Thermo Fisher Scientific Alpha pH 550 - Manual (Page 20)

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4 C A L I B R AT I O N M O D E
4.1 Preparing the Monitor & Electrode for Calibration
Before starting calibration, make sure that the pH Monitor is in appropriate
measurement mode (pH or ORP). When the monitor is switched on, it starts up with
the measurement mode last used. For example, if the pH Monitor is switched off in
ORP measurement mode, it starts up in ORP mode when it is switched on. (Refer
Section 5.5 for switching measurement modes)
Be sure to remove the protective electrode storage bottle or rubber cap of the
electrode before calibration or measurement. If the electrode has been stored dry,
wet the electrode in tap water for 10 minutes before calibrating or taking readings to
saturate the pH electrode surface and minimize drift.
Rinse the electrode in de-ionized water after use, and store in electrode storage
solution. If storage solution is not available, use pH 4.01 or 7.00 buffer solution.
Do not reuse buffer solutions after calibration. Contaminants in the solution can
affect the calibration, and the accuracy of the measurements.
The pH Monitor features two internationally recognized pH buffer standards. Select
the buffer standard you require in the setup mode. (Refer Section 5.4) Available
buffer options are:
•
USA buffers --- pH 4.01, 1.68, 7.00, 10.01 and 12.45
•
NIST buffers --- pH 4.01, 1.68, 6.86, 9.18 and 12.45
4.2 Entering pH/ORP Calibration Mode
While in measurement mode, press the CAL key to access calibration mode. LCD
indicates ‘CAL PH’ (when measurement mode is pH) or ‘CAL OrP’ (when
measurement mode is ORP).
pH Calibration
OPR Calibration
Temp. Calibration
Calibration Mode
- See Section 4.3
- See Section 4.4
- See Section 4.5
CAL
HOLD
CAL
MEAS
pH
°C
ATC
READY
& To quit Calibration Mode
ENT