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Instruction Manual Mi455 FREE & TOTAL SULPHUR DIOXIDE Minititrator for wine analysis
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GENERAL DESCRIPTION
The
Mi455
is a low-cost, easy to use, microprocessor-based automatic titrator. It has a
simple and reliable peristaltic pump that ensure high dosing repeatability. By performing
pump calibration with the provided Milwaukee standards, the instrument accuracy is assured.
The instrument comes with a pre-programmed analysis method designed for Free and
Total Sulphur Dioxide measurements on wine samples. The instrument has a powerful
and effective built-in algorithm to analyze the shape of the electrode response and to
determine the reaction completion. This algorithm automatizes the analysis, makes all
the necessary calculations and assures a simple and effective interface for the user.
By simply pressing the START STOP button, the instrument will automatically make the
titration up to the equivalence point. The result is immediately displayed in convenient
units, then the instrument is ready for another titration.
SIGNIFICANCE OF USE
An important reason for adding SO
2
is to avoid oxidation. When there is oxygen around,
SO
2
itself becomes oxidized before phenol compounds in the wine , and so acts as an oxygen
scavenger. Also SO
2
suppresses the activity of enzymes that cause browning and other
problems.
What is really protecting your wine is molecular SO
2
. When you add SO
2
, depending of
circumstances, some of it immediately becomes bound. The relationship between the
amount of added SO
2
and the amount of SO
2
remaining free is complex. It is clear,
however, that it is largely governed by the total SO
2
content of the wine. The rate of binding
decreases as the free SO
2
concentration increases. The exact relationship between free
and bound (total - free) SO
2
will vary from wine to wine.
Below 30-60 ppm, 33% to 50% of SO
2
addition becomes bounded. What remains is
called “free” and it is divided in two parts. The larger, and relatively ineffective free part is
KEYPAD
A. PUMP - to start/stop the pump
B.
CAL - to enter pump calibration mode
C. STIR - to start/stop the stirrer while in
measurement or purging mode
D. START STOP - to start/stop titration or
pump calibration