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Macro 900 Operation Manual
16.5. PT 1542 Nitrate Electrode
Nitrate (NO3) can be measured by the MAP 2000/2100 using the optional PT
1542 Nitrate electrode within a pH range of 3 – 10.
The Nitrate ISE electrode will suffer interference from Chloride, Bromide,
Fluoride, Sulphate, Chlorate and Perchlorate ions, which are similar in nature.
16.5.1.
Nitrate Calibration Solution Preparation
When a Nitrate ISE electrode is first installed, it must be calibrated at three
points. In order to achieve this, three batches of Nitrate calibration solution
must be prepared.
The solutions required are two 200mL batches of Nitrate at a concentration of
10ppm and one 250mL batch of Nitrate at a concentration of 100ppm.
The three calibration solutions should be freshly prepared by serial dilution from
1000ppm calibration standard. The following Nitrate standard is recommended:
Be sure to handle chemicals with care and to read and comply with all
health and safety advice.
Preparing the 100ppm solution
250mL of 100ppm solution is required. To prepare this, mix 25mL of 1000ppm
calibration standard with 225mL of deionised water.
Dispense 200mL of the 100ppm solution into a calibration bottle and retain
50mL for preparation of the 10ppm solution.
Preparing the 10ppm solution
A total of 400mL of 10ppm solution is required. To prepare this, mix 40mL of
the 100ppm solution you have just prepared with 360mL of deionised water.
Dispense the 10ppm solution into two calibration bottles (200mL each).
Achieving the correct temperature
During three point calibration, the 100ppm solution and one batch of the
10ppm solution must be at exactly the same temperature. The second batch of
10ppm solution must be at least 10ºC cooler.
In order to achieve this, one batch of the 10ppm solution should be put into a
refrigerator and the other two solutions should be put into a water bath at
25ºC.
Once all three solutions are at a stable temperature, calibration can begin.
© 2013 Palintest Ltd.
Part number: SS-712-1610
Description: 500mL Nitrate 1000ppm ISE
Supplier: T E Laboratories Ltd, Ireland.
Contact: http://www.tellab.ie
www.palintest.com
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