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4
pH Measurement
4.1
Information regarding pH Calibration
4.1.1
Things needed in addition to what’s included in the kit
A clean cup, distilled water (8-16oz), and tissue papers for rinsing and drying the probe.
4.1.2 Electrode Connectors
The pH electrode has two connectors: the BNC connector connects the pH probe; the RCA connector
connects the temperature sensor. Plug these two connectors into ‘pH/mV” and “TEMP” sockets. Please
note not to pull the cables in case of poor contact. Please keep the connectors clean and dry. Refer to
section 1.3 regarding how to properly maintain the pH electrode.
4.1.3 Use the Electrode
Screw off the probe cap, and put it aside (do not dump or spill the 3M KCL solution). Prepare a cup of
distilled (or deionized) water, and rinse the electrode in it for a few seconds. Gently shake the probe to
remove excess water, and dry it with clean tissue paper (DO NOT rub or wipe the probe, just use paper
to dap off excess water). Unplug the blue rubber plug; insert the probe into the test sample, gently stir the
probe for a few seconds; wait for the stable reading (a smiley face appears and stays) and then record
the reading. When test is finished, plug on the blue rubber plug and rinse the probe with distilled water;
then place the electrode in the probe cap with 3M KCL solution and tighten the cap so as to keep the
sensitivity of the pH sensor.
NOTE: All the tests should be sample tests, meaning after measurement, the samples should be
abandoned and not be used for its original purpose again.
4.1.4 Standard Buffer Solution
The meter adopts 3 series of standard buffer solutions: USA, CH, and NIST. They can be selected in
parameter P1.1 (see Section 6.3) as showed in Table-2 (default standard series is USA)
Table-2
Calibration icon
pH standard buffer series
USA
CH
NIST
3-Point
calibration
1.68 or 4.00 pH
1.68 or 4.00 pH
1.68 or 4.01 pH
7.00 pH
6.86 pH
6.86 pH
10.01 pH
9.18 pH
9.18 pH
