LABEC M-MIA-CC - Manual (Page 85)

Ultrasonic milk analyser
Operation manual 23.08.10 83/98
- Use fresh buffers for calibrations. Avoid contamination of the stock buffer
solution and do not use it beyond the expiry date.
- Keep all connections dry.
- Immerse the electrode far enough into the solution to insure the
reference junction is below the surface.
- Allow adequate time for the electrode to stabilize in standards and
samples before taking a reading.
- Clean the electrode periodically. Allow more time for aged electrodes.
- Do not use the pH electrode in solutions of fluoride ion at low pH. This
will etch the glass membrane.
- Sulphide vapors can permeate the electrode wick and contaminate the
reference element. Minimize contact in such environments and change
the reference electrolyte frequently.
Milk acidity and рН
In the table below the connection between pH value and acidity in °T is
shown
°T deviation рН
average
value
°T deviation рН
average value
Raw milk Pasteurized milk
16 6,74-6,70 6,72 16 6,68-6,64 6,66
17 6,69-6,65 6,68 17 6,63-6,58 6,61
18 6,64-6,58 6,62 18 6,57-6,52 6,55
19 6,57-6,52 6,55 19 6,51-6,46 6,49
20 6,51-6,46 6,49 20 6,45-6,40 6,43
21 6,45-6,40 6,43 21 6,39-6,35 6,37
22 6,39-6,35 6,37 22 6,34-6,30 6,32
23 6,34-6,30 6,32 23 6,29-6,24 6,26
24 6,29-6,24 6,25 24 6,23-6,19 6,21