NEULOG AMMONIUM LOGGER SENSOR GUIDE
NeuLog ammonium logger sensor
NUL-240
The NeuLog ammonium ion sensor can be used for any science experiment which
utilizes ammonium concentration readings such as in the fields of Environmental
Science, Ecology, Chemistry, Biology, etc.
Among hundreds of possible experimental subjects that can be studied with the NUL-
240 sensor are: chemical reactions, water quality, environmental health, small animal
behavior, ecological studies, and many more.
The ammonium sensor’s measurement units are:
Milligrams per liter (mg/L): SI measurement unit for density of a solid
dissolved in a liquid.
Parts per million (ppm): The total amount of a specific molecule (ammonium
for example) per million molecules in a sample.
Ammonium sensor usage:
The ammonium sensor’s electrode uses a PermaFil (non-refillable), ion-selective
electrode. The reference chamber is gel filled and sealed; therefore, no reference
filling solution is required.
Usage guide:
Concentration range
1M to 5x10
-6
M
0.01 to 18,000 ppm
pH range
4 to 10 pH
Temperature range
0 to 50°C
Minimum sample size
3mL in a 50 mL beaker
Reproducibility
±4%
Electrode resistance
1 to 4 megaohms
Equipment required:
Wash bottle with distilled or deionized water
Several clean beakers
1 mL, 10 mL and 50 mL pipettes (a 50 ml graduated cylinder can also be used).
Technical notes:
All standard solutions should be prepared fresh.
The standard solutions should be at the same temperature as the sample.
Use ISA in all solutions.
Note:
ISA is added to all solutions to ensure the samples and standard solutions
have the same ionic strength; the ratio is 1:50
Electrode preparation:
1.
Remove the protective cap encasing the ammonium probe’s electrode.
CAUTION: Do not touch the PVC membrane at the end of the probe with
your fingers.
2.
Rinse the electrode with deionized water and blot dry. Be sure not to rub as this
will harm the sensor.
3.
Soak the electrode in deionized water for 10 minutes, then in a diluted
ammonium standard solution (either 0.0001 M or 1 ppm) for two hours until
ready for use.
4.
For preparing the 1 ppm standard solution, mix one drop of the 1000 ppm
standard solution with 20 drops of ISA and add deionized water up to a total of
40 ml solution (assuming one drop equals 0.04 ml). It is also possible to use a
micropipette if available.
Offsetting the sensor:
Be sure to offset the ammonium sensor once daily during periods of regular usage.
1.
Prepare the electrode as described in the “Electrode preparation” guide above. If
you have already prepared the electrode in the last three days and stored it as
described in the "Electrode storage" section then you do not have to repeat it
before offsetting the sensor.
2.
Prepare the offsetting solution: Mix 1 ml of the ISA solution with 0.5 ml of the
1000 ppm standard solution. Add deionized water up to a total of 50 ml. You will
get a 10 ppm solution.
3.
Rinse the electrode with deionized water, blot dry and place in the beaker.
4.
After a stable reading has been reached,
press the “Start/Stop” button located
on the sensor’s faceplate for 4 seconds.
5.
Rinse the electrode once more with deionized water and blot dry.
6.
The ammonium sensor is now ready for use.