AquaLab 17 APPENDIX C
17 Appendix C
AquaLab Verification Standards
Application Note
Using AquaLab is easier then ever. Pre-packaged standard salt solu-
tions are immediately available for performance verification, saving
you time and money. Validation and documentation for GMP and
GLP has also become easier. Operate your instrument with cer-
tainty and insure the quality of your food product by using low cost
precision salt solutions.
• No need to purchase and store reagent grade salts.
• No additional laboratory equipment necessary.
• Avoid solution handling and mixing errors.
• Save technician time.
The AquaLab should be verified against a known salt standard daily.
For high use or batch processing, the instrument should be checked
regularly against a known salt standard of similar water activity.
Checking the water activity of a standard solution alerts the oper-
ator to the possibility of contamination of the unit or shifts in the
linear offset from other causes.
Now, you can verify AquaLab performance with confidence. Per-
formance Verification Standards in five water activity levels; 0.984,
0.920, 0.760, 0.500, and 0.250 a
w
. Order your calibration salt stan-
dard of similar water activity today.
Uncertainties Using Saturated Salt Solutions
The water activity values listed in our operator’s manual for sat-
urated salts were reprinted from Greenspan (1977). His method for
determining water activity was to combine all of the available data
from tests by other researchers. He did not set up any experiments of
his own. The uncertainty he published is due to variation among the
results from the different methods. There are, therefore, limitations
to the accuracy of these values. The instrumentation available for
109
To Next Page
Loading...
Need help?
General
