YSI 6000UPG - Manual (Page 39)

3-7
AMMONIUM (NH
4
+ ) and NITRATE (NO
3
- ) 3-POINT
NOTE: The calibration procedures for ammonium and nitrate are similar to pH except for the
reagents in the calibration solutions. Suggested values for calibrants are 1 and 100 mg/L of either
ammonium-nitrogen (NH
4
-N) or nitrate-nitrogen (NO
3
-N).
NOTE: The following procedure requires one 500 mL portion of 100 mg/L calibrant and two 500
mL portions of 1 mg/L calibrant. The 100 mg/l solution and one of the 1 mg/L solutions should be
at ambient temperature. The other 1 mg/L solution should be chilled to less than 10 C
°
prior to
beginning the procedure.
CAUTION: Proper calibration of the ammonium and nitrate sensors requires that the pH,
conductivity, and temperature probes also be immersed in the same solution as the sensor being
calibrated. Therefore, do not remove the probe guard and attempt to immerse individual sensors in
different vessels. For the ammonium and nitrate sensors to function at all, there must be solution
contact between the pH and the ammonium or nitrate probe.
Place 500 mL of 100 mg/L standard into a clean calibration cup. Carefully immerse the probe end
of the sonde into the solution.
Allow at least 1 minute for temperature equilibration before proceeding.
Select 7. Ammonium or 8. Nitrate to access the appropriate calibration choices. Then select
3. 3-Point. Press Enter and input the concentration value of the standard as requested or accept
the default. Press Enter and the current values of all enabled sensors will appear on the screen and
will change with time as they stabilize in the solution. Observe the readings under NH4+ or NO3- .
When they show no significant change for approximately 30 seconds, press Enter.
After the second value calibration is complete, as instructed, Hit any key to continue.
Rinse the sonde in water and dry the sonde prior to the next step.
Place 500 mL of the ambient temperature 1 mg/L standard solution in a clean calibration cup.
Carefully immerse the probe end of the sonde into the solution.
Allow at least 1 minute for temperature equilibration before proceeding.
Press Enter and input the concentration value of the standard as requested or accept the default.
Press Enter and the current values of all enabled sensors will appear on the screen and will change
with time as they stabilize in the solution. Observe the readings under NH4+ or NO3- and when
they have show no significant change for approximately 30 seconds, press Enter.
After the second value calibration is complete, as instructed, Hit any key to continue.
WARNING: AMMONIUM AND NITRATE SENSORS CAN ONLY BE USED AT DEPTHS
OF LESS THAN 50 FEET (15 METERS). USE OF THE SENSORS AT GREATER DEPTHS IS
LIKELY TO PERMANENTLY DAMAGE THE SENSOR MEMBRANE.