Accumet XL 20 User Manual page 141

Ion Operation: Analate Addition Method
Measuring Concentration in Samples Using the Analate Addition Method
The analate addition method is useful when your sample is at an elevated temperature and you
want to negate the effect that temperature will have on the concentration calculation. This method
is also useful if you have only a small amount of sample available.
The analate addition method differs only slightly from the known addition method (see 'Ion
Operation: Known Addition Method' section). The difference is the solution that you are taking
your initial mV reading in is actually the standard and not the sample of interest. The difference in
mV readings of the standard before and after the sample is added is used to calculate the
concentration of the ion of interest. With the analate addition method, both the sample and the
standard solution contain the ionic species of interest. See ISE Theory on 'Appendix: ISE
Theory' section.
Taking an Analate Addition Measurement
1. Immerse the ion selective electrode in a known volume of the standard solution.
2. Stir the standard.
3. Wait for the reading to stabilize (STABLE will appear). Touch AA to take the first reading.
4. Add a known volume of sample solution to the standard solution
5. Wait for the reading to stabilize (STABLE will appear). Touch AA to take the second
reading.
6. Use the keypad to enter the sample volume.
7. Touch Enter to accept the value.
8. Use the keypad to enter the standard volume.
9. Touch Enter to accept the value.
10. Use the keypad to enter the volume of ionic strength adjuster used. If no ISA was used,
enter a value of zero.
11. Touch Enter to accept the value.
12. Use the keypad to enter the concentration of the standard solution.
13. Touch Enter to accept the value. Your Analate Addition result is now displayed.
14. Touch Print to send the data to a printer
OR
Touch OK to return to the Measure screen for a new measurement.
XL25, 50 and 60 meters
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