solution of borax (Around 20ml) up to a pink solution appears.
Tritate with 0.005 M Potasium Iodyne. Consumption will be «V''».
12.8 Calculation
V = NaOH consumption (ml) on tritation paragraph 12.5
V' = Iodyne 0.005M consumption on tritation paragraph 12.6
V'' = Iodyne 0.005M consumption on tritation paragraph 12.7
Volatile acidity (meq/l) = 5 x (V - V'/10 - V''/20)
Volatile acidity (g/l sulphuric acid) = 0.49/2 x (V - V'/10 - V''/20)
Volatile acidity (g/l acetic acid) = 0,3 x (V - V'/10 - V''/20)
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