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HND-R106
page 14
HND-R106 K09/0422
Standard cleaning:
apply 0.1 molar HCl-solution for at least 5 minutes or protein
cleaning agent.
The average service life of an electrode is 8 to 10 months but may be increased
to 2 years if electrode is well maintained and treated carefully. We regret not
being able to give more detailed information as this is highly dependent on the
individual case of application.
9.5 Calibration of pH measurement
The electrode data of pH electrodes are subject to fluctuation due to ageing and
manufacturing tolerances. Therefore, it is necessary to check the calibration with
buffer solutions before measurements take place. If deviations are too large, a
recalibration is necessary. See also chapter 18 Preparation of ph Buffer Solution.
Buffer solutions are liquids with an accurate pH-value. The following buffers can
be used for calibration:
- Technical buffer series PHL (ready to use, pH 4.01, pH 7.00 und pH 10.01)
- Standard series GPH (buffer capsules to be mixed with water pH 4.01, pH 7.00
and pH 10.01) - DIN series CAL dIn (pH 1.68 (A), pH 4.01 (C), pH 6.87 (D), pH
9.18(F) und pH 12.45(G))
- Arbitrary buffer CAL Edit (neutral buffer ranging from 6.5 ... 7.5pH)
Service life of a buffer solution is limited and will be further reduced unless
the electrodes are properly rinsed and dried when changing over the
solutions. This may even result in incorrect calibration! We recommend to
use new buffer solution for calibration, as far as possible, and to rinse with
deionized or distilled water.
9.5.1
Automatic temperature compensation during calibration
Both the signal of the pH-electrode and the pH-buffer are depending on
temperature. If a temperature probe is connected, the temperature influence of
the electrode is compensated automatically during measuring as well as during
calibration. Otherwise enter actual buffer temperature as accurate as possible
(see below). When working with the standard or DIN-buffer series, the influences
of buffer temperature are also compensated. If buffers are entered manually,
make sure to enter the pH-values of the buffers at the relevant temperature to
ensure optimum calibration of the device.