Start calibration, Calibrate known addition – Hach-Lange POLYMETRON 9240 Basic User Manual User Manual
Page 19
• LOW CAL SOL must be ≥ sample concentration of Na
+
and a minimum of 100 ppb
• HIGH CAL SOL = (LOW CAL SOL x 10)
Example 1: sample concentration of Na
+
= 20 ppb
→ LOW CAL SOL = minimum value = 100 ppb Na
+
→ HIGH CAL SOL = (100 ppb x 10) = 1000 ppb Na
+
Example 2: sample concentration of Na
+
= 450 ppb
→ LOW CAL SOL = ≥ sample concentration of Na
+
= 500 ppb Na
+
→ HIGH CAL SOL = (500 ppb x 10) = 5000 ppb Na
+
Note: The values LOW CAL SOL and HIGH CAL SOL must be entered into the system (see
on page 20 or
on page 20).
Automatic calibration
For an automatic calibration, the calibration solution must be between 10 ppm and 2000 ppm and
must respect the following rules:
• CAL SOL minimum = 10 ppm
• CAL SOL = (sample concentration of Na
+
x 1000)
Example 1: sample concentration of Na
+
= 0.1 ppb
→ CAL SOL = minimum value = 10 ppm Na
+
Example 2: sample concentration of Na
+
= 1 ppm
→ CAL SOL = (1 ppm x 1000) = 1000 ppm Na
+
Note: The value CAL SOL must be entered into the system (see
on page 20)
Start calibration
Select the START CALIBRATION option to calibrate the analyzer manually.
Calibrate known addition
1. Select the CAL.KNOWN ADDITION option to calibrate the analyzer by mixing the sample with a
known concentration of calibration solution. The concentration of the calibration solution is
defined in
on page 20.
2. The instrument first checks that the volume of calibration solution remaining is enough. If not, a
warning alarm is activated and the instrument returns to normal measurement with the original
parameters.
3. If the volume of solution is OK, the background point measurement (P0) to be used as the base
measurement value is taken. This is the measurement against the sample before any additions of
the calibration solution have been made.
4. The measurement must be stable and less than 1 per thousand of the calibration solution
concentration, otherwise the instrument returns to normal measurement with the original
parameters. Provided the measurement is OK, the P0 measurement details are displayed on
screen.
5. If the reactivation frequency parameter is not zero (as is highly recommended), the electrode will
be reactivated.
6. When the reactivation process is complete, the overflow vessel is rinsed to remove all traces of
sample.
7. After rinsing, the overflow vessel is re-filled with sample plus 2mL of the calibration solution.
8. The sample is then measured and the details displayed against P1.
9. When the measurement is stable, the details are displayed at the top of the screen against
measurement P1.
10. The overflow vessel is then rinsed and re-filled with sample plus 20mL of the calibration solution.
11. This sample is then measured and the details displayed against P2.
12. Once the final measurement is stable, the offset and slope for this calibration are calculated.
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