Thermo Scientific Orion 320, User Manual

Page: 43 / 67

5-11 Thermo Scientific Orion 320, 350 and 370 PerpHecT
®
LogR
®
Meter User Guide
1 . Attach the ion selective electrode (ISE), and half-cell reference electrode
(if a half-cell ISE electrode will be used), to the meter .
2 . In the measurement mode, press the mode key until the conc icon is
displayed .
3 . Select two standards that bracket the expected sample range . A decade
change in concentration between standards is recommended . For
example, if the expected sample concentration is 25 ppm, select
10 ppm and 100 ppm standards for calibration . Refer to the ion
selective electrode (ISE) user guide for information on adding ionic
strength adjuster (ISA) to all samples and standards as required .
4 . Place the electrode(s) into the least concentrated standard .
5 . Press the cal key to initiate calibration sequence . The display will show
CAL for two seconds . Then P1 will be shown in the upper display
field . When the ready icon is shown, indicating electrode stability, use
the scroll (
▲ ▼
) keys to set the value of the first standard . Press the yes
key to accept the standard one value .
6 . Remove the electrode(s) from the first standard, rinse the electrode(s)
with distilled water and place the electrode(s) in the most concentrated
standard .
7 . P2 will be shown in the upper display field . When the ready icon is
shown, indicating electrode stability, use the scroll (
▲ ▼
) keys to set the
value of the second standard . Press the yes key to accept the standard
one value .
8 . The slope will be displayed in mV/decade . A printout will occur if an
external printer is connected to the meter . The meter will automatically
proceed to the measurement mode .
9 . Remove the electrode(s) from the second standard . Rinse the
electrode(s) with distilled water and place the electrode(s) into a sample .
10 . Record the concentration and temperature directly from the meter
when the ready icon is displayed or when the electrode signal is stable .
Two Point ISE Calibration