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12. 2-point (optionally 3-point) calibration
12.1 Preparing the water activity measuring chamber
Preparation
To ensure proper results it is essential that the components of the calibration
equipment have approximately the same temperatures. The best way to do
that is to leave the calibration components at room temperature (+20°C to
+26°C) for at least 60 minutes (or more if you have time available).
Temperature must be between 20°C and 26°C.
The best way to ensure the same temperature of the different components is
to store all components together in a room with only small temperature
fluctuations ideally overnight (even better if done for 24 hours).
Components of calibration equipment
Aw Salt Standard Solutions (0.754
saturated solution in screw-top Nalgene Jar,
0.500
and
0.800
solutions
in
vials),
C a l i b r a t i o n J a r ( Container jar with sponge
base), Screw-Top Nalgene jars, RH2 Water
Activity (Aw meter) and measuring chamber
(Sensor).
Precaution:
0.754 Aw saturated salt standards are
reusable and should be used as it is supplied
along with the jar. It is not meant for pouring
into any other containers.
Please note the Aw standards shouldn
’t be left open. Close the lid
immediately when not in use with the Aw measuring unit. Store and use at
room temperature and away from sunlight (at +15°C to +25°C).
