Nova-Tech 2700 Series Benchtop Meters - Manual (Page 16)

12
5. pH Calibration (with preset buffer group)
For best results, periodic calibration with known accurate standards is
recommended prior to measurement. Calibrate with standards that bracket your
intended measuring range while including a neutral point (7.00, 6.86, or 6.79). For
example, if you expect to measure samples from pH 6.2 to 9.5, calibration with
4.01, 7.00, and 10.01 will work well.
The 2700 series meters can be calibrated with up to 5 preset or custom buffers
(up to 6 with DIN buffer group). The non-volatile memory retains all calibration
values upon meter shut down.
The 2700 series automatically recognizes the following pH calibration buffers in
the groups listed below. See
Section4—Buffer to select a different buffer group;
Buffer Group pH Values
USA 1.68, 4.01, 7.00*, 10.01, 12.45
NIST 1.68, 4.01, 6.86*, 9.18, 12.45
DIN 1.09, 3.06, 4.65, 6.79*, 9.23, 12.75
USER 1 1.68, 4.01, 7.00*, 9.18, 12.45
USER 2 1.68, 4.01, 6.86*, 10.01, 12.45
CUSTOM Any 2 - 5 values, ≥ 1.0 pH unit apart
*Required as 1
st
calibration point value (offset determination)
To eliminate temperature errors associated with the pH electrode, attach the
automatic temperature compensation (ATC) probe for best accuracy. Without
temperature compensation, pH accuracy will worsen as samples deviate from
25ºC and pH 7.
If the pH electrode has been stored dry, soak in storage solution for 10 minutes
before calibrating or taking readings to saturate the pH electrode surface and
minimize drift. If storage solution is not available, use a neutral pH buffer. Do not
reuse buffer solutions after calibration. Contaminants in the solution can affect the
calibration, and eventually the accuracy of the measurements.
1) Turn meter on, press MODE if needed for pH Measurement.
2) Rinse the pH and ATC electrodes with clean water then submerse in neutral
pH buffer—the 1st calibration point must be either 7.00, 6.86, or 6.79
depending on the buffer group used.
3) Press CAL to enter calibration mode.