47
A
dvanced
S
ensor
T
echnologies,
I
nc. U.S.A.
Website:
www.astisensor.com
IOTRON
TM
Trademark of ASTI
IOTRON
TM
pH / ORP / ISE / DO / Conductivity Measurement Products Lines
APPENDIX “D”
HiQDT-pH “ Best Practice Tips for Calibration with pH Buffers
TEMPERATURE OFFSET CALIBRATION SETUP FOR AUTOREAD:
It is best practice to wait until the temperature reading on the sensor is no longer moving before selecting the
setup temperature and starting calibration(s) with pH buffers. The temperature of the sensor may take some
time to reach the ambient conditions of the pH buffer solution(s) if it was previously installed into field service
at conditions that are significantly below or above the ambient temperature.
GENERAL BEST PRACTICE COMMENTS FOR CALIBRATION WITH pH BUFFERS
Only the amount of buffer required for the given calibration should be dispensed. Buffers should not be
reused to avoid dilution & cross-contamination. Buffers should not be left exposed to air or direct light for
prolonged periods of time to avoid the impact of dissolved carbon dioxide from the atmosphere and other
potential decomposition pathways. Special care should be taken the pH buffers above 7.00 are always fresh
when used for calibrations as these tend to loose the integrity of their values much faster than pH buffers
below 7.00. Buffers should be stored in a cool, dry location away from light and chemicals. The pH sensor
should at a stable ambient temperature before performing any calibration.