YSI ADV6600 - Manual (Page 68)

Section 4. Calibration and Diagnostics
ADV6600
Y S I
Environmental
Page 58
A 2-point calibration is performed using two calibration standards that are both at approximately the
temperature of your environmental sample. In this procedure, the Cl
- sensor is usually calibrated
using solutions that contain 1 and 100 mg/L of chloride (Cl - ).
A 3-point calibration assures maximum accuracy when the temperature of the media to be
monitored cannot be anticipated. This procedure utilizes three calibration solutions, two at ambient
temperature and one at a temperature significantly different from ambient. The recommended order
of calibration standards is:
1. 1000 mg/L chloride (Cl
-
) standard at ambient temperature
2. 10 mg/L chloride (Cl - ) standard at ambient temperature
3. 10 mg/L chloride (Cl - ) standard at a different temperature (usually lower) than
ambient. For best results, ensure a temperature difference of at least 10 C
° between
the second and third standards.
Calibration:
1. Attach the ADV6600 to a ring stand in an inverted position with the clean, dry calibration cup
attached.
2. Add enough chloride standard to the calibration cup to ensure that the chloride, pH, and
temperature sensors are completely covered. Allow at least 1 minute for temperature
equilibration before proceeding. (Allow at least five minutes for the third, chilled standard in a
3-point calibration.)
3. From the Calibrate menu, select ISE Cl
-
to access the chloride calibration choices and select
either a 1-point, 2-point, or 3-point calibration.
4. Input the value of the first standard at the prompt.
5. Press Enter and the current values of all enabled sensors will appear on the screen and change
with time as they stabilize in the solution. Observe the readings under Cl - and when they show
no significant change for approximately 30 seconds, press Enter. The display will indicate if
the calibration is accepted.
6. Press Enter again, as instructed on the screen. If a 2- or 3-point calibration was chosen, rinse
the sonde in water and dry the sonde before proceeding with the next nitrate standard, following
the same steps as outlined above.
Chloride sensors generally drift more than pH sensors. Be sure to check for this drift by placing the
probe in a standard at the end of each deployment.
The chloride sensor should not be exposed to pH calibration buffers. If accidentally exposed, the
chloride readings will be erratic and take longer to stabilize. To restore function of the chloride
sensor, soak the probe in 1000 mg/L standard for a few minutes to several hours (or overnight).
Perform a new calibration and pay careful attention that nitrate readings are stable.