METER AQUALAB User Manual

40
VERIFICATION AND CALIBRATION
Table5 Temperature correction of verification standards
Temperature
(°C)
Water
0.50 mol/kg
KCL
2.33 mol/kg
NaCl
6.00 mol/kg
NaCl
8.57 mol/kg
LiCl
13.41 mol/kg
LiCl
17.18 mol/kg
LiCl
15 1.000 0.984 0.923 0.761 0.492 0.238 0.140
20 1.000 0.984 0.922 0.760 0.496 0.245 0.145
25 1.000 0.984 0.920 0.760 0.500 0.250 0.150
30 1.000 0.984 0.920 0.760 0.504 0.255 0.155
35 1.000 0.984 0.920 0.760 0.508 0.261 0.160
40 1.000 0.984 0.921 0.760 0.512 0.266 0.165
50 1.000 0.984 0.894 0.740 0.517 0.275 0.172
NOTE: The AQUALAB VSA measures these verification standards to ±0.005 a
w
, ±0.02 with volatiles on yes. The readings
may lead to one of three outcomes.
a. If the AQUALAB VSA reads within ±0.005 a
w
of the first verification standard, take
two readings of the 0.76 a
w
standard. The second water activity reading for the
second verification standard should be within ±0.005 a
w
.
b. If either verification standard is not correct, it is probably due to contamination
of the sensor chamber. Clean and air out the chamber (Section5) and repeat
verification from step2.
c. If readings are consistently outside the water activity of the first verification
standard by more than ±0.005 a
w
, a linear offset can be applied. Adjust the reading
to match the correct verification standard value (Section6.2).
Measure verification standard
Clean sample
chamber
Reread first
standard
Go to offset
procedure
Go to sampling
procedure
Read second
standard
Clean sample
chamber
Repeat process
Figure 29 Verification standard flowchart. A check indicates AQUALAB VSA verified the standard
within specification; a cross indicates AQUALAB VSA did not verify the standard within specifications.

METER AQUALAB Specifications

General

Brand	METER
Model	AQUALAB
Category	Measuring Instruments
Language	English