Thermo Scientific Orion 320, User Manual

Page: 42 / 67

5-10 Thermo Scientific Orion 320, 350 and 370 PerpHecT
®
LogR
®
Meter User Guide
A calibration should be performed before concentration is measured . A
two point standard calibration should be performed at the beginning of
each day and every time electrodes are changed to determine the slope of
the electrode . This serves the dual purpose of determining if the electrode
is working properly and storing the slope value in memory . Refer to the
electrode user guide for the recommended calibration frequency .
During calibration, always use the most dilute standard first . The meter
will automatically recognize the slope (i .e ., will recognize anion or cation
electrodes) . Standards should bracket the sample range and be in the same
concentration units . The electrode slope displayed after the calibration is
the slope between the two points used for the calibration curve .
Any convenient concentration units can be used, including molarity
(M), ppm, percent (%), etc . The meter will not display the units, so the
operator must keep the type of concentration units consistent between
calibration standards .
For the best results, allow all samples and standards to reach the same
temperature before measurement . An ATC probe may be used to read
temperature of samples and standards, but the meter does not compensate
concentration (ISE) measurements for temperature .
Note:
The LogR function must be disabled when using the ISE mode .
Note:
The 370 meter can only perform a two point ISE calibration .
ISE (Concentration)
Calibration