Hanna Instruments Edge - pH Calibration Procedure

Operational Guide
30
pH
Calibration
pH operation in standard mode oers full function of edge™ meter. This
includes seven standard buers and two custom ones. Five pH buers may
be used for calibration.
The instrument should be recalibrated whenever:
• High accuracy and sensor verication are required.
• The pH electrode is replaced.
• At least once a week.
• After testing aggressive chemicals.
• If ”CAL DUE” is displayed on the 3rd LCD line.
Every time you calibrate the instrument use fresh buers and perform an
electrode maintenance as required. It is advised to choose calibration buers
that bracket the sample pH.
Preparation
Pour small quantities of the buer solutions into clean beakers. If possible,
use plastic to minimize any EMC interferences.
For accurate calibration and to minimize cross-contamination, use two
beakers for each buer solution. One for rinsing the electrode and one for
calibration. If you are measuring in the acidic range, use pH 7.01 or 6.86 as the
rst buer and pH 4.01 (or 3.00*) as the second buer. If you are measuring
in the alkaline range, use pH 7.01 or 6.86 as rst buer and pH 10.01 or 9.18
as the second buer.
Procedure
Calibration can be performed using up to ve calibration buers. For accurate
measurements, a minimum of a three-point calibration is recommended. The
calibration buer can be selected from the calibration buer list that includes
the custom buers and the standard buers:
pH 1.68, 4.01 (pH 3.00*), 6.86, 7.01, 9.18, 10.01 and 12.45.
* pH 3.00 is only visible when using specic pH electrodes and will replace
4.01 pH buer.