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4.
For tough contaminants, soak the electrode in Apera cleaning solution (AI1166) for 30 minutes.
Then use a soft brush to remove the contaminants. Afterwards, soak the electrode in 3M KCL
solution (SKU: AI1107) for at least 1 hour. Rinse it off, then re-calibrate it before using again.
5.
The connector of the electrode should be kept clean and dry. If contaminated, please clean it
with medical cotton and isopropyl alcohol and blow-dry it to prevent short circuit of the
electrode or slow response of the electrode.
6.
The electrode should avoid testing strong acid and strong alkali solutions, as well as
dehydrating media such as absolute ethanol and concentrated sulfuric acid. If testing such
solutions, the immersion time should be minimized and the electrode should be carefully
cleaned after use.
7.
Every pH electrode will eventually age and fail. The typical service life of Apera pH electrodes
is 12 to 24 months depending on the frequency of usage and how well you keep it clean and
properly stored. We recommend replacing your electrode every 12-18 months to ensure the
best performance.
5.2
pH calibration related information
5.2.1 Standard buffer solution
The instrument adopts three series standard buffer solution, USA, NIST and CH series, and also
customized solution. Please see Chart – 2 for the three series of standard buffer solution. The detail
of customized solution, see clause 5.4.
Chart -2 pH standard buffer solution series
Calibration indication icons
pH standard buffer solution series
USA series
NIST series
CH series
Three-point
calibration
or
pH 4.00 or 1.68
pH 4.01 or 1.68
pH 4.00 or 1.68
pH 7.00
pH 6.86
pH 6.86
or
pH 10.01 or 12.45
pH 9.18 or 12.46
pH 9.18 or 12.46
Note: calibration indication icons are example of USA series.
5.2.2 Three-point calibration
The instrument can perform 1~3 point calibration. In three-point calibration mode, the first point
calibration must use 7.00 pH (or 6.86 pH) standard solution, then select other standard solution to
perform the second and the third point calibration. See chart – 3. Users can choose two-point
calibration of pH 7.00 and pH 1.68 for strong acidic solutions (<pH 2), or pH 7.00 and pH 12.45 for
strong alkaline solutions (>pH 12).
